Article

Natural and synthetic rubber/waste – EVA (Ethylene-Vinyl Acetate) composites for sustainable application in the footwear industry

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  • University of Porto - FEUP - LEPABE
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Abstract

The production of natural and synthetic rubber/waste – EVA (Ethylene-Vinyl Acetate) composites was performed using natural rubber, styrene-butadiene rubber or acrylonitrile-butadiene rubber and 10–20 parts per hundred rubber (phr) of waste. Several physical and mechanical properties of the composites were further determined according to the requirements of the footwear sector. Rheometry and ageing tests were also performed. The effects observed on the crosslinking formation during vulcanization of each composite were negligible. The flexion, density, hardness and abrasion of all composites, produced at a laboratory (10–20 phr) and industrial scale (20 phr), were not significantly affected by the addition of waste. The tear strength and the tensile strength were the most affected properties, namely for the Natural Rubber/Waste – EVA composites, where EVA acted as filler (tear strength > 13 N mm−1, breaking load > 15 MPa). The study confirms the possibility of a sustainable application of EVA – waste in the footwear industry through the production of eco-composites.

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... In Brazil, Moreira and Soares (2002) obtained excellent mechanical properties, with more uniform morphology (using dynamic mechanical and tensile analysis), in an acrylonitrile-butadiene rubber (NBR) matrix blend at 50 phr, using crushed EVA waste (100-350 mm). In Portugal, Lopes et al. (2015) studied composites containing both natural and synthetic rubber, and varying concentrations of EVA residue, using both laboratory (10-20 phr) and industrially (20 phr) processes. With the addition of EVA waste for reinforcement, the density, hardness, flexion, and abrasion remained mostly unaffected, yet tensile and tear strengths were improved. ...
... Certainly, for EVA microcellular foams with butadiene rubber blends (Maiti et al., 2012) the high CaCO 3 content had a crucial effect. The natural and synthetic rubber -EVA waste composites reported by Lopes et al. (2015) (in shoes) also presented lower tear strengths than EVA-B/EVA-w composites. Foam composites containing EVA waste are often quite different, for example in the present work, peroxide was used as a crosslinking agent, while Lopes et al. (2015) used sulfur, although the concentrations used were similar in both studies. ...
... The natural and synthetic rubber -EVA waste composites reported by Lopes et al. (2015) (in shoes) also presented lower tear strengths than EVA-B/EVA-w composites. Foam composites containing EVA waste are often quite different, for example in the present work, peroxide was used as a crosslinking agent, while Lopes et al. (2015) used sulfur, although the concentrations used were similar in both studies. The compression set (CS) reveals the reduction in sample thickness after being subjected to compression. ...
Article
Ethylene vinyl acetate copolymer blends (EVA-B), with vinyl acetate set at 19 % and 28 % by weight (wt%), were mixed with EVA waste (EVA-w), (a reticulated and micronized ethylene vinyl acetate copolymer) from injection branches and defective midsoles. The EVA-B/EVA-w composites were prepared with 15, 25, and 35 per hundred rubber (phr) EVA-w using a Banbury mixer to mix all components. Afterwards, the mixture was submitted to compression molding to obtain expanded EVA-B/EVA-w composite plates. A standard compound, provided by a Brazilian footwear industry (EVA-ref), was used as reference for thermal and mechanical property comparisons. During the thermal analysis, when increasing the EVA-w content, a delay in the deacetylation of the EVA-B composites in relation to the EVA-ref was observed. There was also an increase in the maximum degradation rate temperature and a reduction in loss of mass in the first decomposition event. In the second event, the maximum temperature did not vary in the composites with EVA-w added as compared to the EVA-ref. The residue content increased at 600 • C, indicating that EVA-w acts as a filler for EVA-B. The mechanical properties evaluated were hardness, tension at break, elongation at break, tear strength, compression set, and shrinkage. Addition of EVA-w to the composites (comparing 15 phr-35 phr) increased tear strength properties by 4 %, (EVA-w acts as a nucleation cell agent, increasing the EVA foam cell density). However, shrinkage increased by roughly 35 % above the specifications for footwear applications. Hardness increased by 5 %, tensile strength increased by 10 %, and elongation at break decreased by roughly 4 %. The compression set property increased by nearly 5 % with the EVA-w content (due to decreasing matrix elongation). Thus, EVA-w acts as a reinforcement filler for EVA-B. A statistical study based on composite performance indices for the mechanical properties, and a cost analysis was performed. Except for the average linear shrinkage (35 phr EVA-w composite), all other studied composites met the mechanical property specifications for sports shoe midsoles. The best combination for process performance and cost analysis was for the EVA-w composite at 25 phr.
... This can be caused by rubber recycle properties, which is denser and harder so that the more recycle added to the rubber vulcanizate will increase the hardness. Besides, the hardness value and mechanical properties will increase with the increase in crosslink density, which is linearly affected by the number of cross bonds between the polyisoprene aldehyde group and the condensed aldehyde group in non-rubber which is formed from the addition of filler material [9,11,12]. ...
... This can be caused during the vulcanization process that affects the density of g/cm 3 that binds the molecule to the rubber so that the rubber vulcanizate becomes denser and makes its specific gravity more significant. Besides, rubber vulcanizates which contain both reinforcing and non-reinforcing fillers with a higher quantity will be directly proportional to the contribution of the weight of the rubber compound and are also linear with an increase in specific gravity [11,13]. ...
... The less the amount is eroded indicates the better the rubber volcanic. The volcanic erosion resistance related to the value of specific gravity where the specific gravity can describe the number and density of chemical compounds per cubic mm is directly proportional [11]. The abrasion test is a mechanical test to determine the abrasion level (eroded) of a test specimen by rubbing that specimen without using grade 60 sandpaper. ...
Conference Paper
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One of the various rubber product problems is rubber recycle disposal management due to rubber material is not decomposed easily so that recycle disposal leads to an environmental pollution. In this context, recycle recycling research is carried out by mechanical degradation. Reusing recycle in formulation as a filling material and varied by 0.0; 7.5; 15.0; 22.5; 30.0; 37 phr of rubber weight. Compounds with a variety of rubber recycle products will be vulcanized. The vulcanization result will be tested for properties of functional group, microscopic structure and mechanical, involving hardness, specific gravity, abrasion resistance, tensile strength, elongation at break and tear strength of vulcanized rubber. Based on the results of tests that have been carried out, several findings as follows are: the mechanical properties obtained in formulas I, II, III and IV still meet these requirements while formulas V and VI values are under the quality requirements, the addition of various rubber recycle does not show changes in functional groups contained in vulcanization activity but peak intensity of the sample that has been combined with rubber recycle is higher, especially the peak at the wavelength of 1552 cm-1 associated with CO -C vibration, and variation of rubber recycle show that the smaller size of rubber recycle is more dispersed and visible.
... Campuran limbah phylon (100-350 mm) dalam matriks karet nitril (NBR) pada 50 phr memberikan produk dengan sifat mekanik yang sangat baik, dengan morfologi yang lebih seragam (menggunakan analisis mekanik dinamis dan tarik) (Moreira & Soares, 2002). Komposit yang mengandung karet alam dan karet sintetis, serta berbagai konsentrasi limbah phylon dapat meningkatkan kekuatan tarik dan sobek, namun tidak mempengaruhi kekerasan dan ketahanan abrasi (Lopes et al., 2015). Penambahan limbah phylon (15 hingga 35 bsk) pada alas kaki expanded EVA meningkatkan kekerasan 5%, kekuatan tarik 10%, dan kekuatan sobek 4% (Paiva Junior et al., 2021). ...
... Penelitian lain menyatakan bahwa terjadi peningkatan kekerasan karet nitril (NBR) dengan penambahan limbah phylon (Moreira & Soares, 2002). Penambahan limbah phylon juga meningkatkan kekerasan karet alam dan sintetis (Lopes et al., 2015). Komposit limbah phylon dan karet brown crepe pada outsole sandal outdoor menunjukkan nilai kekerasan yang lebih tinggi, menunjukkan bahwa partikel phylon yang lebih keras memiliki efek yang l e b i h b e s a r k e t i k a k o n s e n t r a s i n y a ditingkatkan. ...
Article
Full-text available
Pertumbuhan industri alas kaki meningkatkan jumlah limbah phylon. Limbah phylon yang tidak diolah dengan baik memberikan dampak buruk bagi lingkungan. Penelitian ini bertujuan untuk mendaur ulang limbah phylon sebagai bahan campuran utama untuk sol luar (outsole) sandal outdoor karena phylon umumnya digunakan pada outsole alas kaki aktivitas outdoor. Limbah phylon dicampur dengan bahan lainnya sesuai formulasi yang telah dirancang menggunakan kneader dan mesin two-roll mill, lalu dicetak menggunakan mesin hot press moulding pada suhu 140-150 oC selama 3 menit. Hasil penelitian menyatakan bahwa limbah phylon dapat didaur ulang menjadi bahan utama untuk pembuatan outsole sandal outdoor. Outsole yang dihasilkan pada berbagai formulasi memiliki permukaan rata dan tidak memiliki kecacatan seperti sobekan dan keretakan. Kompon yang menggunakan limbah phylon 13 phr memberikan kekerasan sebesar 65 Shore A dan indeks abrasi 29,12%, sedangkan kompon yang menggunakan limbah phylon 31 phr memberikan kekerasan sebesar 70 Shore A dan indeks abrasi 46%. Kekerasan dan indeks abrasi outsole mengalami peningkatan seiring bertambahnya bagian limbah phylon dalam kompon karet. Meskipun kekerasan outsole meningkat, namun outsole tersebut tetap tidak retak setelah dilakukan uji retak lentur.
... Lopes D et al. [5], compared the material strength of EVA plastic and rubber material. The rubber material has better strength and capability of the impact load stress absorption strength. ...
... The full material 600sector tyre is analysed using materials EVA plastic, rubber and reinforced rubber [5] [8]. The loads are applied [7] as shown in Fig. 3(a). ...
Article
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Mostly pneumatic tyres are used for fast moving vehicle and solid tyres are used in less load carrying slow moving vehicle. Conventional tyres are manufactured using materials like rubber, EVA plastic, etc. Based on the load carrying components of the frame body the number of tyres and the material of the tyre is decided for motion possibility and stability of the body. In this project we are going to analyze the non-pneumatic wheelchair tyre. The strength variation is analyzed by comparing existing tyre and non-pneumatic tyre pattern. And comparison is done for modification of existing design for improving properties like strength and durability.
... In the scientific literature, several studies were carried out to evaluate the feasibility of alternative recovery systems for EVA crosslinked waste. Lopes et al. [9] employed EVA waste as a filler for natural rubber, styrene-butadiene rubber, and acrylonitrile-butadiene rubber in compression molding processes. Two waste percentage contents were testes (10 phr and 20 phr) and footwear outsoles with good mechanical properties were produced. ...
... At a strain value of 9.5, the virgin EVA reaches a mean tensile strength value of 3.63 MPa, with a standard deviation of 0.12, while the recycled EVA exhibits a mean value of 3.33 MPa, with a standard deviation of 0.10. Such results demonstrate that, by dispersing the pre-vulcanized EVA in the virgin material, a reduction in the tensile strength equal to 8% is obtained, that is recycled EVA acts as a filler and tends to decrease the deformability of the virgin EVA, as reported also in [9]. ...
Article
Full-text available
Ethylene vinyl acetate (EVA) is a thermoplastic material largely used in the footwear industry. Indeed, it is employed to produce outsoles and midsoles with high shock absorption. For producing these parts of the shoes, EVA is injected into a heated mold. During this process, gates and runners, which are necessary to allow a correct infill of the mold, are generated and they are treated as scraps and disposed in landfill. In this paper, a method for recovering pre-vulcanized EVA waste is presented and the possibility of developing a recycled product is investigated. EVA waste was shredded and dispersed into virgin EVA with a weight content of 10%. This mixture was employed in an injection molding process to produce samples for characterizing tensile, compression, and abrasion resistances and compare them with those of virgin EVA. At the same time, the environmental sustainability of the recovery process was evaluated through the standard methodology of Life Cycle Assessment (LCA) by comparing the production of recovered outsoles with traditional virgin ones. The LCA was paired with a Life Cycle Costing analysis to quantify possible economic benefits of the innovative system. Even though the resistances are quite lower than the virgin EVA, the recycled one demonstrates remarkable benefits in terms of environmental and cost sustainability, paving the way for a zero-waste system to produce outsoles and, more in general, EVA components.
... The mechanical recycling of PU and EVA waste is highly challenging (recycling rate <5%) because of the permanent crosslinks formed in the molecular structure of waste EVA and PU, hampering the re-processing and re-melting (Correia et al., 2011;Lopes et al., 2015). As a result, mechanical recycling of such waste plastics produces lower-grade polymer products compared to the original materials (Pickering, 2006). ...
... To minimize the influence of crosslinks, the use of waste EVA and PU as fillers or modifiers was reported. For instance, waste EVA or PU could be incorporated into rubber to make soles or plates, improving their tensile strength and tear resistance (Lopes et al., 2015;Zia et al., 2007). Another way was to incorporate the waste EVA or PU into the cementitious composites to form lightweight concrete formulations characterized with only minor reduction of compressive strength and elastic modulus (Ben Fraj et al., 2010;Elgady and Supervisor, 2018). ...
Article
This work investigates the chemical recycling of shoe waste plastics, i.e. polyurethane (PU) and ethylene-vinyl acetate (EVA) using a pyrolysis-chemical vapor deposition process over Fe/MgO catalyst. Results suggested PU facilitated highly selective production of few-walled CNTs with small diameters and narrow size distribution while EVA tended to yield multi-walled CNTs. The synergistic interactions between pyrolysis gases components from PU and EVA allowed facile tailoring of CNT size distribution by using either sorted PU and EVA or mixture (EVA/PU) in appropriate ratios. CNTs derived from pure PU or EVA/PU were more suitable in designing effective electrocatalysts for CO2 reduction with Faradaic efficiency of 85–95% and CO current density of >9 mA cm⁻². This was because the presence of few-walled CNTs could enhance electrical conductivity and specific surface area without compromising the loading of active materials.
... The outsole is one of the important shoe components that directly contact with the ground. In the footwear industry, ethylene-vinyl acetate copolymer (EVA) is widely used in the manufacture of shoe components including outsoles and insoles (Lopes et al., 2015), which brings several benefits such as cost reduction, comfort, lightness, and softness (Ferreira, 2018). ...
... A study related to EVA as a material for shoe midsoles has been reported by Wang (2012) and Onodera (2017). Lopes et al. (2015) reported natural and synthetic rubber/waste-EVA (Ethylene-vinyl acetate) composites for sustainable application in the footwear industry. The production of many petroleum-based products, such as EVA, used to manufacture footwear results in serious environmental pollution when disposed of into landfills because of its less biodegradability. ...
Article
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The use of non-biodegradable material in shoe components has negative impacts on environmental sustainability when disposed into landflls due to poor biodegradability. This study prepared ethylene–vinyl acetate (EVA)/modifed starch expanded compounds as outsole material to overcome environmental pollution. This research aimed to investigate the effects of EVA/modifed starch ratio on the properties of the compound. Ethylene-vinyl acetate (EVA) copolymer was blended with a modifed cassava starch in various amounts (10-50 phr) using a two-roll mill. Effect of modifed starch content was characterized its tensile strength, elongation at break, tearing strength, 50% permanent set, density, abrasion resistance, flex resistance, biodegradability, and morphology. The optimum value of tensile strength (61.33 kg/cm²), elongation at break (895%), and tear strength (16.62 N/mm) were obtained for samples containing 20 phr modifed starch. The EVA compound containing 30 phr of starch showed the optimum 50% permanent set (4.85%) and the highest abrasion resistance with the smallest volume loss of 439.99 mm³. The addition of modifed starch up to 50 phr provided good flexural resistance to 150000 number of cycles. The morphology image showed that distribution of modifed starch particles was not homogeneously dispersed in the EVA/modifed starch expanded compound. Incorporation of modifed starch in EVA compound was improving its biodegradability.
... Polymeric materials, which are widely used in several industrial fields, are available at a low cost [1][2][3][4][5][6][7][8][9][10][11][12][13]. Among these compounds, natural polymers are very attractive. ...
... Grafting process is begun through production of free radicals along the polymeric backbone as well as monomer. Among the different techniques creating the radicals, redox initiation methods are widely utilized because (1) grafting can be done under milder conditions and (2) side reactions are at a minimum [18,19]. Potassium persulfate is a well-known redox initiator and has been successfully applied in grafting of vinyl monomers with alginate [20], starch [21], xanthan gum [22], bleached jute fiber [23] and hydroxypropyl methylcellulose [24]. ...
Article
Full-text available
In the present study, the preparation of a novel graft yield of acrylonitrile onto cross-linked (alginate/polyvinyl alcohol) (CAP) beads was considered in the presence of potassium persulfate (KPS) as an initiator. The effects of operational parameters such as time, temperature, amount of backbone, concentration of monomer and initiator on grafting percentage were evaluated. The grafting process was modeled using the Levenberg–Marquardt algorithm of artificial neural network. The high correlation (R² = 0.9913) between the experimental data and model outputs showed that the Levenberg–Marquardt network is able to predict the grafting of acrylonitrile on CAP backbone accurately. The physicochemical properties of grafted samples were investigated by Fourier transform infrared, scanning electron microscopy and thermogravimetric analysis (TGA). The decomposition temperature values obtained from TGA demonstrated that the thermal stability of CAP increased as a result of grafting. Finally, the results showed that grafting of acrylonitrile onto CAP beads successfully occurred under studied experimental conditions. Graphic abstract Open image in new window
... The last decade has seen a growing attention to sustainability in each commodity sector (Brunetti et al., 2013) and, in particular, in the footwear one (Lopes et al., 2015), where several interventions have been carried out in order to provide a concrete response to the need to adopt sustainable behaviors, such as minimization of chemical compounds typically used in the past, reduction of the noise produced by the machines operating in the plants, greater energy efficiency, improvement of the working conditions of the individuals involved in the design or production of footwear, and so on (Tartaglione and Corradini, 2013). ...
... In fact, some authors (Partridge 2014;Johnsen et al., 2014) emphasize the great attention paid to environmental issues by people, who seem to be more and more concerned about the dangerous effects of climate change (Schipper and Pelling, 2006), such as the melting glaciers caused by global warming, the depletion of natural resources, etc. Likewise, Lopes et al. (2015) even state that the adoption of sustainable practices can be understood as the driving force of the competition, the winning strategy to enable companies to reach and defend their success. ...
Article
Full-text available
Purpose of the paper: The work aims to achieve a twofold objective: highlight, through a big data analysis, the consumers’ perception about sustainability in the footwear context and provide useful considerations regarding the opportunities for companies to adequately manage the decision-making process in order to maximize the benefits and minimize the risks deriving from the definition and implementation of sustainability-oriented business strategies. Methodology: A text analytics study has been performed to understand the main variables that people consider when adopting their shoe purchasing behavior. In particular, the collection of the people’s opinions has taken place on Twitter, a well-known and widespread social network community. Findings: According to the big data analysis carried out, sustainability is ranked last among the factors capable of orienting the consumers’ purchasing choice, as demonstrated by the only 1311 posts on Twitter. Research limits: The automated collection of people’s posts has prevented from going deeper in understanding their real ideas about variables more capable of orienting their shoe purchasing behavior. Practical implications: The study suggests the importance to enhance managerial meta-capabilities for those footwear companies that are actively engaged in corporate sustainability. The systematic analysis of points of view, preferences and expectations would allow the development of innovative eco-value propositions in terms of both products (i.e. environmentally friendly shoes) and services (i.e. reverse logistics). Originality of the paper: The paper is based on an innovative technique of data analysis, carried out by means of a web crawler, software for automatically identifying, collecting and classifying a big number of terms, capable of facilitating the understanding of the investigated phenomenon.
... A combination of two monomers ethylene and vinyl acetate forms a copolymer known as ethylene vinyl acetate, which currently acts as an alternative for polyvinyl chloride since they have fewer harmful chemicals. Due to its strong resistance and flexibility, EVA is used in numerous industries, including the marine sector (fishing rods and reels), footwear industries, elastic packaging for goods, flexible hoses and more (Chang et al., 2014;Lopes et al., 2015). Freshwater fish, water samples, sediments, commercialised sea salts and even snow samples have all been shown to contain EVA (Arcadio et al., 2023;Li et al., 2021;Liong et al., 2021;Ohno & Iizuka, 2023;Parvin et al., 2021Parvin et al., , 2022. ...
Article
The growing amount of plastic waste in the environment is a result of the increased use of plastics in numerous areas of our daily lives. These plastics are broken down into microplastics (MPs), which are 5 mm or smaller in size. Sea cucumbers are consumed as an exotic delicacy worldwide, however, it is suspected that they could ingest the microplastics due to their nature as filter feeder. In this study, we have identified the MPs presence in the intestines of sea cucumber Holothuria scabra. A total of 30 sea cucumber H. scabra were collected during low tide at a muddy sandy area at Pulau Malawali using bare hands. The gastrointestinal tracts of H. scabra were removed and digested in NaOH. MPs were identified using light microscope and categorized into shapes and colours. Micro-Fourier Transform-Infrared Spectroscopy (µFTIR) analysis was carried out to identify the types of polymers. The majority colours of MPs were black (69.84%) and blue (18.65%). Fibres (98.38%) made up the majority of MPs followed by fragments (1.37%) and films (0.25%). Ethylene Vinyl Acetate (EVA), Melamine-Formaldehyde (MF) and Rayon were among the polymers identified. In conclusion, MPs were found in the intestines of the sea cucumber H. scabra and this could be from the ingestion of polluted sea bed. The importance of studying the presence of these MPs in sea cucumber allows us to assess the impact of plastic pollution on marine animals and ecosystems and understand the potential risks to both sea cucumber and human as consumers.
... Ethylene is a very important chemical raw material, which is widely used in the preparation of synthetic fibers [1], synthetic rubber [2], synthetic plastics [3], and other chemical raw materials. The ethylene production is one of the important level indicators of a country development [4]. ...
Article
Full-text available
Bimetallic catalysts have widespread applications in many reactions. Series of Ni/SiO2 catalysts containing different promoters were prepared by ammonia evaporation method in this work. The effect of Sn and Mg additives on the catalytic performance of nickel-based catalysts in acetylene hydrogenation was investigated. The introduction of Mg additives led to the over-hydrogenation of acetylene to ethane, vs. the Sn promoter increases the selectivity of the catalysts towards ethylene. The Ni7Sn/SiO2 showed the most superior catalytic performance. The effects of different additives on the active metals were investigated through a series of characterizations and thus the structure-performance relationship was well investigated. Graphical Abstract Reaction mechanism diagram of acetylene and hydrogen over Ni/SiO2 based catalysts.
... With an estimated annual production of 24 billion shoes [11] (most of which contain EVA soles), it is easy to understand the importance of reuse [12]. Lopes et al. [13] used EVA waste as a filler for natural rubber, styrene-butadiene rubber, and acrylonitrile-butadiene rubber in vulcanization/pressing sole manufacturing processes. Two percentages of waste were tested (10 phr and 20 phr) and the produced shoe soles showed good mechanical properties. ...
Article
This paper presents experiments on developing and characterizing biodegradable polymer composites based on polyvinyl chloride and expanded poly(ethylene vinyl acetate) (EVA) post-consumer waste. This type of waste is a thermoplastic material collected from the footwear industry, residues from the production of outer and intermediate soles and used footwear. It is used due to its shock absorption properties and low density (0.6-0.8 g/cm3). To make these products, EVA is injected into molds, a process that generates waste that cannot be reused. In this paper, a method of EVA waste recovery is presented and the possibility of developing a recycled product is investigated. Expanded EVA waste is cryogenically ground to sizes of min. 500 nm, functionalized by a mechanical process at temperature with polydimethylsiloxane (PDMS) and mixed in the composite in various proportions (10, 20, 50%). This composite will be made into a low-density product, with low cost, recovery and reuse of waste, and last but not least, biodegradable. The methodology for making the new materials involves the following steps: sorting waste, grinding, functionalization and compounding. These operations are easy to manage and do not involve new equipment. Compounding, the most important operation, will be performed on an extruder-granulator. The experimented biodegradable composites were physico-mechanically characterized. Waste transformation (ground and functionalized) into new value-added products will lead to remarkable improvements in the life cycle of raw materials and the sustainable use of this waste, contributing to sustainability, improving eco-efficiency and economic efficiency and reducing the “pressure” of waste on the environment.
... 둘째, 경제 적 지속가능성은 운송의 감소와 비용 낭비를 제거하는 것으로 원 자재비용을 낮춰 제품의 생산 비용 절감이 가능하다(Harrell and Mcconocha, 1992). 셋째, 이러한 환경적, 경제적 이득에 따라 기 업이 안정성을 획득함으로써 추가적인 기회를 도모할 수 있게 된 다. 일자리를 창출하거나 근로자 복지의 제고는 결국 사회적 지속 가능성에 영향을 미칠 수 있다(Lopes et al., 2015). 경제적 특성 은 소비자의 제품 또는 상표 선택에 있어 중요하게 여겨지는 요소 라고 할 수 있다(Kim, 2020). ...
Article
Sustainable fashion products have different characteristics from typical fashion products. Therefore, this study focuses on shoes while exploring the expansion and development of sustainable fashion consumption as well as consumers' perceptions of the sustainability approaches practiced by shoe companies. In-depth interviews were conducted with 24 consumers, who had purchased sustainable shoes, in order to understand their purchase decision-making process and consumption characteristics, using the seven stages of the EBM model. In the “need recognition” stage, the survey participants' social background and family influences were categorized as macro factors, while their personal background influences were categorized as micro factors. In the “evaluation of alternatives” stage, participants reconfirmed whether or not to make a purchase based on the product's properties, such as price, brand value, and offered services. In the “purchase” stage, participants' purchase channels were determined according to their preferences as well as the selection pattern they followed until the final purchase within the chosen channel. In the “consumption” stage, the start of product ownership coincides with the start of using the products after making a purchase. In the “post-purchase assessment” stage, higher positive experiences led to a higher repurchase intention of sustainable shoes, while negative experiences caused participants to defer consumption and made them experience a sense of guilt for failing to consume sustainably. During the “post-purchase behavior” stage, which focused on the categories that the customers prioritized, many participants spread information about sustainable fashion to specific individuals through active online WOM behavior.
... These polymers are used mainly for food packaging (Phuong et al., 2021) and electronic appliances (Ye et al., 2021), respectively. Other, less commonly-used, polymers were also found including: PEVA which is used to produce footwear (Lopes et al., 2015) and household products (Meng, 2014), Nylon 6 (used in fishing ropes and gear (Goswami et al., 2021)), and BCPP which is used in industrial applications (Li et al., 2002). ...
Article
The abundance and distribution of microplastics has largely increased during last years and the respective implications on the environment and human health is an emerging field in research. In addition, recent studies in the enclosed Mediterranean Sea in Spain and Italy have shown an extended occurrence of microplastics (MPs) in different sediments of environmental samples. This study is focused on the quantification and the characterization of MPs in the Thermaic Gulf in northern Greece. Briefly, samples from different environmental compartments such as seawater, local beaches and seven commercially available fish species collected and analyzed. MPs particles extracted and classified by size, shape, colour and polymer type. A total of 28,523 microplastic particles recorded in the surface water samples, with their numbers ranging from 189 to 7714 particles per sample. The mean concentration of MPs recorded on the surface water was 1.9 ± 2 items/m3 or 750,846 ± 838,029 items/km2. Beach sediment sample analysis revealed 14,790 microplastic particles, of which 1825 were large microplastics (LMPs, 1-5 mm) and 12,965 were small microplastics (SMPs, <1 mm). Furthermore, beach sediment samples showed a mean concentration of 733.6 ± 136.6 items/m2, with the concentration of LMPs being 90.5 ± 12.4 items/m2 and the concentration of SMPs being 643 ± 132 items/m2. Concerning fish deposition, microplastics were detected in intestines and mean concentrations per species ranged from 1.3 ± 0.6 to 15.0 ± 1.5 items/individual. The differences in microplastic concentrations between species were statistically significant (p < 0.05) and showed that mesopelagic fish contained the highest concentrations, followed by epipelagic species. The most common size fraction found in the data-set was 1.0-2.5 mm, and polyethylene and polypropylene were the most abundant polymer types recorded. This is the first detailed investigation of MPs in Thermaic Gulf, which raises concerns on their potential negative effects.
... The use of waste and non-valuable materials, for the manufacturing of composite materials, is another alternative. Composites with leather, natural rubber, and acrylonitrile-butadiene rubber particles, as reinforcements, are some examples of materials developed for applications that do not need high performance and environmental resistance [6,7]. Among the matrices, high-density polyethylene (HDPE), polystyrene (PS), and polypropylene (PP) are some examples, disclosed in the current literature [8,9]. ...
Article
The footwear processes generate a large amount of waste on the soles’ cutting and finishing steps. Styrene–butadiene rubber (SBR) is commonly used as feedstock for soles, mainly presenting good abrasion resistance, deformation and durability. These features make SBR a candidate for the manufacturing of non-slip surfaces, that provide softness, low density and wear resistance. The objective of this work was to develop a polymeric matrix composite material, using SBR scraps, from the shoes’ production, to design the non-slip surfboard decks. Composites, composed by different ratios of SBR (i.e., 20, 40, and 60 wt.%) and polymer matrices (i.e., polyvinylchloride (PVC), ethyl vinyl acetate (EVA), and styrene–butadiene styrene (SBS) rubber) were developed and characterized by tensile, morphological and apparent density. The main results showed that the SBS/SBR composite closely met the adhesion requirements for the final application, containing 20 wt.% SBR scraps.Graphical abstract
... The material has gloss and good clarity, hot-melt adhesive waterproof properties, resistance to UV radiation, stress-crack resistance, and low-temperature toughness. Hence, EVA copolymers have a broad range of applications early in hot melt adhesives [2] coatings [3] wire and cable applications [4], footwear industry [5], controlled release drug systems [6], packaging applications [7], wearable electronic devices for human health monitoring [8]. Despite the promising aspects of EVA for coating applications, it has some disadvantages such as low tensile strength and highly flammable and produces large amounts of toxic smoke during combustion. ...
Article
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Development of cotton fabric (CF) properties using nanocomposites via coating method was of considerable interest for wide applications. This article aims at developing CF properties by coating treatment using ethylene–vinyl-acetate (EVA), silicon dioxide (SiO2), aluminum oxide (Al2O3) nanoparticles and γ-irradiation widely used in waterproof and flame retardant applications. EVA-based nanocomposites, EVA/SiO2, EVA/Al2O3, and EVA/SiO2/Al2O3, were synthesized by γ-irradiation and the highest gel content of 81.2–95.3% was achieved at 30 kGy. The physicochemical properties of EVA-based nanocomposites were characterized by FT-IR, XRD, DSC and SEM techniques. Usage of irradiated EVA and EVA-based nanocomposites for treatment of CF by coating technique was successfully achieved. This technique provides a simple and versatile method leading to excellent uniform and smooth surface morphology without aggregation. The weight gain, mechanical properties, thermal properties, water vapor permeability and flame-retardant properties of the modified CF were evaluated. Moreover, compared with control CF, the resistivity of water absorptivity and hydrophobic property and the thermal stability were gained. The flame retardant properties of CF samples were performed using limited oxygen index (LOI) and vertical burning flame tests. LOI percentages of CF/EVA/SiO2, CF/EVA/Al2O3 and CF/EVA/SiO2/Al2O3 increased to 25.3, 27.5, and 29.3%, respectively. Untreated CF ignited and burned rapidly after 5 s. Meanwhile, the treated CF hold flame resistance properties and the burning time prolonged to 25 s. The results of the treated CF providing revealed hydrophobic and protective capability of the fabrics from being destroyed by burning, and support their further use in waterproof and flame retardant applications of fabrics.
... Additional experiments have shown that waste ground tire rubber can exert an excellent reinforcing influence on SBR solution, owing to the existence of the core-shell structured carbon black after being degraded by a heterogeneous process to less than 150 • C by soybean oil [35]. Rubber wastes also originate from the footwear industry sector, wherein 10-20 parts per hundred (phr) ethylene-vinyl acetate elastomer waste is mixed with natural rubber, styrene-butadiene rubber or acrylonitrile-butadiene rubber, then the composites are vulcanized; no significant effects were observed on the crosslinking formation of mixture [36]. ...
Article
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Economic, social, and urban developments generally require improvements in the transportation sector, which includes automobiles such as trucks, buses, trailers, airplanes, and even bicycles. All these vehicles use rubber tires. After consumption, these tires become waste, leading to enlarged landfill areas for used tires and implying additional harm to the environment. This review summarizes the growth of rubber recycling application and the sustainability of using waste rubber in the construction field. Furthermore, we provide methods to convert rubber waste to fuel or fuel additives by using tire-derived fuel and concentrate to pyrolysis, which are environmentally friendly and efficient ways. The related parameters such as temperature, pressure, and feedstock composition were studied. Most research papers observed that 500 °C is the optimal temperature at atmospheric pressure in the presence of a specific type of catalyst to improve pyrolysis rate, oil yield, and quality.
... When EVA scraps are recycled in polymeric matrices, conventional processes are adopted. In the footwear industry, the recycling potential of these compounds has been investigated via mechanical properties [13,14]. Knowledge of the rheological properties of rubber products is important to optimize its commercial production, however few works can be found addressing rubber waste added to footwear rubbers. ...
Article
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Ethylene vinyl acetate blends (EVA-B) (at 19 and 28 wt% vinyl acetate) were supplied by the footwear industry, along with an industrial (reference) compound labeled EVA-ref. EVA waste is an industrial sub-product crosslinked (injection sprues and unused midsoles), that was particulate through a micronization process and labeled as EVA-w. The objective of the present work was to evaluate processability and rheological parameters (using torque rheometry) when adding EVA-w to EVA-B. The EVA-w particle size distribution was bimodal, with an average diameter of 53.06 μm, and volume (%) D (10), D (50), and D (90) respectively equal to 12.47, 31.83, and 135.18 μm. However, this ample size distribution did not affect the composite mixing. FTIR-ATR analysis showed that no new crosslinking occurred after processing the composites. Low unit mixing energy (Wu), and mechanical work (as represented by ΔT values: torque stabilization temperature (Tstab)−test temperature (Ttest)) were required to mix the composites. Consequently, the dispersion of the EVA-w particles within the molten EVA-B occurred during the first 3 min of mixing, making it easier. The sensibility to shear-thinning behavior was more pronounced when adding EVA-w, especially at 25 phr. The m parameter was smaller in the composites as compared to the EVA-ref, and when adding EVA-w at 35 phr, it showed a tendency to increase. The average shear stress (τ\overline{\tau }) of the 15 phr composite was similar to that of the EVA-ref compound. Yet for 25 phr, a higher value was observed. The adding of EVA-w made the non-Newtonian behavior of EVA-B less pronounced. For all samples, the average viscosity (\overline{\upeta }) decreased with average shear rate (γ˙\overline{\dot{\gamma } }), revealing a pseudoplastic behavior.
... The main applications of EVA are in the food packaging sector, films for agriculture and in the formulation of adhesives [9]. In the footwear industry, EVA is usually used in the form of expanded plates, used in the stamping process for the manufacture of soles, insoles or various articles such as visors and toys [10,11]. The wide range of EVA applications is due to good resistance to ozone attack, weather resistance and excellent mechanical properties [12]. ...
Article
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The functionalization of the ethylene–vinyl acetate copolymer (EVA) was carried out in an internal mixer, using maleic anhydride (MA), dicumyl peroxide (DCP) and styrene monomer (St) as additives. Torque rheometry, Fourier transform infrared spectroscopy (FTIR), titration, gel content, thermogravimetry (TG) and differential scanning calorimetry (DSC) were evaluated. The EVA/MA/DCP and EVA/MA/DCP/St torque curves showed a significant increase, indicating the cross-linking process. FTIR confirmed the appearance of a new band in the EVA chain, at 1780 cm−1, attributed to the carbonyl group of maleic anhydride. However, maleic anhydride grafting to the EVA/MA/DCP system only occurred for the 5% MA/0.3% DCP ratio. When the EVA/MA/DCP system is additivation with the styrene monomer (St), all compositions grafted maleic anhydride into the EVA chain, suggesting that styrene increases the effectiveness of the degree of grafting. In addition, FTIR indicated the emergence of a band at 702 cm−1, due to the vibration of the aromatic core of styrene and, therefore, forming a multiphase copolymer (EVA-g-(St-co-MA)). The thermal stability was practically not altered when functionalizing the EVA with maleic anhydride, as verified by TG. The crystalline melting temperature, the crystallization temperature, the enthalpy of crystalline melting and the degree of crystallinity decreased with the EVA functionalization process. In general, a high degree of grafting of maleic anhydride in the EVA chain is difficult, due to the competitive effect with the cross-linking process.
... When Eva scraps are recycled in polymeric matrices, conventional processes are adopted. In the footwear industry, the recycling potential of these compounds has been investigated via mechanical properties [13,14]. Knowledge of the rheological properties of rubber products is important to optimize its commercial production, however few works can be found addressing rubber waste added to footwear rubbers. ...
Preprint
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Ethylene vinyl acetate blends (EVA-B) (at 19 and 28wt% vinyl acetate) were supplied by the footwear industry, along with an industrial (reference) compound labeled EVA-ref. EVA waste is an industrial sub-product crosslinked (injection sprues and unused midsoles), that was particulate through a micronization process and labeled as EVA-w. The objective of the present work was to evaluate processability and rheological parameters (using torque rheometry) when adding EVA-w to EVA-B. The EVA-w particle size distribution was bimodal, with an average diameter of 53.06 μm, and volume (%) D (10), D (50), and D (90) respectively equal to 12.47, 31.83, and 135.18 μm. However, this ample size distribution did not affect the composite mixing. FTIR-ATR analysis showed that no new crosslinking occurred after processing the composites. Low unit mixing energy (Wu), and mechanical work (as represented by DT values: torque stabilization temperature (T stab ) - test temperature (T test )) were required to mix the composites. Consequently, the dispersion of the EVA-w particles within the molten EVA-B occurred during the first 3 min of mixing, making it easier. The sensibility to shear-thinning behavior was more pronounced when adding EVA-w, especially at 25 phr. The m parameter was smaller in the composites as compared to the EVA-ref, and when adding EVA-w at 35 phr, it showed a tendency to increase. The average shear stress (E) of the 15 phr composite was similar to that of the EVA-ref compound. Yet for 25 phr, a higher value was observed. The adding of EVA-w made the non-Newtonian behavior of EVA-B less pronounced. For all samples, the average viscosity (t) decreased with average shear rate (h), revealing a pseudoplastic behavior.
... Among the most widely used synthetic rubbers are styrene-butadiene, ethylene-propylene, and silicone rubbers. The elastomeric properties of rubber along with their chemical resistance, is used in countless applications in the industrial sector, such as in tires, footwear, pipes, transmission belts, or parts for fluid sealing [4]. ...
Article
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A large amount of discarded tire waste generated year after year has encouraged the scientific community to seek alternatives for recycling or reusing this waste. The cross-linked nature and the high number of additives in tires make recycling significantly difficult. Thus, the use of particulate rubber as filler for other materials such as concrete has emerged as an attractive alternative. However, the hydrophobic nature of the rubber and hydrophilic particles of cement decreases the compatibility at the cementitious matrix-rubber interface, affecting the concrete's final performance. This work presents a method based on hydrogen peroxide and Fenton for the oxidation of rubber particles from end-of-life tires to introduce hydrophilic groups on the surface of the particles to improve compatibility at the interface. The method was studied from an experimental design approach based on the infrared spectroscopy response and using a Rechtschaffner Resolution V design, PCA and PLSR in order to evaluate variables such as time, temperature and reactants. The concentration of H2O2 and reaction temperature was shown to increase the oxidation, while Fenton reduces the time of oxidation.
... laptops and mobile phones, pipes, children's toys e.g. Legos, personal protective equipment and helmets (Makria, et al. 2019, Keenan, 2018 C Thermoplastic polymer (Keenan, 2018); (C 8 H 8 ) x , terpolymer made by polymerizing styrene and acrylonitrile in the presence of polybutadiene; Very durable, stiff, and strong C Inability to withstand ultraviolet radiation from the sun C Glass transition temperature ¼ 105 C; no true melting point due to amorphous C ABS can be used between -20 and 80 C C Non-Biodegradable Ethylene vinyl acetate (EVA) Footwear industry, including soles and insoles (Lopes et al. 2015) C Linear molecular structure, specific gravity ¼ 0.92, processing temperature ¼ 65-80 C (Sengoz and Isikyakar 2008), melting flow index ¼ 2.5 g/10 min (Mansourian et al. 2019) C Provides the modification of asphalt via a crystallization of rigid 3-D networks resulting in a considerable change in physical, chemical, and morphological properties of asphalt (Gad et al. 2010) C Non-biodegradable Polycarbonate (PC) CDs and DVDs (continued on next page) ...
Article
Current practice of recycled waste plastics includes 7 major types: polyethylene terephthalate (PETE), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), and others such as acrylonitrile butadiene styrene (ABS), ethylene vinyl acetate (EVA), polycarbonate (PC), and polyurethane (PU). This paper provides a comprehensive and in-depth literature review on the feasibility and the state-of-art repurposing waste plastics into cleaner asphalt pavement materials. Optimum dosage of waste plastics should be identified based on appropriate engineering performance parameters such as viscosity of asphalt, and rutting, fatigue cracking, thermal cracking, and moisture resistance of asphalt mixtures. If the appropriate amount of plastic is not determined, adverse impacts on the performance of the pavement could occur. Plastic wastes are incorporated into asphalt mixes by the dry (aggregate substitute) or wet (binder modifier, extender, or substitute) methods. In general, the incorporation of plastic wastes into asphalt mixes showed improvements in performance parameters such as stiffness, and rutting and fatigue resistance. However, HDPE, PVC, LDPE, PP, and PS yielded conflicting performance measures. Overall, the capability of recycling waste plastics into asphalt mixes would minimize landfilling, reduce dependence on nonrenewable resources, and diversify asphalt pavement building options. Additional research is needed to fully understand the effects of various plastics on the performance of the pavement, and potential environmental and economic impacts this process could implicate. Another area where further study is needed are methods to improve the compatibilization between plastic and asphalt.
... Finally, the university-company-state relationship could support environmental actions in the sector to improve corporate sustainability performance, e.g. conducting research and development and finding alternatives for the recovery of materials, as was done for the recycling of cuts of EVA from templates in the manufacture of light concrete (Lima, Leite, and Santiago 2010) and the development of natural and synthetic compounds for sustainable application in the footwear sector (Lopes et al. 2015). Moreover, industrial symbiosis could be developed from industrial ecology (von Hauff and Wilderer 2008), as was the case with rubber in Malaysia (Sharib and Halog 2017). ...
Article
Given the growing global demand for footwear, its increasingly shorter life cycle, the billions of pairs of shoes sold and the negative environmental impacts in the shoe supply chain, this paper explores the negative environmental impact in the stages of the life cycle of leather dress footwear and proposals to reduce them, taking the process of manufacturing handmade women’s leather dress shoes in small Colombian companies as an example. The MET (material, energy, toxicity) matrix was used for the qualitative life cycle analysis along with information from unstructured interviews and from observing the production process. The actions to reduce environmental impacts were processed via a systematized information search. The results show that production and end of life stages have the greatest impacts, and actors in the supply chain must be integrated to effectively manage the materials. Furthermore, proposals to reduce negative environmental impacts were presented as a way to improve environmental performance.
... Lopes et al. [79] studied the production of natural and synthetic rubber/waste-ethylenevinyl acetate (EVA) composites using natural rubber, styrene-butadiene rubber or acrylonitrile-butadiene rubber and 10-20 parts per hundred rubber (phr) of waste. Several physical and mechanical properties of the composites were further determined according to the requirements of the footwear sector, confirming the possibility to reintroduce part of raw material recycled from EVA-waste in the footwear industry. ...
Chapter
The footwear production in the world exceeded more than 21 billion/pairs in 2017. The largest producer (11.4 billion/year) and exporter (8 billion/year) is China, manufacturing a wide variety of models and being USA its main purchaser. Brazilian footwear production was 950 million/pairs in 2019, corresponding the fourth largest production in the world. While Brazilian footwear is mainly focused on national market (around 87% of the production), the first three largest manufacture countries (China, Vietnam and Indonesia) aim at exporting their products to European and North American brands. This study aimed to verify the panorama and the sustainable solutions being carried out by Brazilian footwear sector. The methodology was based in literature research and informations provided by Brazilian companies. Brazilian footwear industry is finding solutions to reduce production costs in order to diversify shoe models and compete in the international market. One of the strategies is the gradual replacement of leather by fabrics, synthetic polymers and rubbers. In 2017, the correspondent amounts were: 49.0% plastic/rubber; 28.8% synthetic laminate; 17.7% leather and fabrics—only 4.5%. Another important issue to reduce cost and distance is the cluster agglomeration, whose there are 13 clusters in 6 Brazilian states. The employment of natural fibers in footwear corresponds to a small part in comparison of synthetic fibers. Cellulosic fibers are being researched as biodegradable materials, showing innovations for instance, the use of leather waste, coconut fiber and latex, multilayers fabrics and finishing process adding bactericide properties to cotton. Particularly, the employment of cotton, raffia and jute fabrics outstands in footwear summer collections. However, more consistent initiatives related to the research of alternative materials, waste reduction, reuse and recycling are being carried out. New standards in waste disposal have forced major changes in production processes, and national seals also have been supporting these initiatives to manage processes in shoe, components factories and tanning. There are alternatives to chromium in tanning employing vegetable tannin. In addition, the design conception assists the durability increasing and post-consumption recycling easiness of its components, for instance reducing the number of components through digital fabrication. Thus, the increasing of researches about recycling footwear components and the development of biodegradable materials and processes points a sustainability trend in this sector.
... Singlecomponent thermoplastic hardens from molten state after cooling from elevated temperatures (Groover, 2010 Since the creation in 1970's, the most popular soles are Ethylene Vinyl Acetate (EVA) soles (Wang et al., 2012;Fuss et al., 2014). A large range of articles using EVA are being produced for the footwear industry (Lopes et al, 2015). Ethylene Vinyl Acetate is polymer based copolymer consisting of ethylene and vinyl acetate (Shi et al., 2008; Brito e Dias et al., 2018), also called expanded rubber or foam rubber, Figure 1. ...
Article
Since 1970’s, the most popular shoe soles are (EVA) soles, made from Ethylene Vinyl Acetate, copolymer consisting of ethylene and vinyl acetate. The thermosets and elastomers (rubbers), among them accounting EVA, encompasses around 30% of the tonnage of all synthetic polymers produced, with the synthetic rubbers exceeding the tonnage of natural rubber. With that in mind, the energy savings in rubber processing plants are of great importance and the paper analyses the potential of energy savings in shoe soles production process made of Ethylene Vinyl Acetate (EVA). The shoe soles made from EVA are lightweight, easy to mould, water and moisture resistant, highly elastic, shock absorbent, great thermal insulators, highly durable, etc. The energy savings using the process return condensate in shoe sole production process are presented. Using the return condensate results in lower make up water consumption, substantial fuel savings needed to produce steam and lower chemical consumption. Returning hot process condensate to the boiler results in oil savings of 14,9%. Also, the thermal pollution is reduced by 95,3%, while the volume of the flue gases is lowered from 17,11 m3FG/kgNEC to 14,57 m3FG/kgNEC or by 14,8%. Such a system enables both the oil savings and reduces the thermal pollution. The comparison of process with and without flue gases heat recovery shows fuel savings of 18,76%, while the temperature reduces from 221°C to 137,39°C and while the volume of the flue gases is lowered to 13,90 m3FG/ kgP.
... SMW, which usually consists of hard-to-separate rubbers, fabrics, and cellulose-based and wood materials at varying quantities [4][5][6][7], is usually classified as low-value organic waste with variable high ash and moisture content 1 3 [5,6] and is often disposed of in landfill [1,8]. However, given the increasing environmental concerns of landfill and severe shortage of suitable landfill sites, finding alternative solid waste management strategies with potential socioeconomic benefits has received ever growing attention. ...
Article
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The ash formation behaviour and associated compositional characteristics of the combustion of shoe manufacturing waste (SMW) in a 2.5 MWth pilot-scale circulating fluidized bed combustor (CFBC) were investigated to better understand the combustion behaviour and to find effective management strategy for the disposal of the ash streams produced. The compositional characterisations for the ashes produced from the pilot demonstrations showed the presence of a variety of trace heavy metals both in the fly ash and bottom ash. A pronounced uneven partitioning behaviour was observed on the distribution of these heavy metals between the fly ash and bottom ash, and it was found that all the heavy metals except chromium were preferentially enriched in the fly ash, with the contents of lead and cadmium in the fly ash being over 11 and 6 times higher than in the bottom ash. Leaching tests demonstrated that the concentrations of most of the aforementioned metals present in the leachates from the fly ash and bottom ash could meet the permissible limits for landfill disposal but with lead as an exception with its concentration in the fly ash leachates being over 2 times higher than the limit. The total PCDD and PCDF contents both in the fly ash and bottom ash were also much below the legal limit. To further understand the ash behaviour, the slagging and fouling tendency during SMW combustion in the CFBC was examined by use of the characterisation of the ash mineralogy and the results indicated that the SMW ash likely had low tendencies for slagging and fouling. The best two valorization routes for the SMW bottom ash and fly ash were recommended, one being to use them to produce colloidal silica medium to obtain safe inert filler and the other being to use them as the raw materials in the cement industry. Graphic Abstract Open image in new window
Article
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Samples of ethylene vinyl acetate (EVA) co‐polymer foams in form of plates and industrial outsoles of prototyped sport shoes containing 0% (reference), 2.5%, and 5.0 weight % (wt%) of hollow glass microspheres (HGM) were made. The goal was to study the influence of HGM on properties of EVA foam in laboratory conditions followed by the industrial trial, where the most promising laboratory result was applied. The physical properties of samples and behavior of material under dynamic load were examined. EVA foams with HGM filler demonstrated that they have better ability to reduce impact peak force and increase absorb impact impulse compared to the reference foam without HGM. Addition of 5.0 wt% of HGM in laboratory foam increased its absorbed impact pulse by two‐fold. Meanwhile for industrial prototype outsoles, the impact peak force was reduced by 5%–7% in walking simulated conditions and by 11% in case of simulated running. It is also observed that, addition of 5.0 wt% of HGM in EVA foam increased its abrasion resistance by three times, which generally helps to increase the lifetime of sport footwear. Under dynamic load, samples with the addition of HGM behave interestingly and result shows a small decrease in energy return (7%) which is logical, because this composite tends to absorb energy and not return it. Samples with 2.5 wt% HGM are stiffer than reference until 40% compression deformation, but beyond that point it becomes softer, and better absorbs impact energy than reference. Outsole with 2.5% of HGM in EVA outsole increased resistance of shoe at lateral bending of 50% and 20% rise of resistance was found at medial twist. Impact absorption and flexibility resistance are useful for protection against impact which are also helpful to prevent sport injuries. The obtained results show the addition of HGMs which are cheap by‐products in several technologies brings improvement to properties of EVA foams which is the most common materials for the sport footwear industry.
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Polyurethanes are one of most versatile and large class of polymer because of its wide range of applications. The products of polyurethane are innovative and life-enhancing that play a unique role in making the world more sustainable and can help to solve some of the world’s biggest challenges. Most of the polyurethane products and components are durable and long lasting due to its unique chemical structure. To a large extent, the characteristics of the polyurethane are determined by the chemical nature of the building blocks and modification by the addition of the components in the backbone chain of the polymer. This review summarises the synthesis of polyurethanes using different polyols and pre-polymers from renewable feedstock and modification by maleic anhydride via different synthetic routes for various industrial applications like paints, adhesives, foam, coatings, inks, leathers, toys, automotive, packaging, dispersions, hydrogels, composites, construction etc. The objective of this review is to provide a comprehensive, informative, valuable and critical summary about the current development in the field of maleic anhydride-based polyurethanes. Generally polyurethane synthesized from Renewable as well as petrochemical sources but Polyurethane from Renewable resources is most explored transformation in polymer chemistry. This review highlights the most recent developments in the role of maleic anhydride in polyurethane synthesis from renewable feedstock/ starting material.
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Natural rubber latex (NRL) has prophylactic properties and is used to make pathogen-isolating products like condoms and surgical gloves. However, obtaining NRL and casting it into durable products are challenging. Consequently, progress in the research and development of medical NRL products has been slow. This study aims to strengthen NR and induce it with bactericidal properties. In this regard, we introduce inorganic whiskers into the NRL and synthesize whiskers/NR composites with strong mechanical and antibacterial properties. The method proposed herein is a template method, which can rapidly and efficiently reveal the antibacterial effect of the composite latex, providing convenience for research institutions and factories studying antibacterial latex. A complete system is established for studying the antibacterial medical NRL, and a precedent is set for the relevant products.
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Dynamic disulphide exchange mechanism was introduced to promote self‐healing characteristics to natural rubber compound and the corresponding healing mechanism and mechanical properties are presented. The formation of reversible dynamic disulphide bonds within rubber molecular chains was evidenced via FTIR and the total crosslink density of dynamic disulphide crosslinks was quantitatively measured by equilibrium swelling test. Scanning Electron Microscopy (SEM) results revealed that the healed area of the fractured surface adhered well with minor scar on the contact surface, suggesting that intermolecular diffusion occur at the fracture surface. It was also found that the tensile strength and tear strength of the broken samples able to recover 91% and 103%, respectively, under thermal healing at 150°C for 10 min. The fatigue lifespan of the materials increased 154.9% compared with the conventional rubber. The successful fabrication of self‐healing natural rubber through dynamically reversible disulphide exchange mechanism would be expected to open up new opportunities for development of sustainable rubber products.
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Response Surface Methodology (RSM) and the Normal Boundary Intersection (NBI) method were utilized in this study for modeling and multi-objective optimization of carbonized wood/silicon dioxide composites. Operational variables such as particle size, carbonization temperature, filler content, curing temperature, curing pressure, and curing time were simultaneously adjusted to improve the tensile, hardness, density, and water absorption characteristics of the composite. RSM models were developed utilizing an experimental approach based on the Central Composite Design (CCD). The models showed outstanding correlation coefficient, with a threshold of 0.9959 and was therefore employed as the fitness function for the NBI algorithm's multi-objective optimization. A set of optimal compromise solutions was found at 25 µm particle size, 200 oC carbonization temperature, 51 phr filler content, 150 oC curing temperature, 3 Pa curing pressure and 10 min curing time; this formular results in 19.22 MPa tensile stress, 1.08 g/cm³ density, 97.15 hardness (shore A) and 7.18% water absorption. The optimum material formular was then deployed in single-density shoe sole manufacturing using a predesigned steel mould. Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were used to characterize the new material.
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The paper is an analysis of the experimental and theoretical behavior of cementitious plate containing waste ethylene vinyl acetate (EVA) with and without reinforcement with glass fiber woven fabric (GFRP) under low-velocity impact load effect. Cementitious plates of 150 mm × 150 mm size and three different thicknesses (15 mm, 30 mm, 50 mm) are produced by replacing the cement mixture aggregate with EVA at 0%, 18%, 32%, 45%, and 56% by volume of aggregate. Then, the cementitious plates are coated with GFRP using vacuum infusion method. The effect of EVA and GRFP coatings on the dynamic impact behavior of cementitious plates is investigated by applying a low-velocity impact test on the produced cementitious plates with an impactor of 18 mm diameter, 10.50 kg weight, and 500 mm height. The data obtained from the experimental results are analyzed based on the mass-plate theory, lightweight (LWC) and normal weight (NWC) concrete, and the consistency of the theoretical results with the experimental results is compared. It has been determined that the use of NWC is more suitable for cementitious plates with an EVA replacement rate in the range of 0–32%, while the use of LWC offers more optimum results if the EVA ratio is in the range of 32–56%. Especially when the EVA displacement exceeds 32%, it causes excessive void formation in the structure, resulting in a reduction in the dynamic impact loads of cementitious plates. GFRP coating with vacuum infusion method is not recommended for cementitious plate structures when the EVA replacement rate exceeds 32% by volume of aggregate.
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Soft and conductive interfaces are valuable in wearable electronics as they are capable for integration of diverse classes of electronic and sensor technologies directly with living body which can be used as health monitoring systems. In present work, we explore the development of multi-walled carbon nanotube-ethylene vinyl acetate nanocomposite (MWCNT-EVA) film and their properties. Oxidation of MWCNT is known to improve their dispersion properties and increase the electrical conductivity of MWCNT-polymer nanocomposites. Thus, pristine MWCNTs (p-MWCNTs) and functionalized MWCNTs (f-MWCNTs) were further used as conductive filler to construct p-MWCNT-EVA and f-MWCNT-EVA nanocomposite films. The films were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis and electrochemical technique. The results indicated that the chemical oxidation of p-MWCNT generates carboxylic function at the p-MWCNT surface important for sensor fabrication. The concentration of carboxylic functional group in f-MWCNT higher than in nanocomposites. The f-MWCNT-EVA nanocomposite film electrode surface show much higher conductivitythan p-MWCNT-EVAnanocomposite film. Thus, the soft and flexible f-MWCNT-EVA nanocomposite films are effective for the development of electrochemical platform for biosensor fabrication in wearable applications.
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Due to the complex composition of the rubber compound, the optimization of the formulation for its preparation is a complex process. The experiments required to determine the optimal composition are a multi-step process that requires time and money. The purpose of this article is to use the method of mathematical modeling to determine the optimal composition of a rubber compound with the addition of industrial waste. Sulfur of the Tengiz deposit and metallurgical production slags were used as industrial waste. The Protodyakonov equation was used to derive the generalized equation and check its adequacy. The escaped equations were used to prepare the rubber compound. The process of vulcanization of the mixture with and without the addition of waste was carried out. The kinetics of vulcanization of the optimized mixture has been studied. The optimized composite provides higher minimum and maximum torque levels, shorter initiation times and optimal cure times compared to a blend without additive. Tensile tests have shown that the composition of the rubber compound, selected by the method of mathematical modeling, is not inferior to the standard formulation. The computational model for determining the optimal composition of the rubber compound can be used for research and applied purposes in various industries related to rubber.
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In this study, natural rubber/ethylene vinyl acetate (NR/EVA) blends are formulated by simple blend using two roll mill. The set properties, both compression and tension, are evaluated as a function of NR/EVA ratios. The ratio of NR/EVA ranges from 100/0 to 95/5, 90/10, 85/15, and to 80/20. Compression and tension set are performed on vulcanized rubber samples at ambient and elevated temperature (100 °C) with constant compression or elongation at 25% of initial value. All tests are carried out for 72 h. Air‐circulated oven is used to conduct testing at elevated temperature. Crosslink density before and after testing is also monitored by equilibrium swelling method. Tensile properties and hardness are also measured to support the discussion. The results show that compression and tension set at ambient temperature tend to increase upon the EVA concentration in the formulation. Set properties are independent of EVA concentration at elevated temperature. Incorporation of EVA decreases the rebound resilience property and thermal aging tends to increase it. The rebound resilience ranges from 31% to 40% for original samples, and from 33% to 43% for aged samples.
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Conference Paper
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RESUMO Atualmente verifica-se a crescente preocupação com o meio ambiente, bem como o uso de recursos renováveis, a reciclagem e reutilização de resíduos, principalmente os originários de processos industriais gerados em grande quantidade em paralelo ao desenvolvimento industrial. A produção de calçados, denominada cadeia calçadista, por apresentar muitas etapas e diversificados tipos de insumos e recursos utilizados, apresenta uma gama interessante de oportunidades para o uso de ferramentas ambientais e estudos de caso que contribuam positivamente para a redução dos impactos ambientais gerados por este processo produtivo. Ao longo dos últimos 20 anos, o setor do calçado tem se empenhado em direcionar esforços significativos para melhorar a eficiência do uso de materiais, assim como a eliminação da utilização de materiais perigosos durante as fases de produção. No entanto, os ganhos ambientais feitos na produção estão sendo ultrapassados pelo impacto negativo do aumento considerável na demanda destes produtos com o uso de uma gama muito grande de diferentes materiais e tratamentos superficiais. Este artigo tem por objetivo apresentar ao setor calçadista e sua diversidade de materiais, a aplicação da análise do ciclo de vida como ferramenta para estratégia de gestão de resíduos do setor. Palavras-chave: indústria calçadista, resíduos, análise do ciclo de vida. ABSTRACT The environment and the use of renewable resources, waste recycling and reuse, mainly originating from industrial processes, which are generated in large amount in parallel to industrial development has been seen as a growing concern. The production of shoes, named footwear chain, which presents a range of environmental tools opportunities and study cases to reduce the environmental impacts generated by this production process seems to be interesting due to its many stage of production and diverse types of used inputs and resources. Over the past 20 years, the footwear industry has put considerable effort to improve the material use efficiency as well as eliminating the use of hazardous materials during the production stages. However, environmental gains made in production are overcome by the negative effect of a considerable increase in the demand for footwear products using a very large range of different materials and surface treatments. This article aims to present the footwear sector and its diversity of materials the application life cycle analysis as a tool for industry waste management strategy.
Thesis
This manuscript presents the synthesis of new elastomeric materials based on natural rubber derived building blocks and organic monomers having antifouling and/or antibacterial properties, covalently bound to the polymer network. Original acrylate monomers bearing an organic bioactive moiety (a Guanidinium group or Zosteric acid derivates) were synthesized and co-polymerized with telechelic acrylate oligomers from polyisoprene. No significant leaching of the bioactive monomers occurred and the material resisted to long water immersions. Freestanding films prepared from acrylate oligoisoprenes also showed a weak antibiofouling activity which was drastically increased by integrating the guanidinium and the Zosteric acid monomers. The coatings were active against several strains of pathogenic bacteria among which Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis and Staphylococcus epidermidis. In order to covalently graft oligoisoprenes to surfaces, new bifunctional oligoisoprenes bearing an alkoxy-silane end moiety were designed and coupled with silicon-containing materials. An alternative approach was followed by prefunctionalizing the surface with amino groups and by covalently grafting oligomers with carbonyl chain-ends. Post-polymerization from the surface free chain-ends resulted in a thick oligoisoprene coating with strong resistance to solvent immersion (water, THF). In this way, we were able to build dense and tethered molecular layers, thin films and thick coatings.
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Rubber blends containing nitrile rubber (NBR) and ground ethylene-vinyl acetate copolymer waste (EVAW) from the footwear industry have been prepared over a wide range of composition (up to 90 phr of waste component). The ground EVAW had particle size in the range of 100-350 mm and a gel content of 60±5%. The effect of different amounts of EVA waste on the tensile strength, elongation at break, hardness, tear strength and dynamic mechanical properties was studied. EVAW had a good reinforcing effect on the NBR matrix. A combination of optimum tensile properties, resistance to solvent penetration and dynamic mechanical properties, such as storage modulus and loss tangent was achieved by introducing 50 phr of EVAW in the NBR matrix. This composition also presents a more uniform morphology, as indicated by scanning electron microscopy.
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The worldwide consumption of footwear is estimated to be in excess of 20 billion pairs of shoes per year. To date very little work has been done to develop material recycling solutions for mixed footwear products. In fact less than 5% of end-of-life shoes are being recycled, with most being disposed of in landfill sites around the globe. One of the primary reasons is that most modern footwear products contain a complex mixture of leather, rubber, textile, polymers and metallic materials, that makes it difficult to perform complete separation and reclamation of material streams in an economically sustainable manner. This paper discusses the development of an economically feasible automated material recycling process for mixed postconsumer footwear waste. Central to this process are bespoke air-based separation technologies that separate granulated shoe particles based upon the difference in size and weight. Experimental studies with three different types of postconsumer footwear products show that it is possible to reclaim four usable material streams: leathers, textiles, foams and rubbers. For each of the reclaimed materials there are a variety of applications such as surfacing materials, insulation boards and underlay products.
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The EVA waste (EVAR) is a crosslinked material, which can be used as filler in rubber compositions. In this work, rheological and dynamic properties of natural rubber (NR) compositions with EVAR were investigated before and after vulcanization with the help of a rubber processing analyzer (RPA). The filler content varied from 0 to 60 phr. The results showed that rheological properties of nonvulcanized compositions were clearly modified by the addition of EVAR, which contributed to an increase in viscosity. The modulus relaxation and the dynamic properties such as tan δ of vulcanized compositions were also affected, by the reduction of the elasticity of the compositions. The mechanical properties corroborated the behavior revealed by RPA analysis and indicated that EVAR acted as a non-reinforcing filler.
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It has long been an accepted fact that the properties of vulcanized rubber articles are not uniform in all directions. Vulcanized rubber is, in general, an anisotropic material, and the results obtained from tests vary, to a greater or less extent, with the direction in which the strain is applied or the measurements are made. In much experimental work elaborate precautions have been followed whereby replicate samples have been taken in the same directions from the rubber material. The cause of anisotropy has always, as far as the authors are aware, been attributed to the methods of processing or shaping the raw stock. This is the view taken by the authors of one of the most recent publications. As calendering is an operation that produces an extreme distortion of the raw stock, such processing effects are considerable, and the resulting anisotropy has been known for many years as calender grain, or in appropriate cases, as extruder grain. It has been evident, however, for some years that the theory that the method of preparation of the raw stock is the sole or even the major cause of anisotropy is not adequate to explain certain phenomena. Some products exhibit pronounced anisotropy, although their method of preparation does not involve much distortion of the raw stock, and in other cases, such variation in properties as does exist does not give any correlation with the direction of processing. Consideration of cases such as these have led to the conclusion that the movement of the stock during moulding is an important factor in the problem, and one that, as far as can be seen from the literature, has been hitherto neglected.
Chapter
Shoe mass is important, since extra mass will add to the energy consumption of the athlete. Elite athletes use lightweight shoes (0.1 kg) for races, but heavier, more durable shoes for training. This chapter concentrates on trainers, which weigh about 0.3 kg. The main component parts of a shoe are: rubber outsole, foam midsole foam, foam innersole with cloth cover, heel counter, and top cloth. An old pair of trainers can be cut in half with a band-saw, to reveal the thickness of the various components. The midsole foam molding is wedge shaped and runs the entire length of the shoe, while traditional shoes would have a separate heel block. Sales appeal depends on brand names, and on the external shape and colors. The external appearance and even tread pattern have distinctive designs that emphasize real or imaginary internal components, which provide cushioning or control torsion of the foot. The majority of the cushioning is due to the Ethylene/Vinyl Acetate (EVA) midsole foam.
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Using the renowned shoe manufacturing sector in Marche Region (Italy) as a case-study, this paper deals with the characterisation of (1) the chemical and physical properties of representative types of shoe manufacturing wastes, (2) the quality profile of a particular material recovery finalised to a soil destination, and (3) the flue gas emissions from burning tests in view of the potential for energy recovery. The property characterisation has primarily revealed the following aspects: a general condition of resulting higher ash contents in shoe waste materials having a mineral or synthetic processing origin; and relatively high energy contents, ranging on the whole expressed as LHV (lower heating value) from 15,710 kJ kg−1 (for vegetable-tanned leather dust) to 42,439 kJ kg−1 (for natural rubber). The characterisation of a fertiliser that can be generated from the particular waste type of vegetable-tanned leather dust has determined an interesting quality profile classifiable as organic-nitrogen fertiliser with acceptable values of the humification parameters and heavy metal contents significantly below the assumed quality limits. Finally, simplified pilot-scale burning tests have provided the following findings: higher NOx emissions produced from leather-based materials as compared with the cellulose-based material, which are likely attributable to the substantial “fuel nitrogen” content of the original animal skins; higher HCl emissions produced from the leather-based materials in comparison with the cellulose-based material; and a more even combustion process occurred for the leather dust than for the other shoe materials.
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Composite materials are used in a wide range of applications such as automotive, aerospace and renewable energy industries. But they have not been properly recycled, due to their inherent nature of heterogeneity, in particular for the thermoset-based polymer composites. The current and future waste management and environmental legislations require all engineering materials to be properly recovered and recycled, from end-of-life (EOL) products such as automobiles, wind turbines and aircrafts. Recycling will ultimately lead to resource and energy saving. Various technologies, mostly focusing on reinforcement fibres and yet to be commercialized, have been developed: mechanical recycling, thermal recycling, and chemical recycling. However, lack of adequate markets, high recycling cost, and lower quality of the recyclates are the major commercialization barriers. To promote composites recycling, extensive R&D efforts are still needed on development of ground-breaking better recyclable composites and much more efficient separation technologies. It is believed that through the joint efforts from design, manufacturing, and end-of-life management, new separation and recycling technologies for the composite materials recycling will be available and more easily recyclable composite materials will be developed in the future.
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The impact performance of chopped bagasse–EVA matrix composites is evaluated and compared with the behavior of bagasse filled PP and PE matrix composites and wood-based materials. The volume fraction and size of the chopped bagasse used as filler was varied. The experimental results show that the incorporation of bagasse strongly reduces the deformation capacity of EVA polymer. The reduction of the deformation capacity of the composites was also inferred by solid-state NMR relaxation analysis. The impact strength was independent of the bagasse size, but varied with the volume fraction. As a function of the volume fraction it was shown that the mechanical performance of bagasse–EVA composites could be tailored to reproduce the behavior of wood-based particle boards.
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Fibre reinforced polymer (FRP) materials are being increasingly used in several applications, but especially in the construction and transportation industries. The composites industry is now producing a wide range of FRP products that include strengthening strips and sheets, reinforcing bars, structural profiles, sandwich panels, moulded planks and piping. The waste management of FRP materials, in particular those made with thermosetting resins, is a critical issue for the composites industry because these materials cannot be reprocessed. Therefore, most thermosetting FRP waste is presently sent to landfill, in spite of the significant environmental impact caused by disposing of it in this way. Because more and more waste is being produced throughout the life cycle of FRPs, innovative solutions are needed to manage it. This paper first presents a state-of-the-art review of the present alternatives available to manage FRP waste. It then describes an experimental study conducted on the technical feasibility of incorporating the fine waste generated during the manufacturing of glass fibre reinforced polymer (GFRP) composites in concrete mixtures. Tests were carried out to evaluate the fresh-state and hardened-state properties of concrete mixes in which between 0% and 20% of sand was replaced by GFRP fine waste. Although the incorporation of high proportions of GFRP waste was found to worsen concrete performance in terms of both mechanical and durability-related properties, it seems feasible to incorporate low proportions and reuse GFRP fine waste in concrete, particularly in non-structural applications such as architectural concrete or pavement slabs, where good mechanical properties are less important.
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Poly(ethylene-vinyl acetate) (EVA) copolymer was melt grafted with maleic anhydride (MAH) in a twin screw extruder in the presence of peroxide. It is confirmed that MAH has been melt grafted on the backbone of EVA by FTIR using the method of hydrolysis. The NMR analysis suggests that the grafting reaction occurs on the tertiary carbon of main chain of EVA other than the methyl moiety of vinyl acetate (VA) group. The incorporation of VA groups onto the matrix shows a competitive effect on the grafting. The existence of VA groups promotes the extent of MAH graft onto EVA; nevertheless, it also weakens the crystallizability of main chain. When the content of peroxide initiator is 0.1 wt % based on the polymer matrix, the grafting degree increases with increasing the concentration of monomer. When the peroxide content is higher than 0.1 wt %, side reactions such as crosslinking or disproportionation will be introduced into this system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 841–846, 2006
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Anisotropy and molecular orientation are well-known phenomena in the field of thermoplastics. In the case of rubber materials only a few studies have described anisotropy. Injection molding has been shown to give rise to higher anisotropy than compression molding. The anisotropy in the rubber material is assumed to be due to molecular orientation and is strengthened by carbon black. In order to understand the mechanism of anisotropy in rubber materials, an extensive study has been performed. In this paper, results from two injection-molded ethylene-propylene-diene (EPDM) rubbers, compounded both with and without carbon black, are presented. The polymers had different molecular weight distributions and the compounds were injected into center-gated 1- and 4-mm-thick disks. The properties measured in different directions were mechanical, dynamic mechanical, and swelling. These measurements show that anisotropy can be a very important factor to take into account. The origin of anisotropy is presumably the molecular orientation which arises during the filling of the mold with the rubber melt.
Article
Composites based on ethylene–vinyl acetate copolymers (EVA) functionalised with reactive groups (maleic anhydride, glycidyl methacrylate) and cellulose fibres (Cell) of different type were obtained by melt mixing, in the composition range 0–50 wt% Cell. The phase behaviour, the morphology and matrix–fibre interactions of the composites were analysed by DSC, DMTA, TGA, SEM and FT-IR spectroscopy. FT-IR analysis indicated the chemical interactions between the functional groups (MA, GMA) of EVA and the hydroxyl groups of cellulose. Accordingly, SEM microscopy pointed out an improved adhesion between cellulose and matrix in both EVA–MA/Cell and EVA–GMA/Cell composites, as compared to EVA/Cell composites. Glass transition behaviour and filler effectiveness (CFE) were analysed by DMTA. Tg of EVA and EVA–GMA changed markedly by the incorporation of cellulose. Cellulose was found to be more effective filler for EVA–GMA (CFE = 0.02) than EVA–MA (CFE = 0.22). Thermal resistance and tensile properties were significantly improved for GMA functionalised systems.
Article
In this paper two types of recycled aggregate, originated from construction and demolition waste (CDW) and ethylene vinyl acetate (EVA) waste, were used in the production of concrete. The EVA waste results from cutting off the EVA expanded sheets used to produce insoles and innersoles of shoes in the footwear industry. The goal of this study was to evaluate the influence of the use of these recycled aggregates as replacements of the natural coarse aggregate, upon density, compressive strength, tensile splitting strength and flexural behavior of recycled concrete. The experimental program was developed with three w/c ratios: 0.49, 0.63 and 0.82. Fifteen mixtures were produced with different aggregate substitution rates (0%, 50% EVA, 50% CDW, 25% CDW-25% EVA and 50% CDW-50% EVA), by volume. The results showed that it is possible to use the EVA waste and CDW to produce lightweight concrete having semi-structural properties.