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3D Printing with Bacterial Cellulose-Based Bioactive Composites for Design Applications
... These bacteria utilize various carbon sources, most commonly glucose, and convert them into long, interwoven chains of highly pure crystalline cellulose fibers without lignin and hemicellulose, which are typically present in plant cellulose (Vasconcelos et al. [11]). The resulting BC-based biofilms exhibit impressive tensile strengths exceeding 300 MPa, rivaling some engineered plastics (Turhan [23]). Additionally, their intricate network of ultrafine nanofibers creates a highly porous structure with unmatched water absorption capabilities, reaching upwards of 98% by weight (Derme et al. [12]). ...
... While chemical crosslinking, often using aldehydes, offers excellent results, its cytotoxicity raises concerns (Jimtaisong & Saewan [13]). As a result, the focus has shifted towards natural gelling agents and natural cross-linkers and which are becoming increasingly explored for biocomposites (Ma et al. [14]; Turhan [23]). The synergistic interactions and conformational changes arising from the different polymer structures contribute to this improved performance (Altaner et al. [15]; Simoes et al. [16]). ...
... The synergistic interactions and conformational changes arising from the different polymer structures contribute to this improved performance (Altaner et al. [15]; Simoes et al. [16]). One of the strong candidates is pectin (Turhan [23]) a major component of plant cell walls, particularly in citrus fruits. It constitutes nearly two-thirds of the dry weight of these walls, providing structural integrity, strength, and flexibility. ...
Adaptive façades predominantly employ rigid body mechanics to initiate motion. The manufacture of such systems is costly, susceptible to malfunction, and challenging to maintain, rendering them both economically and environmentally unviable for operational purposes. However, compliant mechanisms are mechanical systems that achieve motion or force transmission through the deformation of flexible materials, rather than traditional rigid joints or linkages. For the development of compliant systems in architectural applications, material technology has been critical, as these systems cannot be considered without materialization due to the need for an elastic capability for the curved crease. State-of-the-art biobased materials can be utilized for compliant mechanisms in the form of lightweight biofilms. These materials are derived from renewable biological resources such as plants and microorganisms, representing a sustainable alternative to traditional, fossil fuel-based materials and reducing dependence on non-renewable resources. This paper explores the use of bacterial cellulose (BC) biofilms for compliant systems to design a biodegradable, lightweight adaptive façade system. The methodology is divided into three steps: production of biofilm, daylight permeability analysis and digital fabrication, and production of BC-based compliant mechanisms. The results have shown that bacterial cellulose-based biofilms have a great potential for the materialization of CLF as a biodegradable and lightweight alternative for developing into an adaptive facade system through the passive actuation method in different environmental conditions.
... In the literature on biobased design and computation, the potentials of this kind of approach are discussed widely, to create innovative materials and structures. By the integration of the digital fabrication technologies, additive and subtractive approaches and methods such as laser cutting and 3D printing it is possible to accelerate research and practice in the bio-design field (Turhan et al., 2022). ...
... Although the use of bacterial cellulose for design and fabrication is still in its infancy, early experiments laying the ground for this current research have explored the bending behavior of BC composite through a dynamic relaxation simulation and a 3D-printed scaffold for an analog and digital comparison; 29 the pure BC biofilm and BC-jute composite samples through introducing specific material properties into a digital medium, deducted from tensile tests; 34 and the potentials of 3D printing with BC and BC-jute composite as a biodegradable product. 35 There are various valuable arguments on why A. xylinus bacteria could be used as a bio-based material for customized design applications. It is known, for example, that it could remain active and be attached to a 3D network created by cellulose fibers. ...
Recent studies in digital design and fabrication processes focus on the potentials of using biological systems in nature as mathematical models or more recently as bio-based materials and composites in various applications. The reciprocal integration between mechanical and digital media for designing and manufacturing bio-based products is still open to development. The current digital form-finding scripts involve an extensive material list, although bio-based materials have not been fully integrated yet. This paper explores a customized form-finding process by suggesting a framework through mechanically informed material-based computation. Bacterial cellulose, an unconventional yet potential material for design, was explored across its biological growth, tensile properties, and the integration of datasets into digital form finding. The initial results of the comparison between digital form finding with conventional materials versus mechanically informed digital form finding revealed a huge difference in terms of both the resulting optimum geometry and the maximum axial forces that the geometry could actually handle. Although this integration is relatively novel in the literature, the proposed methodology has proven effective for enhancing the structural optimization process within digital design and fabrication and for bringing us closer to real-life applications. This approach allows conventional and limited material lists in various digital form finding and structural optimization scripts to cover novel materials once the quantitative mechanical properties are obtained. This method has the potential to develop into a commercial algorithm for a large number of bio-based and customized prototypes within the context of digital form finding of complex geometries.
This book series aims to become the leading annual book series in fields related to Civil, Structural, and Transportation Engineering. The goal is to gather scholars from all over the world to present advances in the relevant fields and to foster an environment conducive to exchanging ideas and information.
Geometric-driven form generation was the product of the institutionalised division between form, structure, and material that was firmly ingrained in modernist design theory and paralleled by a systematic segmentation between modelling, analysis, and manufacture. This preference for form above substance was included into the creation and design logic of CAD. As a result of current pressures and an increasing understanding of the shortcomings and environmental risks of this strategy, modern design culture is transitioning to a more material-aware mind-set. Inspired by natural processes, where form development is dependent on local variations in the material properties to maximise performance while using the fewest resources possible. This approach assumes that material comes first and that shape results from the organisation of material qualities in relation to structural and environmental performance. Products that are not based on fuel have outstanding mechanical and biodegradability properties, particularly bio-polymers. Bacterial cellulose has proven to be an extraordinarily versatile bio-polymer, drawing interest in a wide range of practical scientific applications including electronics, biomedical devices, and tissue-engineering. Development of bio-fabrication methods connected to material-informed computational modelling and material science is required by the introduction of bacterial cellulose as a building material. The paper reviews, suggests and demonstrates approaches for a material-based strategy in exploiting the enormous potential of Bacterial Celulose-based bio-materials and their potential to have a profound impact on the ideas of architectural innovation and sustainability for a better future.
Three-dimensional (3D) printing manufactures intricate computer aided designs without time and resource spent for mold creation. The rapid growth of this industry has led to its extensive use in the automotive, biomedical, and electrical industries. In this work, biobased poly(trimethylene terephthalate) (PTT) blends were combined with pyrolyzed biomass to create sustainable and novel printing materials. The Miscanthus biocarbon (BC), generated from pyrolysis at 650 °C, was combined with an optimized PTT blend at 5 and 10 wt % to generate filaments for extrusion 3D printing. Samples were printed and analyzed according to their thermal, mechanical, and morphological properties. Although there were no significant differences seen in the mechanical properties between the two BC composites, the optimal quantity of BC was 5 wt % based upon dimensional stability, ease of printing, and surface finish. These printable materials show great promise for implementation into customizable, non-structural components in the electrical and automotive industries.
Understanding the basic properties of natural fibers is important to determine the optimal intended uses for instance as high-quality bio-composite raw material. This review describes the characteristics, and potential uses of some natural fibers in order to improve their sustainability and economic values. The natural fibers have low density and high strength to weight ratio and reduction make them potential as light weight composite and reinforcement materials. The microstructure and chemical compositions of fibers affect the mechanical properties with the fiber cross-sectional area is the most variable influencing the fiber strength. Natural fibers are easy to absorb water due to the presence of hemicellulose that give hydrophilic properties make them less compatible in the interaction with matrix with hydrophobicity properties. Higher cellulose content and crystallinity tend to result better strength properties of fiber while lignin is since versa. Besides that, fiber anatomical characteristics vary between different and same species that affect on the the density and mechanical properties. The other factors namely environmental conditions, method of transportation, storage time and conditions, and fiber extraction affect the size and quality of the natural fibers.
Bacterial cellulose (BC) is an extracellular polymer produced by Komagateibacter xylinus, which has been shown to possess a multitude of properties, which makes it innately useful as a next-generation biopolymer. The structure of BC is comprised of glucose monomer units polymerised by cellulose synthase in β-1-4 glucan chains which form uniaxially orientated BC fibril bundles which measure 3–8 nm in diameter. BC is chemically identical to vegetal cellulose. However, when BC is compared with other natural or synthetic analogues, it shows a much higher performance in biomedical applications, potable treatment, nano-filters and functional applications. The main reason for this superiority is due to the high level of chemical purity, nano-fibrillar matrix and crystallinity. Upon using BC as a carrier or scaffold with other materials, unique and novel characteristics can be observed, which are all relatable to the features of BC. These properties, which include high tensile strength, high water holding capabilities and microfibrillar matrices, coupled with the overall physicochemical assets of bacterial cellulose makes it an ideal candidate for further scientific research into biopolymer development. This review thoroughly explores several areas in which BC is being investigated, ranging from biomedical applications to electronic applications, with a focus on the use as a next-generation wound dressing. The purpose of this review is to consolidate and discuss the most recent advancements in the applications of bacterial cellulose, primarily in biomedicine, but also in biotechnology.
Centralized waste plastic recycling is economically challenging, yet distributed recycling and additive manufacturing (DRAM) provides consumers with direct economic incentives to recycle. This study explores the technical pathways for DRAM of complex polymer composites using a case study of windshield wiper blades. These blades are a thermoplastic composite made up of a soft (flexible) and hard (less flexible) material. The distributed manufacturing methods included mechanical grinding to fused granular fabrication, heated syringe printing, 3-D printed molds coupled to injection molding and filament production in a recyclebot to fused filament fabrication. The particle size, angle of repose, thermal and rheological properties are characterized for the two sub-materials to define the conditions for the extrusion. A successful pathway for fabricating new products was found and the mechanical properties of the resultant components were quantified. Finally, the means to convert scrap windshield wiper blades into useful, high-value, bespoke biomedical products of fingertip grips for hand prosthetics was demonstrated. This study showed that the DRAM model of materials recycling can be used to improve the variety of solutions for a circular economy.
Purpose
The purpose of this paper is to analyse the properties of bacterial cellulose (BC) film, obtained through Kombucha tea fermentation.
Design/methodology/approach
Kombucha fungus was used to produce BC film under static cultivation conditions. Physical and mechanical properties under the influence of drying temperature and durability of BC material were investigated. Tensile properties were estimated by TINIUS OLSEN H10 KT test machine according to ISO 3376:2011, thickness was measured by DPT 60. BC structure was analysed by Scanning Electron Microscopy Quanta 200 FEG.
Findings
BC material with excellent deformation properties in wet state were obtained by fermenting Kombucha tea. Due to the presence of fermentation residues, Kombucha film is sensitive to drying temperature. The best deformation properties retain when BC material is dried at low temperature (about 25°C). BC material becomes stiffer and ruptures at lower deformations due to rapid water evaporation at higher drying temperature. It is confirmed that during time, the properties of BC film changes significantly and there may be problems with the durability of products from this material. BC film has an interesting set of properties, therefore its application to fashion industry without further preparation is limited.
Originality/value
A new approach is based on the evaluation of Kombucha material properties and investigation of BC as new type of material for fashion industry. Some recommendations for Kombucha BC film production are provided, basing on gained experience, experimental results and analysed literature. The advantages and disadvantages of material are discussed in the paper, in order to search for the ways to adapt the new type of material to fashion business.
In the present study, the influence of adding natural fillers to a cellulose acetate (CA) matrix, in order to develop biocomposites, on the properties of the achieved materials has been investigated. Extracted wood flour, holocellulose, and alpha cellulose were used as appropriate fillers. The results of the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) of the fillers and biocomposites suggested the importance of the degree of degradation of filler properties, induced by the chemical treatment necessary for the preparation of the fillers, with emphasis on the content of lignin and the degradation of cellulose. Scanning electron microscopy (SEM) and mechanical analysis revealed that the matrix-filler ratio had a major effect on the prepared CA-based biocomposites, since polarity differences between the two major components caused the reduction of attractive forces in the matrix-filler relation, subsequently altering the properties of the developed materials.
The article presents an experimental study of mechanical properties of cellulose biofilm produced by bacterial fermentation process. Naturally derived biomaterial has great current and potential applications therefore the conditions of material preparation as well as control and prediction of mechanical properties is still a relevant issue. Bacterial cellulose was obtained as a secondary product from Kombucha drink. Presented technique for material preparation and drying is particularly simple and easy to access. The influence of drying temperature (25 °C, 50 °C and 75 °C) on the sample size (thickness and planar dimensions) and mechanical properties (tensile and bursting strength) of cellulose biofilm has been evaluated. It was estimated that during drying biofilm specimens lost up to 92 % of weight and up to 87 % of thickness therefore planar specimen dimensions varied insignificantly. The study showed that the drying temperature is important for optimum strength properties of bacterial cellulose biofilm. The maximum tensile strength (27.91 MPa) was recorded for the samples dried at temperature of 25 °C, when the moisture from the biomaterial is removed gradually and good deformation properties are ensured (respectively tensile extension 18.8 %). Under higher drying temperature biomaterial shows lower values of tensile strength and higher values of bursting strength. The maximum bursting strength (57.2 MPa) was recorded for samples dried at 75 °C when punch displacement changes were insignificant for all tested samples (from 17.8 mm to 21.7 mm).
DOI: http://dx.doi.org/10.5755/j01.ms.25.3.20764
Bio-responsive polymers are the foundation for the construction of the smart systems that exhibit designed biomedical functions after receiving specific stimuli such as biological signals and pathological abnormalities. These stimulus-responsive systems have shown great promise of developing novel products in precision medicine, and relevant research has grown intensively in recent years. This review aims to outline the basic knowledge and recent progress in the advanced bio-responsive systems as well as the major challenges. The current bio-responsive systems mainly rely on physical, chemical and biological cues, and this review focuses on the strategies of molecular design for the incorporation of appropriate responsive building blocks. The potential applications, including controlled drug delivery, diagnostics and tissue regeneration, are introduced and promising research directions that benefit the medical translation and commercialization are also discussed.
Self-assembling manufacturing for natural polymers is still in its infancy, despite the urgent need for alternatives to fuel-based products. Non-fuel based products, specifically bio-polymers, possess exceptional mechanical properties and biodegradability. Bacterial cellulose has proven to be a remarkably versatile bio-polymer, gaining attention in a wide variety of applied scientific applications such as electronics, biomedical devices, and tissue-engi neering. In order to introduce bacterial cellulose as a building material, it is important to develop bio-fabrication methodologies linked to material-informed computational modeling and material science. This paper emphasizes the development of three-dimensionally grown bacterial cellulose (BC) membranes for large-scale applications, and introduces new manufacturing technologies that combine the fields of bio-materials science, digital fabrication, and material-informed computational modeling. This paper demonstrates a novel method for bacterial cellulose bio-synthesis as well as in-situ self-assembly fabrication and scaffolding techniques that are able to control three-dimensional shapes and material behavior of BC. Furthermore, it clarifies the factors affecting the bio-synthetic pathway of bacterial cellulose-such as bacteria, environmental conditions, nutrients, and growth medium-by altering the mechanical properties, tensile strength, and thickness of bacterial cellulose. The transformation of the bio-synthesis of bacterial cellulose into BC-based bio-composite leads to the creation of new materials with additional functionality and properties. Potential applications range from small architectural components to large structures, thus linking formation and materialization, and achieving a material with specified ranges and gradient conditions, such as hydrophobic or hydrophilic capacity, graded mechanical properties over time, material responsiveness, and biodegradability.
Blending of two polymers can result in a number of new composite materials with enhanced properties and applications in several fields. Biopolymers need to be crosslinked in order to modulate their general properties. Chemical crosslinking is a highly versatile method and is generally carried out using aldehydic compounds. Although these are very good cross-linkers, they are not preferred owning to their physiological toxicity. Therefore, the search for natural crosslinking agents is of great interest. Possible candidates are polyphenols, which are widely distributed as minor but functionally important constituents of plant tissues. Thus, this work investigated the use of polyphenols as natural cross-linking agents to produce new materials, namely methylcellulose-chitosan (MC-CS) biocomposites. Two plant–derived polyphenols, i.e. gallic acid (GA) and ferulic acid (FA), were studied as cross-linking agents. FT-IR, DSC, and SEM techniques were used to investigate the formation of the biocomposites. The results showed that only FA can interact with methylcellulose and chitosan as it formed turbid appearance when the clear solutions of MC and plant–derived polyphenols were mixed. The particle size of MC-FA was in the range of 500-600 nm when using 0.5% of polymer and polyphenol compounds. The CS-FA composite possessed relatively large size (6-8 µm) compared to that of the MC one. SEM analysis showed the differences in surface morphology between the cross-linked MC-CS biocomposites and the polymers. The FT-IR and DSC results also indicated that new compounds were formed.
Lignin is a high volume byproduct from the pulp and paper industry, and is currently burned to generate electricity and process heat. The industry has been searching for high value added uses of lignin to improve the process economics. On the other hand, battery manufacturers are seeking non-fossil sources of graphitic carbon for environmental sustainability. In this work, lignin (which is a cross-linked polymer of phenols, a component of biomass) is converted into graphitic porous carbon using a two-step conversion. Lignin is first carbonized in water at 300 °C and 1500 psi to produce bio-char, which is then graphitized using a metal nitrate catalyst at 900-1000 °C in an inert gas at 15 psi. Graphitization effectiveness of three different catalysts, iron, cobalt, and manganese nitrates, is examined. The product is analyzed for morphology, thermal stability, surface properties, and electrical conductivity. Both temperature and catalyst type influenced the degree of graphitization. A good quality graphitic carbon was obtained using catalysis by Mn(NO3)2 at 900 °C and Co(NO3)2 at 1100 °C.
Heart valve and blood vessel replacement using artificial prostheses is an effective strategy for the treatment of cardiovascular disease at terminal stage. Natural extracellular matrix (ECM)-derived materials (decellularized allogeneic or xenogenic tissues) have received extensive attention as the cardiovascular scaffold. However, the bioprosthetic grafts usually far less durable and undergo calcification and progressive structural deterioration. Glutaraldehyde (GA) is a commonly used crosslinking agent for improving biocompatibility and durability of the natural scaffold materials. However, the nature ECM and GA-crosslinked materials may result in calcification and eventually lead to the transplant failure. Therefore, studies have been conducted to explore new crosslinking agents. In this review, we mainly focused on research progress of ECM-derived cardiovascular scaffolds and their crosslinking strategies.
Synthetic biology could offer truly sustainable approaches to the built environment, predict Rachel Armstrong and Neil Spiller.
The current interest in polyphenols has been driven primarily by epidemiological studies. However, to establish conclusive evidence for the effectiveness of dietary polyphenols in disease prevention, it is useful to better define the bioavailability of the polyphenols, so that their biological activity can be evaluated. The bioavailability appears to differ greatly among the various phenolic compounds, and the most abundant ones in our diet are not necessarily those that have the best bioavailability profile. In the present review, we focus on the factors influencing the bioavailability of the polyphenols. Moreover, a critical overview on the difficulties and the controversies of the studies on the bioavailability is discussed.
Biopolymers based hydrogels could have applications in various fields, such as packaging materials, drug delivery systems, biosensors, and agricultural practices. The current work aimed to develop starch/xanthan hydrogels through extrusion and thermopressing processes, using citric acid (CA) as crosslinking agent and sodium hypophosphite (SHP) as catalyst. The hydrogels were produced with different levels of CA (0.00, 0.75, 1.50 and 2.25 g/100 g polymer). Hydration, mechanical, thermal and microstructural properties of the hydrogels were determined. Swelling behavior of the materials with CA was lower than the control. Additionally, CA ensured the preservation of hydrogels integrity after the swelling process. Gel fraction increased with CA 0.75 g/100 g. Starch/xanthan hydrogels crosslinked with CA demonstrated lower strength than non-crosslinked hydrogels, which may be related to acid hydrolysis of the polymer chains. CA-SHP increased the storage modulus of the hydrogels. Reactive extrusion and thermopressing were efficient methods in the production of crosslinked starch/xanthan based hydrogels.
Recent convergence of biotechnological and design tools has stimulated an emergence of new design practices utilizing natural mechanisms to program matter in a bottom-up approach. In this paper, the fibrous network of mycelium—the vegetative part of fungi—is employed to produce sustainable alternatives for synthetic foams. Current research on mycelium-based materials lacks essential details regarding material compositions, incubation conditions, and fabrication methods. The paper presents the results of ongoing research on employing mycelium to provide cleaner architecture and design products with sustainable lifecycles. The paper opens with a critical review of current projects, products, and scientific literature using mycelium in design and architecture. In the second section, material properties of varied fungi-substrate compositions and fabrication methods are evaluated and compared through changes in essential chemical parameters during fermentation, visual impression, water absorbency, and compression strength tests. Then, potential architecture and design implications related to the material properties are discussed. Results indicate a clear correlation between fungi, substrate, mold properties, and incubation conditions on final material characteristics, depicting a clear effect on material density, water absorbency, and the compressive strength of the final bio-composite. Finally, two primary case studies demonstrate implications for mycelium-based composites for circular design and architectural applications. The study shows that in order to produce desirable designs and performance within an inclusive circular approach, parameters such as material composition and fabrication conditions should be considered according to the target function of the final product throughout the design process.
Bacterial cellulose (BC) is an organic compound produced by certain types of bacteria. In natural habitats, the majority of bacteria synthesize extracellular polysaccharides, such as cellulose, which form protective envelopes around the cells. Many methods are currently being investigated to enhance cellulose growth. The various celluloses produced by different bacteria possess different morphologies, structures, properties, and applications. However, the literature lacks a comprehensive review of the different methods of BC production, which are critical to BC properties and their final applications. The aims of this review are to provide an overview of the production of BC from different culture methods, to analyze the characteristics of particular BC productions, to indicate existing problems associated with different methods, and to choose suitable culture approaches for BC applications in different fields. The main goals for future studies have also been discussed here.
A vision is presented on 3D printing with concrete, considering technical, economic and environmental aspects. Although several showcases of 3D printed concrete structures are available worldwide, many challenges remain at the technical and processing level. Currently available high-performance cement-based materials cannot be directly 3D printed, because of inadequate rheological and stiffening properties. Active rheology control (ARC) and active stiffening control (ASC) will provide new ways of extending the material palette for 3D printing applications. From an economic point of view, digitally manufactured concrete (DFC) will induce changes in the stakeholders as well as in the cost structure. Although it is currently too ambitious to quantitatively present the cost structure, DFC presents many potential opportunities to increase cost-effectiveness of construction processes. The environmental impact of 3D printing with concrete has to be seen in relation to the shape complexity of the structure. Implementing structural optimization as well as functional hybridization as design strategies allows the use of material only where is structurally or functionally needed. This design optimization increases shape complexity, but also reduces material use in DFC. As a result, it is expected that for structures with the same functionality, DFC will environmentally perform better over the entire service life in comparison with conventionally produced concrete structures.
This study has been carried out to design novel, environmentally friendly membranes by in situ and ex situ routes based on bacterial cellulose (BC) as a template for the chitosan (Ch) as functional entity for the elimination of copper in wastewaters. Two routes led to bionanocomposites with different aspect and physico-chemical properties. The mechanical behaviour in wet state, strongly related to crystallinity and water holding capacity, resulted to be very different depending on the preparation route although the Ch content was very similar: 35 and 37 wt% for the in situ and ex situ membranes, respectively. The morphological characterization suggested a better incorporation of the Ch into BC matrix through the in situ route. The cooper removal capacity of these membranes was analyzed and in situ prepared membrane showed the highest values, about 50%, for initial concentrations of 50 and 250 mg L⁻¹. Moreover the reusability of the membranes was assessed. This is the first time that the whole 3D nano-network BC membrane is used to provide physical integrity for chitosan to develop eco-friendly membranes with potential applications in heavy metal removal.
Kombucha is a traditional beverage produced by tea fermentation, carried out by a symbiotic consortium of bacteria and yeasts. Acetic Acid Bacteria (AAB) usually dominate the bacterial community of Kombucha, driving the fermentative process. The consumption of this beverage was often associated to beneficial effects for the health, due to its antioxidant and detoxifying properties. We characterized bacterial populations of Kombucha tea fermented at 20 or 30 °C by using culture-dependent and –independent methods and monitored the concentration of gluconic and glucuronic acids, as well as of total polyphenols. We found significant differences in the microbiota at the two temperatures. Moreover, different species of Gluconacetobacter were selected, leading to a differential abundance of gluconic and glucuronic acids.
It is likely that more articles on 3 D Printing (or Additive Manufacturing) have featured in mainstream media over the past two years than during the entire 25 years that the technology has been around. This paper briefly introduces the 3D Printing technology and explains the unique benefits compared to traditional manufacturing methods. Some of the most important reasons why the technology is currently attracting so much attention are discussed. Significant improvements in equipment, materials and software have enabled high end applications for 3D Printed end use parts. This is illustrated by examples of some of the most successful applications. Moving towards real manufacturing also brings new challenges in quality assurance. This paper presents a software solution for data management and quality assurance in 3D Printing. At the same time, low end variants of the technology are becoming more and more affordable for consumers. The question is raised whether people will be printing their own parts at home in the future.
Polypropylene (PP)–microcrystalline cellulose (MCC) composites were prepared containing Poly(propylene-graft-maleic anhydride) (PP-g-MA) and MCC treated with silicone oil, stearic acid or alkyltitanate coupling agent to promote matrix–filler dispersion and compatability. Infrared spectroscopy confirmed surface treatment. MCC content and PP-g-MA increased PP thermal stability and crystallisation temperature (Tc), though reduced crystallinity due to cellulose II crystals. Tensile stress–strain analysis revealed increased modulus with MCC content, PP-g-MA, alkyltitanate and stearic acid. MCC and PP-g-MA reduced creep deformation and increased permanent strain. Storage modulus, loss modulus and glass transition temperature increased with MCC concentration due to effective interaction between PP and MCC.
In recent years, the race for producing biodegradable products has increase tremendously. Different approaches have been attempted to use biomass as natural biopolymer for production of biodegradable plastics. In this work, cellulose was derived from oil palm empty fruit bunch fiber (EFBF) by standard ASTM D1104 method. The cellulose and EFB fibers were blended in different ratios up to 50-wt.% with polypropylene (PP) using Brabender twin-screw compounder. Effects of cellulose and EFB fibers on the mechanical properties of PP were investigated. Studies on the morphological properties and the influence of fiber loading on the properties of PP-cellulose and PP-EFBF composites were also conducted. The PP-cellulose composite gave better results in comparison with PP-EFBF composite. The changes in mechanical and morphological properties with different cellulose and fiber loading were discussed.
Relative molecular size distributions of pectic and hemicellulosic polysaccharides of pea (Pisum sativum cv Alaska) third internode primary walls were determined by gel filtration chromatography. Pectic polyuronides have a peak molecular mass of about 1100 kilodaltons, relative to dextran standards. This peak may be partly an aggregate of smaller molecular units, because demonstrable aggregation occurred when samples were concentrated by evaporation. About 86% of the neutral sugars (mostly arabinose and galactose) in the pectin cofractionate with polyuronide in gel filtration chromatography and diethylaminoethyl-cellulose chromatography and appear to be attached covalently to polyuronide chains, probably as constituents of rhamnogalacturonans. However, at least 60% of the wall's arabinan/galactan is not linked covalently to the bulk of its rhamnogalacturonan, either glycosidically or by ester links, but occurs in the hemicellulose fraction, accompanied by negligible uronic acid, and has a peak molecular mass of about 1000 kilodaltons. Xyloglucan, the other principal hemicellulosic polymer, has a peak molecular mass of about 30 kilodaltons (with a secondary, usually minor, peak of approximately 300 kilodaltons) and is mostly not linked glycosidically either to pectic polyuronides or to arabinogalactan. The relatively narrow molecular mass distributions of these polymers suggest mechanisms of co- or postsynthetic control of hemicellulose chain length by the cell. Although the macromolecular features of the mentioned polymers individually agree generally with those shown in the widely disseminated sycamore cell primary wall model, the matrix polymers seem to be associated mostly noncovalently rather than in the covalently interlinked meshwork postulated by that model. Xyloglucan and arabinan/galactan may form tightly and more loosely bound layers, respectively, around the cellulose microfibrils, the outer layer interacting with pectic rhamnogalacturonans that occupy interstices between the hemicellulose-coated microfibrils.
Algae constitute a largely available, low value material from renewable resources of marine origin to be used for the production of eco-compatible composites. Fibers of the green alga Ulva armoricana from the French coast were positively evaluated for the production of composites with a hydrophilic, eco-compatible polymer, such as poly(vinyl alcohol) (PVA) as continuous matrix by casting of aqueous suspensions and compression molding. PVA, Ulva, and starch were also successfully processed by the melt in the presence of glycerol. Positive results were obtained for film-forming properties and mechanical characteristics also with limited amounts of PVA (40%) attesting for Ulva suitability to be introduced in composites (up to 30%). Degradation in soil of Ulva and an Ulva-based composites outlined a rapid mineralization of Ulva in the selected medium (over 80% in 100 days) while the composite samples underwent a mineralization rate affected by the different component propensity to degradation.
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