Journal of Polymers and the Environment (J POLYM ENVIRON)

Publisher: Springer Verlag

Journal description

The Journal of Polymers and the Environment fills the need for an international forum in this diverse and rapidly expanding field. The journal serves a crucial role for the publication of information from a wide range of disciplines and is a central outlet for the publication of high-quality peer-reviewed original papers review articles and short communications. The journal is intentionally interdisciplinary in regard to contributions and covers the following subjects - polymers environmentally degradable polymers and degradation pathways: biological photochemical oxidative and hydrolytic; new environmental materials: derived by chemical and biosynthetic routes; environmental blends and composites; developments in processing and reactive processing of environmental polymers; characterization of environmental materials: mechanical physical thermal rheological morphological and others; recyclable polymers and plastics recycling environmental testing: in-laboratory simulations outdoor exposures and standardization of methodologies; environmental fate: end products and intermediates of biodegradation; microbiology and enzymology of polymer biodegradation; solid-waste management and public legislation specific to environmental polymers; and other related topics.

RG Journal Impact: 1.96 *

*This value is calculated using ResearchGate data and is based on average citation counts from work published in this journal. The data used in the calculation may not be exhaustive.

RG Journal impact history

2017 RG Journal impactAvailable summer 2018
2015 / 2016 RG Journal impact1.96
2014 RG Journal impact2.24
2013 RG Journal impact1.71
2012 RG Journal impact1.54
2011 RG Journal impact1.97
2010 RG Journal impact1.77
2009 RG Journal impact1.76
2008 RG Journal impact1.25
2007 RG Journal impact0.99
2006 RG Journal impact1.06
2005 RG Journal impact1.24
2004 RG Journal impact1.38
2003 RG Journal impact0.20
2002 RG Journal impact0.15
2001 RG Journal impact0.22
2000 RG Journal impact0.64

RG Journal impact over time

RG Journal impact
RG Journal impact over timeGraph showing a linear path with a yearly representation of impact points of the journal

Additional details

Cited half-life6.30
Immediacy index0.19
Eigenfactor0.00
Article influence0.42
WebsiteJournal of Polymers and the Environment website
Other titlesJournal of polymers and the environment (Online)
ISSN1566-2543
OCLC45848804
Material typeDocument, Periodical, Internet resource
Document typeInternet Resource, Computer File, Journal / Magazine / Newspaper

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Publications in this journal

  • The aim of this work was to evaluate the effect of different plasticizers on the morphology, crystallization, and mechanical properties of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)/organomodified montmorillonite (OMt) nanocomposites. We investigated three different plasticizers: dioctyl phthalate (DOP), a commonly used additive in the polymer industry, and two natural and biodegradable plasticizers: epoxidized soybean oil (ESO) and triethyl citrate (TEC). The nanocomposites with 3 wt% OMt were obtained by melt processing in an internal mixer. The plasticizers were used alone or in combination with clay in a concentration of 10 wt%. X-ray diffraction and scanning electron microscopy results revealed a partially intercalated structure. The degree of crystallinity was higher for all of the samples compared to neat PHBV, although the melting temperature decreased with the use of plasticizers combined with OMt. The impact strength results were dependent on the interaction between the components of the system. Triethyl citrate was the most effective plasticizer due to its more pronounced interaction with the PHBV matrix, which yielded improvements in processing conditions and PHBV’s flexibility and impact properties.
  • Aliphatic–aromatic polyols were synthesized by thiol–ene reactions (photochemical or thermal) using mercaptanized starting materials from bio-based compounds: limonene dimercaptan, thioglycerol, mercaptanized castor oil and isosorbide (3-mercaptopropyl) ether. Aromatic starting materials were phenols containing double bonds; ortho-allyl phenol (OAP, petrochemical-based) and eugenol (EUG, bio-based). The phenolic hydroxyl groups were blocked by alkoxylation with propylene oxide (PO) or glycidol (GLY) prior to use in thiol–ene reaction. The aromatic rings were attached to the mercaptans by reacting thiol groups with the double bonds of alkoxylated OAP (OAP–PO and OAP–GLY) and alkoxylated EUG (EUG–PO and EUG–GLY). These synthesized aliphatic–aromatic polyols were utilized for preparation of rigid polyurethane foams whose physical–mechanical properties were superior to those made only from bio-based aliphatic polyols. These rigid PU foams can be used in a wide range of applications; such as thermal insulation of freezers, buildings, pipes and storage tanks for food and chemical industries, as wood substitute, packaging materials and flotation materials.
  • Natural rubber (NR) with polycaprolactone (PCL) core–shell (NR-ad-PCL), synthesized by admicellar polymerization, was acted as an impact modifier for poly(lactic acid) (PLA). PLA and NR-ad-PCL were melt-blended using a co-rotating twin screw extruder. The morphology of PLA/NR-ad-PCL blends showed good adhesion as smooth boundary around rubber particles and PLA matrix. Only 5 wt% of rubber phase, NR-ad-PCL was more effective than NR to enhance toughness and mechanical properties of PLA. The contents of the NR-ad-PCL were varied from 5, 10, 15 and 20 wt%. From thermal results, the incorporation of the NR-ad-PCL decreased the glass transition temperature and slightly increased degree of crystallinity of PLA. Mechanical properties of the PLA/NR-ad-PCL blends were investigated by dynamic mechanical analyser, pendulum impact tester and universal testing machine for tension and flexural properties. The increasing NR-ad-PCL contents led to decreasing Young’s and storage moduli but increasing loss modulus. Impact strength and elongation at break of the PLA/NR-ad-PCL blends increased with increasing NR-ad-PCL content up to 15 wt% where the maximum impact strength was about three times higher than that of pure PLA and the elongation at break increased to 79%.
  • Due to its widespread use and water solubility, poly(vinyl alcohol) (PVA) has the potential to find its way into various water or soil ecosystems. Despite the fact that many bacterial species with the capacity of utilizing PVA have been found and described, the influences of some environmental factors on their capabilities to biodegrade PVA have not been adequately studied. Therefore, study was made of the effects of two environmental factors on PVA degradation exhibited by two Sphingomonas strains. Both strains originated from common wastewater treatment plants, and proved to be considerably sensitive to increased inorganic salt concentrations; in brief, 13.3 mmol/l either of phosphate or chloride ions significantly delayed the degradation process or inhibited it entirely. In contrast to such halosensitivity, both strains were able to rapidly utilize PVA under suitable conditions, even when low inoculum sizes were applied. Initial cell densities, ranging from 10⁰ to 10⁷ cells/ml, were used in two series of degradation trials and PVA degradation occurred in all cases; merely delays extending over several days in the degradation process were noted when inoculum sizes of 10⁰–10³ cells/ml were applied.
  • Chitin has been produced from different sea waste sources including, molluscs (mussel and oyster shell), crustacean (prawn and crab) and fish scale (pang and silver scales) using deproteinization and demineralization as chemical methods. The conditions of chemical extraction process determine the quality of chitin. The obtained results revealed that, about 1 and 10% HCl and NaOH were adequate concentrations for deproteinization and demineralization process respectively. Chitin from oyster and crab shell waste had the highest yield of 69.65 and 60.00% while prawn, mussel shell, pang and silver scales had the lowest yield of 40.89, 35.03, 35.07 and 31.11% respectively. Chitin solubility is controlled by the quantity of protonated acetyl groups within the polymeric chain of the chitin backbone, thus on the percentage of acetylated and non-acetylated d-glucos-acetamide unit. Good solubility results were obtained in mussel, oyster and crab shells respectively. The chitin molecular weight characteristics and activity are controlled by the degree of acetylation (DA) and the distribution of acetyl group extending in the polymer chain. DA is determined by acid-base titration methods and molecular weight determined by Brookfield viscometry. Both methods are found to be effective.
  • Chitosan–starch polymers are reinforced with different keratin materials obtained from chicken feather. Keratin materials are treated with sodium hydroxide; the modified surfaces are rougher in comparison with untreated surfaces, observed by Scanning Electron Microscopy. The results obtained by Differential Scanning Calorimetry show an increase in the endothermic peak related to water evaporation of the films from 92 °C (matrix) up to 102–114 °C (reinforced composites). Glass transition temperature increases from 126 °C in the polymer matrix up to 170–200 °C for the composites. Additionally, the storage modulus in the composites is enhanced up to 1614% for the composites with modified ground quill, 2522% for composites with modified long fiber and 3206% for the composites with modified short fiber. The lysozyme test shows an improved in the degradability rate, the weight loss of the films at 21 days is reduced from 73% for chitosan-starch matrix up to 16% for the composites with 5 wt% of quill; but all films show a biodegradable character depending on keratin type and chemical modification. The outstanding properties related to the addition of treated keratin materials show that these natural composites are a remarkable alternative to potentiating chitosan–starch films with sustainable features.
  • In this work, morphology, rheological and tensile properties of low-density polyethylene/linear low-density polyethylene/thermoplastic oxidized starch (LDPE/LLDPE/TPOS) blends are studied. The blends of LDPE/LLDPE (70/30, w/w) containing 0–20 wt% TPOS in the presence of 3 wt% of PE-grafted maleic anhydride (PE-g-MA) as a compatibilizer are prepared by a twin screw extruder and then converted to appropriate thin films using an extrusion film blowing machine. Scanning electron microscopic images show that there is a relative good dispersion of oxidized starch particles in PE matrices. However, as TPOS content in the blends increases, the starch particle size increases too. The rheological analyses indicate that TPOS can decrease the elasticity and viscosity of the blends. The LDPE/LLDPE/TPOS blends show power-law behavior and as the TPOS content increases the power-law exponent (n) and consistency index (K) decrease. The ultimate tensile strength and elongation at break of the final blend films reduce, when TPOS content increases from 5 to 20 wt%. However, the required mechanical properties for packaging applications are achieved when 10 wt% oxidized starch is added, according to ASTM D4635.
  • A novel Fe3O4/cellulose–polyvinyl alcohol (PVA) aerogel was successfully synthesized by an eco-friendly and facile method in this work. Cellulose/PVA matrix was prepared through an environmental friendly physical cross-linking process and further in-situ decorated with Fe3O4. Series of Fe3O4 decorated aerogels were prepared and the effects of Fe3O4 nanoparticles (NPs) on the aerogels were systematic investigated. As-prepared aerogels exhibited desirable properties including nanostructure, relatively high porosity, improved mechanical and superparamagnetism. The TEM results showed that Fe3O4 NPs were integrated in the three-dimensional matrix of cellulose/PVA with a diameter of 9–12 nm. Furthermore, the mechanical strength of the aerogels was significantly enhanced after the introduction of Fe3O4 NPs. Meanwhile, the obtained Fe3O4/cellulose/PVA aerogel exhibited excellent adsorption performance toward methyl blue dye, and can be reused through fenton-like catalysts oxidative degradation of organic dye in H2O2 solution. Therefore, they will have a great potential application as eco-friendly and economical adsorbents.
  • A new functional monomer based on vanillin was synthetized and used in the preparation of three different molar concentrations of temperature and pH responsive photo-cross-linker polymers via free radical polymerization with N-isopropylacryamide and malimide photo-cross-linker. Polymers were investigated by ¹HNMR, FTIR, UV, gel permeation chromatography (GPC) and differential scanning calorimetery (DSC). The non-responsive copolymers have been synthetized from N,N-dimemthylacrylamide with malimide. Lower critical solution temperatures (Tc) were determined by UV–Vis spectroscopy. Hydrogel bilayer was formed by spin coating of polymer solution of poly(N-isopropylacryamide-Co-malimide-Co-DEAMVA) layer A over gold with adhesion promoter, then cross-linked by UV-irradiation. The swelling properties were determined by surface plasmon resonance with optical waveguides (SPR/OW). The Tc of hydrogel was also determined as function of volume degree of swelling or refractive index with temperature at different pH. The next layer was formed by spin coating of polymer solution poly(N,N-dimemthylacrylamid-Co-malimide) layer B over layer A, then cross-linked by UV-irradiation. The swelling properties and Tc were determined by SPR/OW in different media. Our target is the formation of biosensor functional gel vessel for biological molecules using aldehyde group. The bilayer functional hydrogels will have an additional feature, in which the target molecule stays safely inside this gel vessel responsively temperature and pH.
  • Ketoprofen is an analgesic with potent anti-inflammatory activity against acute inflammation, subacute inflammation, for the acute and long-term treatment of various inflammatory pathologies, as rheumatoid arthritis and colonic adenocarcinoma. In order to minimize the incidence of systemic events related to ketoprofen, the transdermal drug delivery system development has been most important. The advantages of using natural rubber latex membranes include not only the reduction of adverse systemic events, but also the suitability of the low cost of the material together with its physicochemical properties such as flexibility, mechanical stability, surface porosity and water vapor permeability, and besides being a biocompatible material also presents biological activity to stimulate the angiogenesis, being able to be used in tissue repair. This study demonstrated that ketoprofen was successfully incorporated into natural latex membranes for drug delivery. FTIR indicated that the drug did not interact chemically with the membrane. Moreover, the natural latex membranes released 60% of the ketoprofen incorporated in 50 h. SEM images indicated that a portion of the drug was present on the membrane surface, being this portion responsible for the burst release. The tensile tests showed that the addition of the drug into the natural latex membrane did not influence on the polymer mechanical behavior. In addition, drug-natural latex membranes presented no red blood cell damaging effects. Our data shows that the ketoprofen loaded natural latex membranes is a promising system for sustained drug delivery which can be used to minimize the adverse side effects of high dose systemic drug delivery.
  • The reaction kinetics models of carbon fiber-reinforced plastic (CFRP) degradation in supercritical fluids were established by analyzing the chain scission reaction of a cross-linked network in CFRP. The effect of reaction time and temperature on the residual resin content from the recycled carbon fiber was investigated. The reaction order of CFRP degradation was estimated, and the reaction rate constant was calculated at different reaction temperatures. Reaction kinetics equations of CFRP degradation in different supercritical fluids were also proposed. Results indicated that CFRP degradation was mainly due to the scission of the C–C, C–O, and –O– bonds in the linear chain segment and of the C–N bond in the cross-linked segment of an epoxy resin cure system. The reaction order was 2 or 2.5. The monofilament tensile strength of recycled carbon fiber in supercritical n-butanol and n-propanol, which had higher degradation reaction rates, decreased by about 2% compared with that of the original carbon fiber.
  • The study was planned to utilize chicken feather protein (CFP) and pomelo peel pectin (PPP) to develop the composite film. The five films were prepared with varying proportion of CFP and PPP in ratio of 0:100 (F1), 25:75 (F2), 50:50 (F3), 75:25 (F4) and 100:0 (F5). All films were tested for their mechanical and barrier properties. However, among all the composite films, F2 film was more adequate by considering its overall properties. The WVP, moisture absorption, water solubility, breakage strength and elongation of F2 film were reported as 14.27 × 10⁻⁹ g/Pa h m, 13.83, 100%, 285.885 g and 13.17% respectively and it was ahead of the other films. The selected film F2 was used for wrapping of the fried fish fillet and was stored for 5 days in a closed container and compared with unwrapped fried fish fillet. Wrapping of fried fish fillets resulted in less weight loss, lowered hardness value and reduction in surface microbial count.
  • An organic–inorganic composite of chitosan, nanoclay, and biochar (named as MTCB) was chosen to develop a bionanocomposite to simultaneously immobilize Cu, Pb, and Zn metal ions within the contaminated soil and water environments. The composite material was structurally and chemically characterized with the XRD, TEM, SEM, BET, and FT-IR techniques. XRD and TEM results revealed that a mixed exfoliated/intercalated morphology was formed upon addition of small amounts of nanoclay (5% by weight). Batch adsorption experiments showed that the adsorption capacity of MTCB for Cu²⁺, Pb²⁺, and Zn²⁺ were much higher than that of the pristine biochar sample (121.5, 336, and 134.6 mg g⁻¹ for Cu²⁺, Pb²⁺, and Zn²⁺, respectively). The adsorption isotherm for Cu²⁺ and Zn²⁺ fitted satisfactorily to a Freundlich model while the isotherm of Pb²⁺ was best represented by a Temkin model. That the adsorption capacity increased with increasing temperature is indicative of the endothermic nature of the adsorption process. According to the FTIR analysis, the main mechanism involved in immobilization of metals is binding with –NH2 groups. Results from this study indicated that modification of biochar by chitosan/clay nanocomposite enhances its potential capacity for immobilization of heavy metals, rendering the bionanocomposite into an efficient heavy metal sorbent in mine-impacted acidic waters and soils.
  • In this present study, acid soluble collagen and pepsin soluble collagen from the skin of marine puffer fish Lagocephalus inermis was successfully isolated and characterized. The collagens extracted from the fish skin showed the high yields of both acid solubilized collagen (ASC) (43.1%) and Pepsin soluble collagen (PSC) (56.6%) on the dry weight basis, respectively. Based on electrophoretic patterns, both ASC and PSC consisted of two α- chains (α1 and α2) and were characterized as type I collagen. Amino acid analysis of both the collagen contained the imino acid of 190 and 198 residues/1000 residues, respectively. The ultraviolet absorption spectrum of collagen showed maximum absorption at 230 nm. Fourier transforms infrared spectra of both ASC, PSC was almost similar, and the acidic or enzymatic extraction had no effect on the triple helical structure of collagen. The denaturation temperature (Td) of the collagen was found to be 31.9 °C for ASC and 32.6 °C for PSC, respectively. Both ASC and PSC had highest solubility at acidic pH. Scanning electron microscopy images revealed the porous structure of collagens and both the collagens showed 100% biocompatible on NIH3T3 cell lines. These characteristic features are essential for wound dressing applications. From this study, a useful product recovery was achieved from the underutilized puffer fish, which may serve as an alternative source for mammalian collagen, as well as the management of natural wastes or ecological problems.
  • Solid waste accumulation due to synthetic polymer and polymer composites used in packaging is causing a major threat to human and wildlife. Biodegradation of plastics and biocomposites in environment is a viable solution to this problem and yet a complex phenomenon due to diversity and efficiency of microbial communities involved in attacking the various biocomposite materials. The aim of the present work was to evaluate the biodegradability of biocomposites prepared from potato-peel powder together with polypropylene (POPL/PP) or linear low density polyethylene (POPL/LLDPE) plus maleic anhydride grafted polyolefin compatibilizers. To achieve this, biodegradability tests were conducted according to ASTM D 5338 on the specimen samples for 45 days. The specimens were also analysed post-biodegradation using scanning electron microscope (SEM), thermogravimetric analyser (TGA) and direct scanning calorimeter (DSC) techniques to study the changes in morphology and thermal properties. Biocomposites with 40% (w/w) POPL filler in PP without compatibilizer showed maximum degradation upto 10%, while the LLDPE composites showed biodegradation upto 1%. Addition of compatibilizers reduced the biodegradability in the composites. The results were well corroborated by percentage weight loss in the test biocomposite specimens. Biodegradation in the biocomposites was shown to be dependent on POPL content.
  • A novel grafted copolymer was synthesized from carboxymethyl cellulose (CMC) and carboxymethyl polyvinyl alcohol (CMPVA) using adipic dihydrazide as the crosslinker. The optimized grafted CMC-g-CMPVA with formulation 3% CMC and 1% CMPVA is sensitive to different pH conditions and exhibited a high swelling capacity. The swelling percentages were 360, 1440 and 2277% at pH 1, 7 and 11, respectively and could retain the shape of the hydrogel that assists easy handling. This smart copolymer forms a hydrogel that is pH responsive that could be utilized in the specific pH environment such as in waste water management, agricultural industry, and drug delivery system. The grafted CMC-g-CMPVA was found to be biocompatible with the living cells and has excellent survival rate at lower polymer concentration and, therefore, this grafted copolymer can be employed in biomedical applications such as drug delivery system and scaffolds in the tissue engineering.
  • Ammonium lignosulfonate was modified with carboxylic acids (lactic, oleic) and butyrolactone by physical non-polluting radio frequency cold plasma method. Modified lignosulfonates/polylactic acid (PLA)-based biocomposites with enhanced dielectric and thermal properties have been prepared by melt mixing technique. Some modified lignosulfonates improved processability and rheological properties of PLA. A homogeneous dispersion of lignosulfonates in PLA matrix assures the improvement of hydrophilicity, dielectric, rheological properties and thermal performance of the PLA polymer as they act as nucleating agents increasing crystallinity degree. The dielectric characteristics followed in a large frequency and temperature range. Relaxation transitions and their activation energies were found to be dependent on modified lignosulfonate type incorporated in biocomposites. As PLA is recognized by its biodegradability and the composites containing modified lignosulfonates disintegrate by bio- and environmental degradation even they are incorporated in much resistant matrices as polyolefins, it can supposed that such biocomposites could be considered as medium term degradable ones. Increasing modified lignosulfonates content environmental disintegration period could be shorten.
  • Cobalt(II) doped chitosan bio-composite was prepared, characterized and used to oxoborate separation from aqueous solutions. The adsorption process was carried out in a batch system. The effect of pH, temperature, time and initial boron concentration on the boron adsorption were tested. The maximum boron adsorption was reached at pH range 8.0–8.5 at room temperature and within 60 min. Calculations based on Langmuir and Freundlich models showed the heterogeneous nature of boron adsorption on Co-CTS bio-composite. On the base of research on optimization of pH and results from XRD and FTIR analysis it was found that boron adsorption by Co-CTS occurred through the co-precipitation and adsorption of B on cobalt hydroxide following the Coulomb attraction of B(OH)4⁻ species on positively charged sites and molecular attraction of H3BO3 through hydrogen bond with amine or hydroxyl groups of chitosan. The modelling of the thermodynamic data indicated the nonspontaneous and exothermic nature of the adsorption process. The pseudo-second-order model adequately described the boron adsorption on Co-CTS hydrogel. Desorption by means of alkaline solution at pH 12 was carried out successfully. Adsorption–desorption efficiencies in 3 cycles were almost 100%.
  • Pulp and paper fibers have favorable reinforcement properties, such as constant fiber quality, while being widely available at low cost. However, they also have severe drawbacks related to water uptake and material degradation. In this work, paper was used for sustainable reinforcement in thermoplastic composite laminates, which were characterized by thermal analysis and moisture uptake tests. The porosity of the composite samples with varying paper content and matrix material was determined by thermogravimetric analysis and related to their water uptake. Polypropylene and polyamide 12 matrix composites had the lowest porosities, between 2 and 6 vol%, and thus comparatively low water uptake. Additionally, the influence of moisture uptake on the mechanical properties of the composites was investigated by tensile testing, which resulted in a significant decrease in modulus and strength in the wet state. After drying, however, 70–90% of the original tensile properties were regained. Additionally, a nucleating effect of the paper surface could be observed, which led to a linear increase in matrix crystallinity with increasing paper content.
  • *** In order to see the full paper, please access the link: http://rdcu.be/u6Cl *** In this work, gelatin extracted from chromed leather waste (CLW) was used with cornstarch and glycerol to produce polymeric films. These films were compared with commercial gelatin ones. Gelatin from CLW presented a more pronounced plasticizer behavior than commercial gela-tin. It may have occurred due to its lower molar mass, due to the presence of free amino acids from the partial degrada-tion of the protein polypeptide chain during CLW gelatin extraction, and/or due to the presence of high salts content. The high drying temperature (40 °C) made the drying pro-cess faster than the starch retrogradation process. It resulted in the reduction of films crystallinity and tensile strength, and in the increase of elongation at break. It also increased equilibrium moisture content, as indicated by water sorp-tion isotherms. FTIR spectra indicated that the absorption bands of cornstarch and CLW gelatin films are the same ones found for films of these materials when not combined, which indicates the presence of a system with phase separation.
  • The present study deals with the in situ oxidative polymerization of Pyrrole and 2-Aminopyridine in the presence of titanium dioxide nanoparticles for the first time with the help of H2O2 and FeSO4. Subsequently, the structure and morphology of copolymers, Ppy-AmPy and their nanocomposites, Ppy-AmPy/TiO2 were ascertained using FT-IR, TEM, SEM, XRD, TGA and DTA. These studies have shown that the Ppy-AmPy/TiO2 nanocomposite is thermally more stable, as compared to their copolymers Ppy-AmPy. The copolymers Ppy-AmPy prepared from different monomer ratios and its nanocomposite Ppy-MA/TiO2 have been screened for their possible in vitro antibacterial activity against gram positive and gram negative strains using Gentamicin as standard drugs and their toxicity was assayed on Normal RBCs. A molecular docking simulation was used to predict the modes of interactions of the drugs (Ppy-AmPy and Ppy-AmPy/TiO2) with the haemoglobin. The molecular docking results indicated that the modes of interactions between the two (Ppy-AmPy and Ppy-AmPy/TiO2) and Hb can be considered as groove binding.
  • A new chitosan derivative, N-guanidinium chitosan acetate, has been synthesized by direct guanylation of chitosan by cyanamide in presence of scandium(III) triflate under mild acidic condition. Starting from this material, N-guanidinium chitosan/silica microhybrids were prepared via a sol gel method using 3-glycidoxypropyl trimethoxysilane as silica precursor. Both N-guanidinium chitosan and the N-guanidinium chitosan/silica hybrid were characterized by a range of analytical techniques such as ²⁹Si/¹³C solid state NMR, FT-IR, scanning electron microscopy, thermogravimetry and elemental analysis. The characterization of the chitosan/silica hybrid indicated that this material is a highly hydrophilic nanocomposite material containing an organic core and a highly condensed silica shell. The N-guanidinium chitosan/silica microhybrids display excellent adsorption properties for anionic dyes such as methyl orange (MO) with very high capacities up to 917 mg/g. The fixation of MO as anionic dye was investigated in detail as a function of contact time, pH and the MO concentration. The adsorption kinetics of MO on N-guanidinium chitosan/silica microhybrids was more accurately described by pseudo second-order model. Langmuir isotherm model exhibited a better fit with adsorption data than Freundlich isotherm model. This work opens new possibilities for using N-guanidinium chitosan as a reusable adsorbent for water purification.
  • In this study, surface modification is used to improve the compatibility of Kenaf fibers (KFs) and multi-walled carbon nanotubes (MWCNTs) in a polylactic acid (PLA) matrix, as well as to enhance the mechanical properties. Through the use of a silane coupling agent, the KF is grafted with functional groups to generate a chemical bond with the PLA; the modified KF shows high compatibility in the PLA matrix. Compared to the bare PLA, the optimal KF/MWCNT/PLA composite (PC1F30-OX) shows increases of 58% in tensile strength, and 113% in impact strength. A small addition of MWCNTs (1 wt%) dramatically improves the antistatic ability by lowering the surface resistance to 3.47 GΩ. With the addition of hydrophilic KF into the PLA, the composite becomes much more environmentally friendly, and the biodegradation rate can be controlled by the amount of KF added. The addition of hydrophilic KF allowed the composite to accommodate more enzyme to hasten the biodegradation; almost complete decomposition occurred after 11 weeks.
  • A novel herbicide bead was developed by phase separation, utilizing modified cassava starch (CSt), sodium alginate (SA) and 2,4-dichlorophenoxy acetate (2,4 DA), and the beads were also coated with natural rubber grafted with cassava starch (NR-graft-CSt) to aid their water resistance. The alginate gel beads with 65% entrapped 2,4 DA showed 90% release within 24 h. The incorporation of CSt in the beads markedly improved their encapsulation efficiency to 98% and sustained the release of the herbicide for 700 h. The water resistance was improved by coating the beads with NR-graft-CSt when compared with the pure CSt/SA bead. The synthesized bead has excellent potential for agricultural applications.
  • Glycolipids, consisting of a carbohydrate moiety linked to fatty acids, are microbial surface active compounds produced by various microorganisms. Glycolipids are characterized by highly structural diversity and have the ability to decrease the surface and interfacial tension at the surface and interface respectively. It presented initially a detailed classification of glycolipid including rhamnolipids, trehalolipids, mannosylerythritol-lipids, cellobiolipids; along with their producing strain. The review described the main functional properties of glycolipid including emulsification/de-emulsification capacity, foaming and moisturizing, viscosity reduction and hydrocarbon solubilizing and mobilizing capacities. Owing these properties, they can be applied in environmental fields as hydrocarbon emulsifiers, solubilizing and mobilizing agents, for their moisturizing capabilities and ability to reduce viscosity. The review will present a detailed classification of glycolipid biosurfactants, functional properties and the potential related applications in environment and bioremediation.
  • Magnetic chitosan grafted with Schiff’s base polymer (M-Schiff’s-Chit) was prepared as a green sorbent starting from shrimp peels for the effective removal of hexavalent chromium. Chitosan extraction involved three main stages as preconditioning, demineralization deproteinization and deacetylation. The grafting process is confirmed by elemental analysis, Fourier transform infrared spectroscopy. Adsorption experiments were carried out in batch sorption mode to investigate the effect of pH, contact time, sorbent dose, concentration of Cr(VI) and evaluating the thermodynamics. Sorption kinetics are effectively modeled using the pseudo-second order rate equation while Langmuir equation successfully fits sorption isotherms. The sorption is endothermic, spontaneous and entropic. Chromate desorption can be successfully performed with 2 M of NaCl in 0.5 M NaOH and the sorbent can be recycled for at least three sorption/desorption cycles without significant loss in sorption/desorption performances. Furthermore, the environmentally friendly and low-cost M-Schiff’s-Chit could be applied as an effective sorbent to remediate Cr(VI) contamination from tannery effluent.
  • Three-dimensional polypyrrole/chitosan nanocomposite monoliths are fabricated by polymerization of pyrrole in chitosan aqueous solution. The static polymerization of pyrrole monomer and the cross-linking of chitosan by glutaraldehyde occur simultaneously, resulting in the self-assembly of polypyrrole/chitosan nanocomposite aerogel monolith. The addition of methyl orange and glutaraldehyde and the static reaction play key roles in the formation of the self-standing aerogel monolith. The as-prepared monolith with larger specific surface area exhibits much better adsorption capability for Cr(VI) removal in comparison with that prepared without the addition of glutaraldehyde. The adsorption process and adsorption isotherms are found to well follow the pseudo-second-order and Langmuir models, respectively. Furthermore, this polypyrrole/chitosan nanocomposite monolith is stable and recyclable. About 73.5% of the initial adsorption capability is kept after eight adsorption–desorption cycles. The polypyrrole/chitosan nanocomposite monolith can be a promising candidate for the efficient removal of Cr(VI).
  • Five new polyesters fully based on renewable organic compounds were synthesized by melt polycondensation of a new bisfuranic monomer prepared from methyl 2-furoate and levulinic acid with bio-based aliphatic dihydroxy compounds. The polymerization process consisted of a precondensation step under a stream of dry argon at atmospheric pressure involving elimination of methanol, followed with a melt polycondensation step at 180 °C under vacuum. The polyesters were characterized by infrared spectroscopy (FTIR) and elemental analysis. The thermal behavior of the polyesters was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis. All polyesters synthesized showed good thermal stabilities, they experience only 1% mass loss at temperatures higher than 270 °C. The glass transition temperatures (Tg) of the polyesters, measured by DSC, were in the range from 37 to 119 °C. The swelling capacity was measured by beaker test method; the capacity range observed was from 112 to 232%. Based on this percentage range the polyesters are generally considered hydrophilic.
  • Gelatin microsphere, as a sustained release urea carrier, was prepared by an emulsion–cross linking method with glutaraldehyde (GA) as a cross-linking agent. The influence of urea/gelatin ratio, emulsifier, GA concentration, and cross-linking time on the urea loading and encapsulation efficiency was investigated using response surface methodology. It was found that the urea/gelatin ratio had greater impact on urea loading and encapsulation efficiency than other factors. Equilibrium swelling of microspheres were performed in distilled water, and as expected, the water uptake decreased with the increase of GA as well as the reaction time. The cumulative release of urea from the microspheres decreased with the increase of reaction time and urea release presented a Fickian trend, indicating a diffusion controlled urea release mechanism. The insight from this study is useful to the design and process of controlled release urea fertilizers.
  • Today, environment pollution control is a matter of concern, everybody is willing to make a product that should be ecofriendly. Nowadays, water resources are full of untreated waste materials, discharge of hazardous and toxic dyes coming from textile and other chemical industries. These environmental hazards are difficult to remove by commercial water treatment plans, thus we need something that would present an efficient means for removal of these hazards. In this research paper, we have synthesize silver nanoparticle in a green way by using aqueous extract of Allium cepa (onion), and further these silver nanoparticle were tested for the catalytic degradation of various dyes by UV/Visible spectroscopy and silver nanoparticle showed reduction in dyes intensity after a particular period of incubation time. SEM and TEM, Particle size and Zeta potential analysis was done to analyze the surface morphology, particle size range and stability of the silver nanoparticle. Greenly synthesized silver nanoparticle was found to be spherical in shape, having particle size value ranged from 50 to 100 nm with a zeta potential value of −29 mV. An EDX spectroscopy method was used to confirm the presence of silver nanoparticle in the synthesized material. An X-ray crystallography was done to ensure the crystallinity of the silver nanoparticle. Further an ATR-FTIR was performed to confirm the capping of the silver nanoparticle with the phenolic group of the onion. All these study emphasized that silver nanoparticle capped with onion (AgNPs@Ac) is the excellent catalyst for the reduction of hazardous and toxic dyes as well as they serve best purpose of the eco-friendly approach.
  • A modified sequential mass-suspension polymerization was employed to ensure adequate dispersion of lignin into the monomeric phase. Due to its complex macromolecular structure and low compatibility with styrene, eucalyptus wood-extracted lignin, via a modified Kraft method, was esterified with methacrylic anhydride to ensure organic phase homogeneity into the reaction medium. Infrared spectroscopy showed a decrease in the hydroxyl band, a characteristic of natural lignin (3200–3400 cm⁻¹) and an increase in the characteristic ester band (1720–1740 cm⁻¹) whereas nuclear magnetic resonance measurements exhibited intense peaks in the range from 1.7 to 2.05 ppm (–CH3) and 5.4 to 6.2 ppm (=CH2), related to methacrylic anhydride. Comparatively, the esterified lignin also displayed an increase of its glass transition temperature for 98 °C, related to natural lignin, whose Tg was determined to be equal to 91 °C. Styrene/lignin-based polymers exhibited higher average molar masses in comparison to the values observed for polystyrene synthesized with similar amounts of benzoyl peroxide, due to the ability of lignin to act as a free-radical scavenger. Composites obtained with styrene and natural or esterified lignin were successfully synthesized, presenting regular morphology and proper lignin dispersion. Based on a very simple polymerization system, it is possible to enhance the final properties of polystyrene through the incorporation of lignin, which represents an important platform for developing attractive polymeric materials from renewable resources.
  • Wheat gluten based bioplastics with shrimp shell waste filler were prepared using compression molding. The effects of various amounts (0, 2.5, 5.0, 7.5 and 10 wt%) of shrimp shell powder and calcined shrimp shell powder on the tensile, morphological, thermal properties, and degradation of wheat gluten composites were investigated. The addition of shrimp shell powder improved the tensile properties of the wheat gluten composites. The tensile strength of the wheat gluten composite with 2.5 wt% of shrimp shell powder increased twofold compared to the wheat gluten based-bioplastic without shrimp shell loading. A comparison of the performance of the wheat gluten composites made with different shrimp shell types revealed that composites with calcined shrimp shell powder had better tensile, morphological and thermal properties due to the altered layer structure and higher mineral content resulting from calcination. Moreover, calcined shrimp shell powder had a significant influence on the degradation process of the wheat gluten composite.
  • The blends of poly(l-lactide) (PLLA) and poly(butylene succinate) (PBS) were prepared by melt mixing in a Brabender mixer, and the structures and properties of the binary blends were characterized. It was found that the tensile properties were higher than the anticipated values on the basis of the mixing rule. Notably, a synergistic effect was discovered at 80 wt% PBS where the blend was toughened and strengthened simultaneously. It is believed that the distinctive tensile properties were achieved by the effect of rigid PLLA fillers, and blending brittle PLLA in the ductile PBS matrix gave the composite material enhanced toughness and strength. Scanning micrographs and differential scanning calorimetry measurements showed consistent results.
  • A novel thin-film composite (TFC) nanofiltration membrane was prepared by interfacial polymerization of polyamide layer on a polyethersulfone support, using monoethanolamine (MEA) and diethanolamine (DEA) with m-phenylenediamine as monomers and trimesoyl chloride (TMC) as crosslink agent. The membrane surface before and after using aminoalcohol monomers (MEA and DEA) was investigated in detail using ATR-FTIR, TGA, AFM and SEM. The AFM and SEM images showed that addition of MEA and DEA had a strong impact on surface morphology. The polyamide layer thickness of control and modified TFC membranes based on MEA and DEA were calculated to be in 180–230 nm range and the mean pore sizes were about 0.35–1.2 nm. The RO performance tests indicated that addition of MEA and DEA can increase the NaCl and Na2SO4 rejection remarkably with little decline in the pure water permeation flux.
  • Biodegradable composites of polysaccharides (cellulose, starch, and ethylcellulose) with low-density polyethylene (LDPE) and poly(ethylene oxide) (PEO) as well as composites of two polysaccharides (cellulose–chitin, cellulose–chitosan, starch–chitin, starch–chitosan) with LDPE were produced in a rotor disperser under conditions of shear deformation. Using various physicochemical (mechanical tests, FTIR-spectroscopy) and structural (SEM) methods, the properties and structure of obtained composites were studied. The investigation of the change in the fractional composition depending on the nature of third component has shown that the introduction of PEO leads to appearance of fraction with coarse particles, while the addition of second polysaccharides results in production of finely-dispersed powders. The comparison of the mechanical properties of binary and ternary composites has showed that the presence of third component leads to change in their characteristics. The investigation of sample biodegradability by three independent methods showed that the introduction of third component leads to a significant increase in the biodegradation as compared to the binary polysaccharide–LDPE composites studied earlier.
  • In this work, rigid polyisocyanurate foams were prepared at partial substitution (0–70 wt%) of commercially available petrochemical polyol, with previously synthesized biopolyol based on crude glycerol and castor oil. Influence of the biopolyol content on morphology, chemical structure, static and dynamic mechanical properties, thermal insulation properties, thermal stability and flammability was investigated. Incorporation of 35 wt% of crude glycerol-based polyol had reduced average cell size by more than 30% and slightly increased closed cell content, simultaneously reducing thermal conductivity coefficient of foam by 12% and inhibiting their thermal aging. Applied modifications showed also positive impact on the mechanical performance of rigid foams. Increase of crosslink density resulted in enhancement of compressive strength by more than 100%. Incorporation of prepared biopolyol resulted in enhancement of thermal stability and changes in degradation pathway. Up to 35 wt% share of crude glycerol-based polyol, foams showed similar flammability as reference sample, which can be considered very beneficial from the environmental point of view.
  • The aim of the study was to characterization of polyhydroxybutyrate (PHB) produced by novel bacterium Lysinibacillus sphaericus BBKGBS6 isolated from soil. The present study reports that the strain L. sphaericus BBKGBS6, which was isolated from agricultural soil and is capable of producing PHB. Extraction of PHB was done by solvent extraction method. The results indicated the presence of crotonic acid and confirmed the presence of polyhydroxybutyrate in the sample. The FTIR spectra were observed characteristic absorption bonds for ester and the presence of C=O and C–O were obtained. GCMS results showed the major molecular fragmentation were, 117 m/z (C5H9O3⁺), 104 m/z (C4H7O3⁺), 74 m/z (C3H6O2⁺), 61 m/z (C2H3O2⁺), 43 m/z (C2H3O), 59 m/z (C2H3O). ¹H and ¹³C NMR spectra were recorded using purified samples. The molecular weight of PHB (5.64 × 10⁵⁾ was estimated based on viscosity measurement. Films were prepared by the solvent casting method. The structure of crystalline polymers can be determined or refined through best fitting of X-ray powder diffraction profiles. The procedures provide results grossly in agreement with respect to the confirmation of the chain in the powder but differing significantly on a more detailed scale. Such differences represent an additional reason of interest in performing a new structural study. Differential scanning calorimetric experiments was performed using Universal V4.5A TA Instruments, (m.p. 156.61 °C; ΔH = 28.54 J/g) USIC Dharwad. The crystallinity (Xc) of PHB is calculated as per equation given below \({{X}_{c}}\,=\,{D}{{H}_{f}} \times {1}00/{D}{{H}_0} \times {W}\). The PHB extracted, PHB Sigma and PHB–TS showed two endothermal peaks in between 140 and 200 °C. The enthalpy of melting (ΔHf) was 28.09 J/g for standard PHB and for extracted one is 56.42 J/g. The glass transition temperature of the sample was 140 °C and amorphous temperature was 176.08 °C. Thermo gravimetric analysis (TGA) is a method of thermal analysis in which changes in physical and chemical properties of materials are measured as a function of increasing temperature (with constant heating rate), or as a function of time (with constant temperature and/or constant mass loss). The decomposition temperature at a 10% level determined by TGA for pure PHB in ScCO2 at 70 °C and 22 MPa was 293.32 °C. Tensile strength of PHB film (28.23 Mpa) was carried out according to ASTMD 882 using universal testing machine (Model Lx 5, LYOD ISNT). Water vapor transmission rate of PHB film (29 g/m²/day) was measured as per ASTM E96-95 and carried out according to the desiccant method. Oxygen transmission rate of PHB film 472.36 (cc/m²/day/atm 65% Rh and 27 °C) was measured as per the method of ASTM D-1434-66.
  • The aim of this work was the production and characterization of films prepared from starch, gelatin and methyl esters of epoxidized macauba (Acrocomia aculeata), corn (Zea mays), pacu (Piaractus mesopotamicus), pintado (Pseudoplatystoma corruscans) and soybean (Glycine max) and also multilayer films of polyhydroxyalkanoates (PHA) conjugated with two of the epoxides that presented the best results in characterizations. The two types of films EEF (Epoxidized esters films) and EEFPHA (Epoxidized esters and PHA conjugated films) were both characterized for their visual aspects, solubility in water and acid, width, color, opacity, water vapor permeability, tensile strength and elongation. EEFPHA were also characterized by differential scanning calorimetry, scanning electron microscopy and X-ray diffraction analyses. The epoxidation reaction was successfully carried out; with the GC-MS analysis indicating the formation of epoxidized esters derived from linoleic and oleic acids. The addition of the epoxidized esters to the EEF films caused an increase in film thickness, opacity, solubility in water, tensile strength and elongation, while the solubility in acid presented the same value as compared to the blank sample. In the EEFPHA samples, addition of filmogenic solution of epoxidized esters from corn and macauba presented a value exceeding the standard in the thickness, opacity, water solubility, water vapor permeability and tensile strength analyses. In the analysis of solubility in acid these samples showed results below the standard, and the elongation test showed values very close. DSC, SEM and XRD results showed that there was a polymeric incorporation between the starch and the PHA.
  • In this work, the effect of the high molecular weight bio-based diamine on the chemical structure and selected properties of poly(ether-urethane-urea)s has been investigated. The ether-urethane prepolymer was cured using 1,4-butanediol and/or bio-based diamine. Mentioned chain extenders were used separately or in the mixture, and their different molecular weight and chemical structure resulted in obtaining materials with diversified mechanical performence. The presence of specific chemical groups (i.e. urethane and urea groups) was confirmed by FTIR method. For the synthesized poly(ether-urethane-urea)s morphology and fracture mechanism, thermo-mechanical properties and mechanical properties were determined and discussed. Results confirmed that bio-based diamine acts as soft segments, and this is connected with changing of mechanical and thermo-mechanical properties of prepared partially bio-based poly(ether-urethane-urea)s. The increasing content of bio-based diamine resulted in increasing of tensile modulus and decreasing of tensile strength and elongation at break, and this is resulted from chemical structure of bio-based diamine (i.e. presence of aliphatic side chains).
  • Hemicellulose-based composites have become promising candidates for eco-friendly packaging applications because of their biodegradability and cost-effectiveness. However, the inherently poor mechanical properties of hemicellulose-based composites largely hinder their potential for targeted application. Fortunately, nanocrystalline cellulose (NCC), an eye-catching nanomaterial, may offer opportunities for addressing the above issue due to its outstanding mechanical properties and environmental friendliness. Herein, a comparative study was conducted on the effect of unmodified and cationically modified nanocrystalline cellulose (CNCC) on the overall properties of the as-prepared hemicelluloses (HC)/sorbitol (SB) films. Scanning electron microscopy (SEM) image shows that the addition of CNCC imparted a relatively smooth surface to the obtained HC/SB films in comparison to NCC. Furthermore, CNCC reinforced HC/SB films exhibited improved thermal stability as compared to that with NCC. From rheological behavior evaluation, the presence of NCC, particularly CNCC, had an important effect on thickening HC/SB suspensions. The tensile stress of the composite films with 9% NCC and 9% CNCC was 9.18 and 10.44 MPa, respectively, which was increased by 14 and 30% in comparison to that of pure HC/SB film (8.05 MPa). The marked increase in elastic modulus as a function of the added NCC or CNCC was also identified. This result strongly supports the conclusion that the addition of NCC or CNCC was effective in improving the mechanical properties of HC/SB films.
  • In this research, corn stalk fibers (CSF) grafted polyacrylic acid (PAA) on their surfaces (CSF-g-PAA) were successfully prepared via heterogeneous esterification in the case of maintaining inherent fiber framework and shape. It can be used to removal cationic contaminants from aqueous solution. Four dyes and three metal ions were employed as models of cationic adsorbates to survey its adsorption performance. All of them showed high adsorption capacities, even the lowest RhB reached 179 mg/g. The CSF-g-PAA not only has a high adsorption capacity but also maintains inherent fiber framework, showing features of easy separation. The adsorption capacity reached 370 mg/g for methylene blue (MB), which was significantly far higher than that of original CSF (<30 mg/g). MB adsorption followed pseudo-second-order kinetic and the Langmuir isotherm model. The adsorbent can be separated easily and rapidly from wastewater through a sieve of 200 mesh. Adsorption and desorption were also evaluated. The CSF-g-PAA might be used as a promising adsorbent for practical application because of its low cost and high performance.
  • A composite material containing polyacryl amide (PAA) and lignin (L) was developed and characterized for effective Bisphenol A (BPA) removal. Fundamentals of the proposed approach is based on adsorption of BPA molecules on PAA-L composite. Characterization of material was carried out by FTIR and PZC analysis. Adsorption of BPA ions from aqueous solution as a function of BPA concentration, pH, ionic strength, temperature, and reusability of adsorbent was investigated in detail. The adsorption data were analyzed by using the Langmuir, Freundlich and Dubinin–Radushkevich (DR) models. As a result of this analysis, r² values were found as 0.991, 0.984, and 0.873, respectively. Maximum adsorption capacity obtained from Langmuir model was calculated as 55.358 mg g⁻¹. Freundlich heterogeneity was found as 0.637 while EDR value obtained from DR model as 12.219. Experimental results showed that the adsorption of BPA is based on chemical binding, exothermic and spontaneous process. Reusability of PAA-L adsorbent was verified by recovery experiments for a lot of times and was not observed any change or deterioration on the material.
  • Chemical modification of potato starch with citronellyl methacrylate monomer, characterization of obtained materials and its physicochemical properties have been presented. The chemical modification of potato starch under the grafting process with citronellyl methacrylate led to the preparation of novel, amphiphilic materials where from 0.3 to ca. 1.6 hydroxyl groups per glycoside unit were replaced by poly(citronellyl methacrylate) chains. The grafting of poly(citronellyl methacrylate) chains onto starch backbone caused considerably changes in the morphology, polarity, solubility, chemical stability, moisture absorbance, gelatinization properties, thermal stability and decomposition mechanism of the prepared copolymers as compared to native potato starch. The influence of the grafting percent on the above mentioned properties as well as on the pyrolysis mechanism was discussed in detail.
  • Herein, a functional S-valine amino-acid (valine) based poly(amide–imide) (PAI) was prepared in a green situation. Carbon nanotubes (NTs) were functionalized with valine to fabricate NT/PAI nanostructures composite (PNCs) by incorporating NTs into the PAI matrix. Homogeneous dispersion of NTs was achieved by the modified NTs and ultrasonication method. The influences of the functionalized NTs on the morphology, structure, and thermal of PNCs were characterized extensively by several techniques. The findings showed that the modified NTs caused a fine interaction with PAI chains and improvement dispersion of NTs in the matrix along with much enhanced thermal stability.
  • The present work proposes the recycling of expanded polystyrene (EPS) waste, in order to contribute to reduce the excessive accumulation of this material in sanitary landfills in Mexico. The recovery process of EPS is proposed using a biosolvent (Lemon limonene-LL) to prepare a polymeric solution (EPS-LL), and its subsequent evaluation as a coating on a lignocellulosic Kraft paper of 200 g/m² and a Gurley porosity of 15–30 seg/100 ml. The effect of different resin concentrations and resin coating layers on the compressive and tensile strength was tested, as well as the resistance of the treated paper to water absorption. Results indicated that the coating layers gradually increased the mechanical strength of the Kraft paper, both tensile and compressive, but only up to a certain grammage of resin applied. Regarding to water absorptiveness, the treated paper showed a significant reduction of water absorption, from 230 g/m² with one resin layer to 23 g/m² with three resin layers. The results demonstrate the potential of recycling EPS to obtain a composite material with good hydrophobic characteristics and mechanical strength. This study also intends to provide an added value of this recycled polymer, rather than continuing the current custom of discarding it in sanitary landfills.
  • Starch was extracted from Sorghum bicolor grains by alkali steeping method and was utilized for the production of absorbent material by grafting and crosslinking with binary mixtures of vinyl monomers viz. acrylic acid and acrylamide. Both unmodified and modified starches were characterized with Thermogravimetric analysis, Infra-Red spectroscopy, Scanning electron microscopy and X-ray diffraction analysis, to ascertain the modification of the starch. The parameters of the reaction system viz. initiator concentration, monomer concentration, starch to monomer ratio, etc. were optimized. The modified starch showed enhanced water absorption in the range of 49–85 g/g. Absorbency of the products increased after treatment with aqueous alkali solution due to saponification at higher temperature. The saponified products showed increased water absorption level in the range of 245–400 g/g. The product thus obtained using optimized condition of grafting, on saponification found to be highly superabsorbent displaying the water absorbency of 400 g/g. The influence of pH on absorption of water was also tested and best results were obtained at pH 7–8.
  • In the present work, adiabatic copolymerization allowed us to synthesize two poly(AM-4VP) (s) copolymers with various macromolecular weights as determined by viscosity measurement. The ¹H-NMR was used for copolymer’s structure verification. UV–Visible was also used to determine the percentages of acrylamide (AM) and 4-vinylpyridine (4VP) monomers in each copolymer. Synthesized copolymers were tested in the aim to eliminate turbidity from bentonite suspension. A first study was realized on a conventional jar-test in order to determine the optimum parameters, such as time and the speed of stirring of different flocculants, during the flocculation process. Optimized parameters were then used on a semi-industrial pilot of coagulation/flocculation. Flocculation efficiency of the synthesized copolymers was compared with a commercial cationic flocculant FO4910 obtained from Sigma-Aldrich (France). The effect of macromolecular weight and 4VP amounts were also studied. The flocculation experiments results showed that a good turbidity removal superior to 80% was recorded using low copolymers concentrations of <5 mg/L.
  • In this study, a novel adsorbent was developed by loading polypyrrole (PPy) onto biochar (BC) prepared by slow pyrolysis of pomelo peel. This PPy-grafted BC mainly exhibited anion-exchange behavior, which dramatically increased fluoride adsorption capacity. The effects of various factors (adsorbent dosage, pyrrole concentration, initial solution pH, co-existing anions and temperature) on the fluoride adsorption were investigated. The adsorbent was characterized by scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and automatic titration methods. Results showed that the optimized adsorbent (BP-0.1) performed excellently at pH 2.8–10.0, and possessed positive charge at pH < 8.6. The adsorption isotherm data were fitted well by the Langmuir model and the maximum adsorption capacity was 18.52 mg/g at 25 ± 2 °C. The adsorption kinetics followed the pseudo-second-order model and adsorption equilibrium was achieved at 24 h. Although both HCO3⁻ and CO3²⁻ had great influence on F⁻ adsorption, there was no significant impact in the presence of Cl⁻, NO3⁻ and SO4²⁻. Real groundwater study showed that 2.5 g/L of BP-0.1 could effectively reduce F⁻ from 10.0 to 1.4 mg/L at pH 5.0. Thermodynamic parameters confirmed the spontaneous and endothermic nature of the adsorption process. Effect of pH, XPS analysis and the change of amount between Cl⁻ and F⁻ in the adsorption process revealed that ion exchange and electrostatic attraction were involved in the adsorption process and ion exchange was the main adsorption mechanism.
  • The effect of microstructure of high density polyethylene (HDPE) on catalytic degradation over fluid catalytic cracking (FCC) catalyst and Nano clay is investigated. An ethylene/1-hexene copolymer (HDPE) was fractionated based on 1-hexene content to different fractions using preparative temperature rising elution fractionation (P-TREF) method. The short chain branch (SCB) content of each fraction calculated based on ¹H NMR results. The homogenous SCB content fractions were subsequently analyzed using TGA and thermal degradation behavior of samples were compared with catalytic degradation. The results showed that FCC, in contrast to nano clay, is more sensitive to microstructure of HDPE during catalytic degradation. Therefore, linear chains can start degradation sooner on FCC than the branched chains. In comparison of nano clay and FCC it was found that the nano clay, reduces temperature at maximum degradation rate (Tmax), but FCC reduces the T5% and Tmax significantly.
  • A modified sequential mass-suspension polymerization was employed to ensure adequate dispersion of lignin into the monomeric phase. Due to its complex macromolecular structure and low compatibility with styrene, eucalyptus wood-extracted lignin, via a modified Kraft method, was esterified with methacrylic anhydride to ensure organic phase homogeneity into the reaction medium. Infrared spectroscopy showed a decrease in the hydroxyl band, a characteristic of natural lignin (3200–3400 cm⁻¹) and an increase in the characteristic ester band (1720–1740 cm⁻¹) whereas nuclear magnetic resonance measurements exhibited intense peaks in the range from 1.7 to 2.05 ppm (–CH3) and 5.4 to 6.2 ppm (=CH2), related to methacrylic anhydride. Comparatively, the esterified lignin also displayed an increase of its glass transition temperature for 98 °C, related to natural lignin, whose Tg was determined to be equal to 91 °C. Styrene/lignin-based polymers exhibited higher average molar masses in comparison to the values observed for polystyrene synthesized with similar amounts of benzoyl peroxide, due to the ability of lignin to act as a free-radical scavenger. Composites obtained with styrene and natural or esterified lignin were successfully synthesized, presenting regular morphology and proper lignin dispersion. Based on a very simple polymerization system, it is possible to enhance the final properties of polystyrene through the incorporation of lignin, which represents an important platform for developing attractive polymeric materials from renewable resources.

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