Search

Poly(glycerol sebacate) (PGS) is a novel polymeric material intended for applications in tissue engineering (TE). This study involves synthesizing the PGS prepolymer (pPGS) and subsequent manufacturing of porous PGS-based scaffolds with an addition of hydroxyapatite (HAp) by means of thermally induced phase separation followed by thermal cross-linking and salt-leaching (TIPS-TCL-SL). The study aims to investigate the effect of the apatite filler content on properties and morphology of porous PGS/HAp scaffolds. The emphasis is put on the mechanical behavior of the material characterized by means of compression tests and dynamic thermal mechanical analysis (DMTA). In addition to the reference polymer scaffold, the composites with filler contents of 10, 20 and 30 wt% have been examined. Our research revealed that the HAp content does not affect the mechanical properties in a directly proportional manner. The 30 wt% addition of HAp resulted in frayed structure and decrease in the mechanical parameters in comparison to other tested specimens. On the other hand, an addition of 10% did not sufficiently boost the properties. Therefore, a 20% addition of HAp was concluded to have superior mechanical properties in comparison to other analyzed specimens. A similar relationship results from the DMTA studies. Moreover, the strain sweep and frequency sweep tests confirmed the stability of the mechanical parameters in various conditions, as well as the elastomeric nature of the materials. Finally, the material did not exhibit cytotoxicity against standard L929 fibroblasts and cells readily populated the scaffolds. [Display omitted] [ABSTRACT FROM AUTHOR]

This study investigated the effects of poly(butylene-succinate) (PBS) and cassava pulp (CP) at two particle sizes (250 and 400 µm) on the properties of PBS/CP biocomposites. The PBS/CP biocomposites with different ratios (PBS100/CP0, PBS90/CP10, PBS80/CP20, PBS70/CP30, and PBS60/CP40) were prepared using a twin-screw extruder and formed using a ram extruder. The physical, mechanical, and biodegradable properties of these biocomposites were studied. The results showed that the melt flow index of biocomposites significantly decreased with an increase in the CP content as observed in both CP particle sizes. It was also observed that using 400 µm CP in PBS80/CP20 led to a higher melt flow index as compared to using 250 µm CP. The PBS/CP biocomposites were shown to improve Young's modulus and hardness. Nevertheless, tensile strength, elongation at break, and impact strength of the PBS/CP biocomposites decreased with an increase in the amount of CP (in both particle sizes). The addition of 250 µm CP provided good particle dispersion and compatibility in the biocomposite matrix. An increase in the CP content of up to 40% showed that the biocomposites had more brittle fracture although they were also the best biodegradable as indicated by natural soil burial test for 42 days. A biocomposite from PBS/CP could be useful in commodity packaging, outdoor plant pots, and injection molding as eco-friendly, strong and biodegradable materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanostructured Boost: Nano strontium hydroxyapatite (nSrHA) enhances biocomposite strength and stability. • Osteogenic phytochemical-enriched biocomposites show promise for bone regeneration. • Cytocompatibility, controlled release of BM, improved degradation, and increased mechanical strength due to nSrHA incorporation. • Biocomposites significantly boost rADMSC proliferation and viability. • Safe, effective scaffolds ideal for non-load-bearing/maxillofacial reconstructive surgeries. Biocomposite materials, composed of biodegradable polymers and supplements, are promising for bone regenerative matrices due to their mechanical strength and excellent osteoconductivity. This study focuses on fabricating electrospun composite scaffolds using the bark extract of Butea monosperma (BM), nano strontium hydroxyapatite (nSrHA), and polycaprolactone (PCL). Four types of scaffolds were prepared: PCL (control), BM-PCL, nSrHA-PCL, and BM-nSrHA-PCL. The scaffolds were evaluated through various techniques: bright field microscopy for standardization, SEM for structural evaluation, and SEM-EDX for elemental analysis. Additionally, mechanical strength, release study, degradation, and protein adsorption were assessed. Furthermore, cytotoxicity, proliferation, and cytocompatibility of the scaffolds were evaluated using rat adipose-derived mesenchymal stem cells (rADMSCs) through SEM, MTT assay, LDH assay, DAPI staining, and Direct contact assay. SEM analysis confirmed that all four fabricated scaffolds were nano-fibrous in nature. The incorporation of phytochemicals and nSrHA was confirmed via SEM-EDX. Mechanical testing revealed that the BM-nSrHA-PCL scaffolds had superior mechanical properties compared to the control PCL scaffolds. Protein adsorption studies indicated enhanced protein binding in BM-nSrHA-PCL scaffolds. Degradation studies showed that BM-nSrHA-PCL scaffolds had a controlled degradation rate suitable for tissue engineering applications. Cytotoxicity tests confirmed that all scaffolds were noncytotoxic. Proliferation and cytocompatibility assays demonstrated that BM-nSrHA-PCL scaffolds significantly promoted cell proliferation compared to other scaffold types. These results suggest that the BM-nSrHA-PCL scaffolds exhibit improved mechanical properties, protein adsorption, controlled degradation, and enhanced cell proliferation, making them promising candidates for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

Fiber-reinforced green composites made from natural plant fibers are an increasingly popular sustainable alternative to conventional high-performance composite materials. Given the variety of natural fibers themselves, and the even larger variety of possible composites with specific fiber dosage, fiber orientation distribution, fiber length distribution, and fiber–matrix bond characteristics, micromechanics-based modeling is essential for characterizing the macroscopic response of these composites. Herein, an analytical multiscale micromechanics model for elastic homogenization is developed, capable of capturing the variety. The model features (i) a nanoscopic representation of the natural fibers to predict the fiber stiffness from the universal stiffness of the fiber constituents, mainly cellulose, (ii) a spring-interface model to quantify the compliance of the fiber–matrix bond, and (iii) the ability to model any (and any combination of) orientation distribution and aspect ratio distribution. Validation is performed by comparing the predicted stiffness to experimental results for as many as 73 composites available in the literature. Extensive sensitivity analyses quantify the composite stiffening upon increasing fiber volume fraction, fiber alignment, fiber length, and fiber–matrix interface stiffness, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dynamically adjustable mixed and layered hybrid films of nanocellulose and VO 2 nanoparticles were fabricated with simple filtration method. • Thermal and optical stimuli could be used to trigger a reversible change in electrical properties of the films. • Based on simulations, mixed films could be used for reconfigurable intelligent surfaces in 5G and 6G applications. • Layered films acted as smart, gradually switchable electromagnetic interference shields. • The films designed in this study open new possibilities for sustainable future wireless applications. The emerging fields of 5G and 6G telecommunication networks, Internet of Things, and artificial intelligence have intensified the demand for green nanostructured materials with adjustable and intelligent features that respond to external stimuli. By leveraging the insulator-to-metal transition of VO 2 nanoparticles, responsive composite films were developed by integrating these nanoparticles within a biopolymeric network of cationic cellulose nanofibers (CNF+). These films exhibit a reversible change in GHz permittivity upon exposure to thermal or optical stimuli, facilitating dynamic control of their electrical properties. The layered structure of the films further enhances their robustness, featuring a VO 2 nanoparticle core encased within CNF+ layers. This design not only strengthens the structure but also significantly boosts light-induced conductivity, particularly in layered variant, underscoring its potential in optoelectronic applications. Simulation studies reveal that the nonuniform, reconfigurable intelligent surface (RIS) of the developed mixed film adeptly manipulates incident electromagnetic waves, making it suitable for 5G/6G wireless signals. Conversely, the layered film serves as a switchable electromagnetic interference (EMI) shield, demonstrating notable differences in shielding efficiency between its hot and cold states. Consequently, CNF+/VO 2 composite films designed in this work emerge as a versatile, adaptable platform for intelligent electronics, particularly in the realm of 5G/6G wireless communications. [ABSTRACT FROM AUTHOR]

This study intends to analyze the properties and potential applications of a novel composite coating composed of poly (methyl methacrylate) (PMMA) and silver-doped hydroxyapatite (HAPAg) produced from waste eggshells, which was dip-coated onto Ti6Al4V substrates. Medical implants frequently made of the titanium alloy Ti6Al4V can benefit greatly from surface coatings in terms of biocompatibility and performance. In order to add antibacterial and osteoconductive characteristics, silver-doped hydroxyapatite nanoparticles were dispersed within a PMMA matrix to create the PMMA/HAPAg composite coating. The coated samples report an average contact angle (CA) between 70 and 750 and total surface free energy (SFE) between 35 and 50 mJ/m2, which signifies its improved wettability. The 7.03% change in hydrophilicity was observed between PMMA/H0 (75.270 ± 1.690) and PMMA/H20 (700 ± 1.440) coated samples. The increase in adhesion strength and coating thickness with the increase in HAPAg reinforcement was observed. The surface morphology of the defective zones was examined using scanning electron microscopy (SEM), and information on the elemental composition of synthesized was obtained using Inductively Coupled Plasma Mass Spectroscopy (ICPMS), Fourier Transform Infrared spectroscopy (FTIR) and X-ray diffractogram (XRD). Atomic force microscopy (AFM) reveals the surface roughness; root mean square roughness, roughness profile, skewness and kurtosis of the coated samples. The contact angle reports the hydrophilicity and SFE. Finally, the results conclude that the composite coating had a consistent distribution of HAPAg nanoparticles incorporated within the PMMA matrix. The minimal presence of Ag ions on the surface indicates the coating's potential antibacterial properties, and it is highly recommended for dental applications. [Display omitted] [ABSTRACT FROM AUTHOR]

This research explores the innovative fabrication and characterization of recycled polypropylene composites that reinforced by natural fibers, specifically date palm micro fibers (DPF). Employed a twin-screw extruder for the mixing, and injection molding technique for the samples fabrication. DPF was incorporated at varying weight percentages (0, 2, 5, and 10 wt%). A comprehensive analysis, including thermal gravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), was conducted to assess thermal stability, chemical interactions and crystalline structure. Mechanical properties were evaluated through shore-D hardness and uniaxial tensile tests. Notably, the study revealed that an increased DPF filler content resulted in superior mechanical properties, such as enhanced shore-D hardness and tensile strength. This improvement was attributed to the alignment of DPF fillers and the recycled polypropylene matrix. The significance of this research lies in showcasing the promising potential of DPF as an eco-friendly reinforcement material in recycled polypropylene biocomposites, providing a sustainable and environmentally friendly alternative for various engineering applications. The work contributes to advancing greener solutions in material science and highlights the unique advantages of DPF in enhancing composite materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mycelium in SMS proposed as the adhesive for biocomposites production. • Biocomposite with CCS exhibited improved thermal stability property. • Modified chitosan enhanced antimicrobial of biocomposite. • Green adhesive uses decreased global warming potential by 81.22%. Formaldehyde pollution and material shortages are two prominent issues in particleboard production. This study aimed to assess the physical and antimicrobial properties of formaldehyde-free biocomposites produced with mycelium as the adhesive through hot pressing, utilizing spent mushroom substrates. The moduli of elasticity in biocomposites with 20 % chitin-containing substrate and 10 % chitin-containing substrate was determined to be 1383.60 ± 129.31 and 1284.01 ± 66.59 MP, respectively. Following continuous culture for 14 d under 25 °C and moist conditions, the biocomposites produced from chitin-containing spent mushroom substrate, exhibited lower relative abundances of Bacteroides vulgatus and Prevotella copri on the surface of the biocomposites than did 0 % chitin-containing substrate derived biocomposites, which recorded relative abundances of 9.24 % and 9.44 %, respectively. The raw material generation process significantly contributed to various environmental impacts, including land use (44.32 m2 crop eq) and blue water consumption (8.52 m3). The production of biocomposites from spent mushroom substrate is a favourable option for lowering greenhouse gas emissions and reducing the use of toxic chemicals. [ABSTRACT FROM AUTHOR]

Agricultural by-products such as fruits, vegetables, meat, and poultry can pollute the environment, endangering human and animal health. Most agricultural waste is disposed of without treatment before being burned or deposited in landfills. Furthermore, agro waste has the potential to create a slew of new climate-related challenges by emitting more greenhouse gases into the atmosphere regularly. Around 1 billion tons of agro-waste is generated annually, posing a severe problem on several fronts, including the environment and the economy. Thereby, it is essential to effectively use these wastes during industrial operations to pave the way for producing valuable products, which serves as the conceptual framework. For instance, extracting methane from solid waste in Delhi could provide electricity to 18 million residents. Moreover, the global biofuel demand is expected to increase by 11 million gallons between 2021 and 2026. Effectively processing agro waste with rich carbohydrates such as fruit peels, vegetables, sugarcanes, coconut shells, oil palms, maize, and rice husk can produce biofuels. Furthermore, agro-wastes can be used as filler materials in making biopolymers and bio-composites, which serve as greener alternatives to traditional materials. The effective methods for converting agricultural by-products into biofuels, biocomposite materials, bioenergy, and filler materials have been thoroughly discussed in this review. Furthermore, perspectives ways to improve energy efficiency and techniques to reduce environmental impacts are discussed in the present study. [ABSTRACT FROM AUTHOR]

The present examination includes manufacture and portrayal of cryogel bio-composite implants containing chitosan-gelatin (CS-GT), cerium–zinc doped hydroxyapatite (CS-GT/Ce-Zn-HA) by cryogelation technique. The prepared cryogel biocomposites (CS-GT/HA and CS-GT/Ce-Zn-HA) were described by scanning electron microscope (SEM) and X-Ray diffraction (XRD) contemplates. The expansion of Ce-Zn in the CS-GT implants essentially expanded growing, diminished swelling, expanded protein sorption, and expanded bactericidal movement. The CS-GT/Ce-Zn-HA biocomposite had non-toxic towards rodent osteoblast cells. So the created CS-GT/Ce-Zn-HA biocomposite has favorable and potential applications over the CS-GT/HA platforms for bone tissue engineering. [ABSTRACT FROM AUTHOR]

Nano-tricalcium phosphate (n-TCP) is an osteoconductive substance which, like polycaprolactone (PCL), has been used for clinical purposes for many years; It has now been licensed for a range of products for clinical and medication distribution. This research aimed to examine the effects of platelet-rich plasma on mesenchymal stem cell proliferation and osteogenic differentiation. Thus, we decided to examine the in vitro and in vivo actions of PRP-treated porous biocomposite scaffolds based on nano-tricalcium phosphate- polycaprolactone (n-TCP-PCL/PRP). The prepared samples were described utilizing FTIR, XRD, and SEM. MTT has measured the cytotoxicity of the biocomposite scaffolds. After two weeks of cell seeding, Alizarin red staining confirmed bone mineral formation by MSCs cells. Moreover, from day 4 to day 7, n-TCP-PCL/PRP biocomposite scaffold improved the expresses of bone marker genes. Platelet-rich plasma (PRP) in conjunction with nano-tricalcium phosphate- polycaprolactone (n-TCP-PCL) biocomposite scaffold is beneficial for the regeneration and stability of the freshly developed bone tissue. [ABSTRACT FROM AUTHOR]

[Display omitted] • Crosslinked composite of poly (propylene fumarate)-polyurethane with kartogenin modified chitosan was fabricated via free radical polymerization. • Poly (propylene fumarate)-polyurethane improved the mechanical properties of the scaffold. • Chitosan-kartogenin promoted chondrogenic differentiation. • The composites showed good biocompatibility. • The composites offered the desired potential for cartilage tissue engineering. In this research, we explored the development of a cross-linked polymer composite, poly(propylene fumarate)-polyurethane urea (PPFUU), designed to foster the differentiation of human adipose-derived mesenchymal stem cells (hADMSCs) into chondrocytes. PPFUU was synthesized using PPF-diol, 1,6-diisocyanatohexane, and putrescin, which served as the soft section, hard section, and chain extender, respectively. To optimize its characteristics, PPFUU was integrated with a chitosan-kartogenin conjugate (CS-KGN) at varying weight fractions. The blend underwent chemical crosslinking via free radical polymerization, with benzoyl peroxide as the initiator and N-vinyl pyrrolidinone as the crosslinking agent. The resulting composites were rigorously analyzed for different properties, including thermal behavior, hydrophilicity, compressive strength, biocompatibility, and more. Significantly, the introduction of CS enhanced glycosaminoglycan formation. Furthermore, hADMSCs, when cultured in chondrogenic media on the CS-KGN-integrated PPFUU composite, exhibited upregulated SOX9 and aggrecan expression. Based on these in vitro results, the CS-KGN-conjugated PPFUU composite presents a promising avenue for cartilage tissue regeneration. [ABSTRACT FROM AUTHOR]

Bioinorganic cations, that actively involved in many vital cellular activities, have been highlighted in regeneration and repair of tissues recently. However, researchers are still exploring how the sophisticated regulation of these bioactive factors within the microenvironment contribute to the process. Here, we established magnesium oxide homogeneously- and heterogeneously-embedded biocomposites to investigate the biological impacts that result from the different aggregation structure of the bioinorganic element. On the heterogeneous biocomposite, unbalanced microenvironment with erratic ion niche was provided, while stable ionic microenvironment was shown on the homogeneous biocomposite. Compared with the ionic micro-homeostasis, the heterogeneous micron-cluster-created unbalanced niche compromised cellular adhesion and proliferation by restraining the membrane extensions and downregulating the expression of proliferative genes. This unbalanced niche also motivated nonactivated macrophage polarized towards pro-inflammatory phenotype and induced high ratio of necrotic cell death by increasing the intracellular oxidative stress and decreasing the ATP content. After implantation, the homogeneous scaffold promoted tissue healing, whereas the immune responses were deteriorated and prolonged by heterogeneous scaffold, which leading to impaired bone regeneration. This study demonstrated the importance of biocomposite-established magnesium ionic micro - homeostasis on bone tissue regeneration and may inspires the future development of biomaterials. [Display omitted] [ABSTRACT FROM AUTHOR]

• The theory of shear lag model is extended. • Viscoelastic shear lag model is developed to illustrate the mechanical behavior of axon under transient tensile loading. • The paper explains how the vulnerable axons protect themselves from overall damage over the course of evolution. • The paper explains how axons achieve an outstanding mechanical balance of high stiffness and toughness. Axons with staggered microtubules cross-linked by tau protein possess a remarkable mechanical balance of high specific stiffness and toughness. Owing to their viscoelastic nature, axons exhibit stress rate-dependent mechanical behavior, which is relevant to their selective vulnerability to damage in traumatic brain injury. A Kelvin–Voigt viscoelastic shear lag model is developed to elucidate the mechanical responses of axons under transient tensile force. Analytical closed-form expressions are derived to characterize the relative sliding, stress transfer and failure mechanism between microtubule and tau protein while the axon is stretched transiently. The results from the theoretical solutions elucidate how the MT-tau interface length and stress rate affect the mechanical responses of axon. It is found that axonal failure mechanism may be different under different loading conditions. Long microtubules are more vulnerable to rupture at high stress rate, yet short microtubules are likely to detach from microtubule bundles under large deformations. In the view of multi-level failure of axon, it is illustrated how the vulnerable axons protect themselves from overall damage, and how the axon can simultaneously achieve an outstanding mechanical balance of high specific stiffness and toughness. [ABSTRACT FROM AUTHOR]

Abstract This work deals with provision and characterization of the biopolymer-based composites achieved by incorporation of cellulose fibers as the reinforcement within the glycerol plasticized matrix formed by thermoplastic cornstarch biopolymer. The function of starch-based polymers is limited due to poor mechanical properties. However, it is improved with forming a biocomposite of thermoplastic starch (TPS) as matrix and the cellulose fibers (CF) as reinforcement. The surface of cellulose fibers is successfully modified using the air plasma treatment with the aim of improving the matrix/fiber adhesion. The modified fibers are studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The TPS/CF composites are prepared using high friction and hot compression procedure. Tensile test results and SEM images of the fracture surfaces show significant improvement of adhesion between treated cellulose fibers and TPS matrix. Thermogravimetric analysis shows a considerable decomposition at approximately 250–350 °C. XRD proved the significant increase in crystallinity percentage of composites compared to TPS. [ABSTRACT FROM AUTHOR]

Abstract There is a growing incentive within the construction industry to design low energy buildings which incorporate increased levels of insulation whilst also encouraging the use of 'green' materials which have a low environmental impact and can contribute positively to sustainable building strategies. Silica aerogels have received an increasing amount of attention in recent years as a contemporary insulation material, but their wide-spread use is currently hindered by high costs and their high embodied energy. This research project explores the development of a composite insulation material proposed as an alternative to silica aerogel, which consists of natural components including clay and a biopolymer obtained from seaweed known as alginate. Prototype specimens have been developed and characterized in terms of their mechanical properties and microstructure allowing comparisons to be made between five alginate types, each obtained from a different seaweed source. Whilst all of the composites tested offered an improvement over the control sample, the results also demonstrated that the type of alginate used has a significant influence on the compressive strength and modulus values of the resulting composite materials. An analysis of the production process additionally demonstrated that the freeze-drying element can have a significant impact on both the environment and financial costs of producing such a material. [ABSTRACT FROM AUTHOR]

Abstract Biocomposites are promising materials for traditional composites replacement in specific applications due to their interesting properties and sustainability. Although the composite components are manufactured near net shape, some machining operations, commonly drilling, are commonly required prior to mechanical joining of the components. Tool geometry, mainly the point angle of the drill, strongly affects the performance of the drilling process of composites in terms of machining induced damage. The aim of this work is analyzing the influence of the point angle of the drill on the damage generated during drilling of 100% biodegradable composite, using both numerical and experimental approaches. The novelty of the work relies on the lack of studies of drilling 100% biodegradable composites. The influence of the point angle on the thrust forces and hence in the machining induced damage was demonstrated. [ABSTRACT FROM AUTHOR]

Abstract A new approach to manufacture biocomposite sandwich structure is introduced with all materials naturally derived, including jute, flax and cellulose textile as reinforcement skin; mycelium-bound agricultural waste as lightweight cores; and a soy-based bioresin as a matrix. This new material could be used to replace many of the plastic products that are widely used today and therefore preventing the production of waste, while increasing efficiencies in the use of nonrenewable resources. This paper focuses on the final step of the seven-step manufacturing process: resin infusion followed by curing in place for the grown then deactivated mycelium sandwich beams. Specific process details that are highlighted include designing and building the preliminary transparent resin transfer molding for resin flow behavior study, design and fabrication of the aluminum permanent mold prototype, three-point bending flexural tests of the resin infused then cured sandwich beams to determine their strengths, and finally, finite element simulation using Abaqus software to simulate the three-point bending process. To obtain the skin reinforcements' Young's and shear moduli, tensile and V-groove shear tests were performed based on corresponding ASTM standards. It is concluded that although the skin material is the one that carries most of the loads, the strength of the sandwich structure appears to largely depend on the degree of fungal colonization within the core and bonding between the skin and core. The cured resin increased the beams' core shear ultimate stress, core shear yield stress, skin ultimate stress and flexural strengths of the sandwich beams by factors of 1.5–6.5, and the finite element simulation results agreed with the actual situations, which well explained the beams' most common failure mode in flexural bending. [ABSTRACT FROM AUTHOR]

Abstract Porosity of scaffolds plays an indispensable role in tissue regeneration. In this paper, hierarchical scaffolds with tailored macro/micro-porosity architectures for bone tissue engineering applications were introduced. Poly (vinyl alcohol) (PVA) has been innovatively blended into poly (lactic acid) (PLA) to fabricate composite filaments for fused deposition modeling (FDM). Customized macropores (pore size > 100 μm) of scaffolds were designed and precisely fabricated by FDM process. Then the blended scaffolds were subjected to gas foaming process to create micropores (pore size < 10 μm), which are hardly created by using 3DP techniques. Subsequently, PVA phase in the scaffolds was extracted by solvent etching method to create open pores, which are hard to create in gas foaming. The results showed that the scaffolds with 100–800 μm macropores can be precisely fabricated by FDM technique. Meanwhile, 2–10 μm micropores were successfully created. These novel scaffolds have the potential to be used in bone tissue regeneration. [ABSTRACT FROM AUTHOR]

Abstract The mechanical behaviour of conventional composites is usually assumed as linear-elastic up to failure. However, the mechanical behaviour of natural fibres based composites is non-linear with a significant influence of strain-rate. This study presents a FEM model to analyse the impact behaviour of flax/PLA composites. The constitutive model includes the consideration of plastic strains and the influence of strain rate. The model was validated through comparison with low-velocity impact tests. Numerical prediction were in agreement with experimental results conducted with two impactor nose at different impact energies. [ABSTRACT FROM AUTHOR]

Abstract Melting characteristics of high-density polyethylene (HDPE) mixed with nano-size ceramic fillers (hydroxyl apatite and yttria stabilised zirconia) was analysed using the isochronal heating rate between 10 °C min−1 and 80 °C min−1. In this investigation, the kinetics of melting of HDPE-ceramic composites was analysed using the Avrami equation and the Kissinger model, applied to the Avrami formalism. The magnitude of the apparent energy barrier for the melting of HDPE falls within a range of 12 kJ mol−1 and 22 kJ mol−1, with a tendency for heterogeneous melting which was determined by characterising the value of Avrami exponent, n found to vary between 1 and 2. The heterogeneous nature of melting was also confirmed using the scanning electron microscopy, from which the evidences for both nano- and micro-scale interactions of HDPE with ceramic fillers (HA and yttria stabilised zirconia) were confirmed on a microscopic scale. [ABSTRACT FROM AUTHOR]

Water contaminated by cytostatic drugs has many negative impacts on the ecosystems. In this work, cross-linked adsorbent beads based on alginate and a geopolymer (prepared from an illito-kaolinitic clay) were developed for a promising decontamination of the 5-fluorouracil (5-FU) cytostatic drug from water samples. The characterization of the prepared geopolymer and its hybrid derivative was performed by scanning electron microscopy, X-ray diffraction, Fourier transform infrared and termogravimetric analysis. Batch adsorption experiments indicated that alginate/geopolymer hybrid beads (AGHB) allow an excellent 5-FU removal efficiency of up to 80% for a dosage adsorbent/water of 0.002 g/mL and a concentration of 5-FU of 2.5 mg/L. The adsorption isotherms data follow well the Langmuir model. The kinetics data favor the pseudo-second-order model. The maximum adsorption capacity (q max) was 6.2 mg/g. The optimal adsorption pH was 4. Besides pore filling sorption process, the carboxyl and hydroxyl groups from alginate immobilized onto the geopolymer matrix favored the retention of 5-FU ions by hydrogen bonds. Common competitors, such as dissolved organic matter, do not significantly affected the adsorption. In addition, this material has not only eco-friendly and cost-effective advantages but also excellent efficiency when applied to real environmental samples such as wastewater and surface water. This fact suggests that it could have a great application in the purification of contaminated water. [Display omitted] • Alginate/geopolymer hybrid beads were synthetized using extrusion method. • >80% of 5-FU in a 2.5 mg/L solution was removed with a dosage of 0.02 g AGHB/10 mL. • The adsorption equilibrium was reached very fast (<60 min). • 5-FU adsorption onto AGHB is well described by the Langmuir model and PSO model. • High potential of AGHB to be used in environmental contaminated water. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel inverse biological crossed-lamellar structure was synthesized in CFRP. • This is the first non-biological prototype crossed-lamellar structure in the literature. • The tailored inverse-biologic crossed-lamellar structure is designed to achieve higher load-carrying capacity and stiffness. The remarkable toughness of Strombus gigas shell arises from its microstructure. In this study, inspired by the biologic crossed-lamellar microstructure of Strombus gigas shell, we prepared a novel carbon fiber reinforced polymer (CFRP) composite with inverse-biologic crossed-lamellar structure by replacing the inner and outer layers with the "tough" middle structure. The influences of the alternating arrangement of crossed-lamellar three-layer structure on the mechanical responses, including toughening mechanisms and biological mechanism, were studied. Experimental and numerical results indicated that as burrowing mollusks, Strombus gigas shells require a balance of certain load-carrying capacity and stronger protection function. Meanwhile, the tailored inverse-biologic structure achieved higher load-bearing capacity and stiffness. Additionally, the Bouligand-ply design strategy was proposed as an alternative to the traditional angle-ply design for the crossed-lamellar structure. By changing the laying-up form and pitch angle of the middle layer, a significant improvement in both load-bearing and energy dissipation capacity of the structures was achieved. The paper provides valuable insights for the design of high-performance biomimetic crossed-lamellar structures and holds great potential for the customization of fiber-reinforced composites. [ABSTRACT FROM AUTHOR]

State-of-the-art workflows within Architecture, Engineering, and Construction (AEC) are still caught in sequential planning processes. Digital design tools in this domain often lack proper communication between different stages of design and relevant domain knowledge. Furthermore, decisions made in the early stages of design, where sketching is used to initiate, develop, and communicate ideas, heavily impact later stages, resulting in the need for rapid feedback to the architectural designer so they can proceed with adequate knowledge about design implications. Accordingly, this paper presents research on a novel integrative design framework based on a recently developed 4D sketching interface, targeted for architectural design as a form-finding tool coupled with three modules: (1) a Geometric Modelling module, which utilises Points2Surf as a machine learning model for automatic surface mesh reconstruction from the point clouds produced by sketches, (2) a Material Modelling module, which predicts the mechanical properties of biocomposites based on multiscale micromechanics homogenisation techniques, and (3) a Structural Analysis module, which assesses the mechanical performance of the meshed structure on the basis of the predicted material properties using finite element simulations. The proposed framework is a step towards using material-informed design already in the early stages of design. [ABSTRACT FROM AUTHOR]

Abstract Poly (butylene adipate-co-terephthalate)/thermoplastic starch (PBAT/TPS) blends and a PBAT/TPS/babassu mesocarp biocomposite were prepared by melt mixing in a torque rheometer at different processing temperatures (150, 170, 190 °C). Tensile test specimens were obtained by hot pressing. Torque rheometry indicated that molecular weight decreased with increasing processing temperature and TPS content in the blend, and this decrease was more intense with babassu mesocarp addition. PBAT mechanical properties were hardly affected by processing temperature while those of the blends decreased with thermoplastic starch content. Overall, increasing processing temperature led to lower mechanical properties, particularly at 190 °C. Fiber addition led to higher modulus and lower strength and elongation at break than the corresponding blend at all processing temperatures investigated. The differences observed on blend morphology as a function of processing temperature were minor. Some adhesion between TPS and PBAT is observed but adhesion between polymer matrix and babassu fibers is essentially non-existent. Highlights • PBAT/TPS and its biocomposite properties were processed at different temperatures. • Higher temperatures reduced the molecular weight of the samples. • PBAT properties were nearly insensitive to processing temperature. • Optimal properties were obtained for the samples processed at 170 °C with 20% TPS. • Babassu mesocarp showed low affinity with PBAT leading to lower elongation. [ABSTRACT FROM AUTHOR]

Transparent wood (TW) structures in research studies were either thin and highly anisotropic or thick and isotropic but weak. Here, transparent plywood (TPW) laminates are investigated as load-bearing biocomposites with tunable mechanical and optical performances. Structure-property relationships are analyzed. The plies of TPW were laminated with controlled fiber directions and predetermined stacking sequence in order to control the directional dependence of modulus and strength, which would give improved properties in the weakest direction. Also, the angular dependent light scattering intensities were investigated and showed more uniform distribution. Luminescent TPW was prepared by incorporation of quantum dots (QDs) for potential lighting applications. TPW can be designed for large-scale use where multiaxial load-bearing performance is combined with new optical functionalities. [ABSTRACT FROM AUTHOR]

The suitability of three local lignocellulosic wastes i.e. almond shell (AS), rice husk (RH) and seagrass (SG) as fillers in PHB/Fiber composites applications has been studied. PHB/Fiber composites with 10 phr and 20 phr fiber content were prepared by melt blending. The influence of the fiber type (size, morphology and origin) and content on the morphological, mechanical and thermal properties of the as obtained composites has been assessed. To evaluate the potential use in food packaging applications, the barrier performance to water, thermoforming ability and disintegration in controlled composting conditions of the composites were also studied. All the fibers have demonstrated to be apt for their use as fillers in PHB/Fiber composites, showing a reinforcing effect without affecting the crystallinity and the disintegration rate of PHB. The thermal stability and the water barrier performance of the composites were reduced by the presence of the fibers. Nevertheless, the addition of AS resulted in the best balance of properties, in terms of permeability and mechanical properties, finding an enhancement of the thermoforming ability of PHB when 10 phr of AS was added. [ABSTRACT FROM AUTHOR]

Nanostructured materials are difficult to prepare rapidly and at large scale. Melt-processed polymer-clay nanocomposites are an exception, but the clay content is typically below 5 wt%. An approach for manufacturing of microfibrillated cellulose (MFC)/kaolinite nanocomposites is here demonstrated in pilot-scale by continuous production of hybrid nanopaper structures with thickness of around 100 μm. The colloidal nature of MFC suspensions disintegrated from chemical wood fiber pulp offers the possibility to add kaolinite clay platelet particles of nanoscale thickness. For initial lab scale optimization purposes, nanocomposite processing (dewatering, small particle retention etc) and characterization (mechanical properties, density etc) were investigated using a sheet former (Rapid Köthen). This was followed by a continuous fabrication of composite paper structures using a pilot-scale web former. Nanocomposite morphology was assessed by scanning electron microscopy (SEM). Mechanical properties were measured in uniaxial tension. The fire retardancy was evaluated by cone calorimetry. Inorganic hybrid composites with high content of in-plane oriented nanocellulose, nanoclay and wood fibers were successfully produced at pilot scale. Potential applications include fire retardant paperboard for semi structural applications and as reinforcement mats in molded thermoset biocomposites. [ABSTRACT FROM AUTHOR]

Aligning the sustainability in construction process can be achieved through material selection process with low impact on environment and human health. Today, biocomposite materials are investigated and developed to replace with none, and less eco-friendly materials used in the construction industry leading to emergence of next generation of sustainable and green building materials. This paper aims to develop a model of fully hybrid bio-based biocomposite based on Life Cycle Assessment (LCA), and comparing it with fully petroleum-based composite, which are common conventional building materials. The methodology framework of this research is determined based on ISO 14040 and 14044. Also, the ReCiPe as the common method in SimaPro software is chosen for appraising and comparing LC impact assessment (LCIA). This research highlights the negative effect of these kinds of building materials with providing single scores coming from three gauges including Human Health, Ecosystems and resources. It is observed that substituting the biocomposite with the fully petroleum-based composite has led to a decline of about 30% in single score outcome. The significance of this research is related to important judgement information to policy makers and the prospective manufacturers in the commercialization phase of this new biocomposites as sustainable and green building materials. [ABSTRACT FROM AUTHOR]

The purpose of this article is to understand the influence of typical composite parameters (interfacial bond strength, surface-area and fibre mechanical properties) on the tensile properties of nonwoven composite materials. The materials investigated were flax, hemp and Poly-(propylene) (PP) and Maleic Anhydride-grafted PP (MAPP), which provide different configurations in terms of fibre mechanical properties, bundle individualization and fibre/matrix interface. Whereas hemp fibres exhibit poorer tensile properties and lower bundle individualization than flax fibres, their higher lignin content evaluated by FT-IR analysis improves the interfacial shear strength (IFSS) with PP and MAPP. However, the tight interface developed with hemp fibres has only a weak effect at the scale of composites. With low-IFSS systems such as plant fibres associated with polyolefin matrices, mechanical properties at the macroscale are governed by the fibre mechanical properties and bonding area rather than by the interfacial bond strength. [ABSTRACT FROM AUTHOR]

A biocomposite production system (BPS) contains a wide range of elements that are vulnerable to internal as well as external factors that may stimulate a system to be disrupted. Hence, there is a need to manifest resiliency in order to withstand the inevitable change without affecting its robustness and stability. The three aspects of a resilient BPS are interconnectivity, adaptability and transformability. The interconnectivity concept deals with the reliability and effectiveness of the supply chain network and production systems’ resourcefulness. The adaptability aspect reinforces the agility and adjusting capacity of a system towards versatility and flexibility across the range of elements involved in the production system. Transformability deals with the capacity of a system to alter into a new system based on research, innovation and creativity. Therefore, the core aspects of resiliency in a BPS would result in increased stability and effectiveness. System dynamics models have been developed depicting the cause and effect of each of the three aspects. Finally, a model has been presented which could enable researchers and organizations to take guided decision towards a more robust and resilient BPS. [ABSTRACT FROM AUTHOR]

Starch high biodegradation is a limitation for commercialization of starch derived slow release fertilizers (SRFs). To reduce starch biodegradation, kraft lignin (5%–20%) was tested for reducing the starch biodegradability in urea crosslinked starch (UcS) films, reported as here as a SRF. Biodegradability tests were conducted under anaerobic soil microcosm for period of 60 days. Fourier transformed infrared spectroscopy results showed an absence of peak at 1776 cm −1 (pertained to oxidation of starch) in biodegraded lignin reinforced films. Thermogravimetric analysis of lignin reinforced films showed deceleration in the biodegradability rates, which were clearly evident from increase in the decomposition temperature at 5% weight loss, ∼67.0 °C and at maximum weight loss, ∼13.6 °C. Besides, char contents were increased, ∼11.3%. Molecular weight distribution indicated the lignin's effect on conservation the molecular weight and polydispersity of starch in films. Lignin role in protecting the starch morphology was confirmed through optical microscopy results, which showed a less change for feret mean and particle area of starch particles. Further, lignin increased average roughness, ∼1.04 to 4.76 times for biodegraded films, possibly due to accumulation of lignin after loss of starch in films. Further, this study concluded that lignin influenced effectively the reduction in starch biodegradability under anaerobic soil microcosm. Thus, lignin could be used in urea crosslinked starch and other similar films, for controlling the starch biodegradability and improving the SRF formulations. [ABSTRACT FROM AUTHOR]

Biocomposites have a high potential to be ecofriendly and sometimes technically competitive with conventional composites and plastics. Nevertheless, studies are inconclusive about the relative economic and environmental performance of these materials. In this study, biocomposite materials made with banana fiber extracted from Colombian region plantation were evaluated by Life Cycle Assessment and Life Cycle Cost methodologies from cradle to manufacturing. Banana fiber-based composites combinations were compared with polyester resin. The results show the biocomposites alternatives perform globally worse than polyester and are highly dependent of the percentage of resin, type of fiber treatment and to the presence kaolinite. [ABSTRACT FROM AUTHOR]

This work deals with fibrous biocomposites prepared by using nettle and poly(lactic acid) fibers and employing carding and compression-molding processes. The role of carding process in determining the tensile strength of the biocomposites was analyzed. The tensile, bending and impact properties of the biocomposites were found to increase initially with the increase of nettle fiber content till 50 wt% and decrease afterwards. The thermogravimetric analysis inferred that the thermal stability of the biocomposites increased with the increase of nettle fiber content. The dynamic mechanical analysis showed that the biocomposites exhibited high storage modulus, low loss modulus, and low damping factor. Further, the biocomposites exhibited excellent biodegradability and their biodegradability increased with the increase of nettle fiber content. Overall, the biocomposite prepared with equal weight proportion of nettle and poly(lactic acid) showed high potential for automotive dashboard panel application. [ABSTRACT FROM AUTHOR]

Three-dimensional multicellular human bone marrow mesenchymal stem cells (hBM-MSCs) are showing a great promise in the repair of bone tissue due to its osteogenic differentiation potential, mimicking in vivo microenvironment and immunomodulatory property. In the present study, the potential of hBM-MSC microtissues (MTs) in combination with a biocomposite material to form vascularized bone-like tissue at an ectopic site in an immunocompromised mouse was evaluated. The scaffold was fabricated using gelatin, carboxymethyl cellulose, polyvinyl alcohol and nano-hydroxyapatite (GCnHP) by the freeze-drying method. The physico-chemico-biological characteristics were compared with control scaffold devoid of polyvinyl alcohol (GCnH). The scaffolds (GCnH and GCnHP) were highly porous and had interconnected pores. GCnHP showed higher mechanical strength, higher water adsorption and a lower rate of collagenase-mediated degradation in comparison to GCnH. The scaffolds also supported growth and proliferation of hBM-MSCs MTs and subsequent differentiation into osteoblast-like cells. The differentiated cells showed matrix mineralization and high expression of runX2, alkaline phosphatase, collagen type 1 and osteocalcin genes. A high expression of VEGF was also observed suggesting the potential of hBM-MSC MTs to induce angiogenesis. H&E and Masson's trichrome staining of the 4-weeks in vivo implanted scaffold revealed the presence of newly synthesized collagen and infiltration of host vasculature. IHC assessment showed expression of osteocalcin and osterix. These results demonstrate the efficacy of the combination of hBM-MSC MTs and biocomposite material as a promising approach for in vivo non-load bearing bone tissue repair for future clinical and various regenerative medicine applications. [ABSTRACT FROM AUTHOR]

Natural fibers are not as rigid as glass or carbon fibers. During composites extrusion and injection molding, they tend to bend and twist in the polymeric matrix, thus resulting in fiber waviness and decreased mechanical properties of natural fiber composites. The most widely used models for the estimation of interfacial shear strength (IFSS) and elastic modulus, which consider the fiber aspect ratio and mechanical properties of the fiber and matrix, do not consider these important features. In order to account for fiber waviness, an effective fiber length is proposed in this paper. The undulation of the fibers is approximated with a sinusoidal arc along with a calculated new length. The proposed correction factor depends on the wavelength and amplitude of the wave approximating the fiber. To verify this method, blends of polylactic acid (PLA) and polycarbonate (PC) (prepared with and without an interchange reactions catalyst) with addition to various percentages of cellulosic fibers (5 wt%, 10 wt% and 15 wt%) have been prepared and characterized. It has been demonstrated that by considering the corrected length values, it is possible to predict the mechanical properties and the effective reinforcement attained in the composites by using the most widely used models. In particular, the prediction of the elastic modulus is slightly affected by this correction, whereas the calculation of IFSS is strongly dependent on it. [ABSTRACT FROM AUTHOR]

This study investigated mechanical properties of biocomposites developed from recycled polylactic acid (PLA) from packaging industry and treated cellulosic fibers from pulp and paper solid waste. Microwave and enzymatic treatments were used for extraction and surface modification of hydrophilic cellulosic fibers. Enzymatic treatment was specifically performed for activation of hydroxyl groups and improvement of adhesion between matrix and fibers including controlling the length of cellulosic fibers with size reduction of around 50% (142 and 127 μm for primary and mixed biosolids, respectively) as compared to microwave treatment. Microwave treatment produced cellulosic fibers of 293 and 341 μm, for primary and mixed biosolids, respectively. Mechanical properties of biocomposites with 2% (w/w) of treated cellulosic fibers (Young's Modulus 887.83 MPa with tensile strain at breakpoint of 7.22%, tensile stress at yield 41.35 MPa) was enhanced in comparison to the recycled PLA (Young's Modulus 644.47 ± 30.086 MPa with tensile strain at breakpoint of 6.01 ± 0.83%, tensile stress at yield of 29.49 ± 3.64 MPa). Scanning electron microscopy revealed size reduction of cellulosic fibers. X-ray diffraction and Fourier transform infrared spectroscopy confirmed strong mechanical properties of novel biocomposites. [ABSTRACT FROM AUTHOR]

Biocomposites, and generally bio-based plastics, are seen as a promising alternative to conventional plastics because they are based on renewable natural components (eco-friendly) with a lower cost. Biocomposites using soy protein and glycerol were obtained with an injection moulding technique as the thermoprocessing method. Nanoclay (Montmorillonite, MMT-Na + ) was included to improve physicochemical properties of novel SPI/MMT nanocomposites prepared by injection moulding, primary attending to water uptake capacity (WUC), but also considering rheological and mechanical properties. The influence of processing conditions has been studied in order to assess the modifications taking place in the microstructure and properties of these nanocomposites. Addition of MMT-Na + improves mechanical properties and WUC of SPI-based materials, depending on processing conditions. Injection pressure only exerts a slight enhancement of mechanical properties and WUC. However, an increase in mixing time leads to a relevant increase in WUC without impairing the mechanical properties of nanocomposites. [ABSTRACT FROM AUTHOR]

Biomass-derived carbon has attracted extensive attention because of its unique form, wide range of sources and low cost. However, the construction of efficient biomass-based microwave absorbers with hierarchical structures and multicomponent magnetic/dielectric structures remains a great challenge. Therefore, CoNi-MOF was self-assembled in situ on the plant Juncus effusus by the microwave method, and CoNi/NC/C composites were prepared by in situ pyrolysis in a nitrogen atmosphere. The morphology, electromagnetic parameters, specific surface area and porous structure of the composites were adjusted by controlling the pyrolysis temperature. For a pyrolysis temperature of 600 ℃ and filling of 16 wt%, the composite was found to show an RL min value of − 64.3 dB at 12.88 GHz at a thickness of 2.5 mm, and the effective absorption bandwidth (EAB)reached 7.36 GHz. The excellent microwave absorption performance was attributed to conduction loss, dipole polarization, interface polarization, magnetic loss and balanced impedance matching. • Multimodal 3D structure CoNi / NC / C composites were synthesized by microwave and pyrolysis. • The RLmin of the sample was − 64.3 dB at 2.5 mm, with a broad effective bandwidth of 7.36 GHz. • Metal-O-C and Metal-N bonds were present in the composites. • The performance derives from multiple loss mechanism and tunable impedance match. [ABSTRACT FROM AUTHOR]

[Display omitted] Plastic pollution has become a global threat to humanity. Fortunately, humanity has always found ways of overcoming such threats through multipronged approaches. To overcome this current threat brought about by anthropogenic linear pattern of take-make-use-dispose of fossil-based plastics, an intentional approach of adopting biobased plastics which are renewable has taken shape. In this approach, governments, industry, and academia are at the forefront of making determined commitments to slow down the spiralling carbon footprint and aim at net zero carbon emissions by 2050. In this regard, PHAs which have a rich resume of desired properties to replace non-renewable fossil-based plastics are increasingly becoming popular. However, PHA production cost is still high compared with the fossil-based plastics and there exists properties performance gap because they are typically brittle, especially the short chain length PHAs (Scl-PHAs). Considerable efforts are geared towards tuning the mechanical properties as well as reducing the cost to meet the market requirements. The most authentic way of tackling these twin-challenges of reducing the cost of PHA products and their properties enhancement is the incorporation of fillers sourced from renewable sources, especially the plant biomass. In this comprehensive review, Scl-PHAs biopolymers are discussed, their modifications with plant biomass (natural fibres and components, agro-residues, and industrial residues) are elucidated. Moreover, their wide scope of applications, sustainability performance (biodegradation studies) and other viable end-of-life options are amply discussed. Finally, we draw conclusions and highlight future opportunities in this exciting bioplastic area. [ABSTRACT FROM AUTHOR]

Disposable containers made of non-biodegradable polymers are considered as one of the most prevalent environmental pollutants. It is very important and desirable to make fully biodegradable disposable containers for food packaging that does not endanger the health of consumers. In this research, fully biodegradable polymer composites were prepared by melt mixing of polylactic acid (PLA), polybutylene succinate (PBS), and natural polymers including corn starch and wheat straw, and their physical and mechanical properties were evaluated. For this purpose, by conducting experiments according to the optimal custom mixture design of the response surface methodology, the effect of 3 independent variables including the concentration of the PLA and PBS biopolymers blend (50/50% w/w) (CBB) in the range of 30–70, the concentration of corn starch (CCS) in the range of 30–60 and the concentration of wheat straw (CWS) in the range of 0–8 wt percentage of biocomposite on the dependent variables including the elastic modulus (EM), elongation at break (EB), impact strength (IS) and equilibrium moisture content (EMC) of the biocomposite sheet were investigated. According to the results of this research, with the increase in the concentration of corn starch and wheat straw in the studied range, the EM and EMC of the biocomposite increased, while its EB and IS decreased. According to the results obtained from optimizing the effects of independent variables on the physicomechanical properties of the biocomposite sheet, the optimal values predicted by the models for CBB, CCS and CWS were 48.2 wt%, 45.4 wt%, and 6.4 wt%, respectively and predicted values for EM, EB, IS and EMC were 80.8 MPa, 11.4%, 2 kJ/m2 and 4.1%, respectively. Also, the biodegradability rate of the biocomposite with the optimal formulation was 71.1% in the fifth month of the test. • Biocomposites of biopolyester blend filled with two natural polymers were prepared. • Biocomposites contained polylactic acid, polybutylene succinate, starch, and wheat straw. • Constituents concentration had main effects on the sheet's physicomechanical properties. • Optimal sheet contains 48.2 wt% biopolyester blend and 51.8 wt% natural polymers. • The biocomposite sheet with optimal formulation had a high degree of biodegradability. [ABSTRACT FROM AUTHOR]

In this paper, analytical and 3D numerical models are developed to investigate the mechanical behavior of sandwich pipe under internal pressure loading. The suggested models provide an exact solution for stresses, strains and displacement on the sandwich pipe, which is made of epoxy material for the core layer and reinforced materials with an alternate-ply for the skin layers. The aim of this analysis is to evaluate the potential applications of jute and pineapple leaf fiber (PALF) bio-fibers in order to replace glass synthetic fibers generally employed in sandwich pipes. In this subject, a failure analytical analysis was developed using TSAI-WU criterion. The results of stress, strain and displacement distribution through the thickness are presented for the analytical and numerical models. The comparison between the both models results show a very good agreement. In order to increase the rigidity of a biocomposite sandwich and reduce the gap compared with a synthetic sandwich, a gradual reinforcing of layer numbers was chosen, which permitted the best behavior. The ultimate pressure and safety factors obtained by increasing biocomposite layers are significant for composite transportation pressure pipelines, especially for sandwich pipe based on PALF/epoxy. • We aim at modeling a sandwich pipe under internal pressure loading using analytical and 3D numerical models for failure analysis. • The structure is a made of epoxy material for the core layer and reinforced materials with an alternate-ply for the skin layers. • Evaluate the potential applications of bio-fibers in order to replace synthetic fibers generally employed in sandwich pipes using TSAI-WU criterion. • Substituting synthetic fibers by bio-fibers yields a satisfactory result by increasing the number of layers. [ABSTRACT FROM AUTHOR]

In the present study, we aimed at fabricating an osteoinductive biocomposite scaffold using keratin obtained from human hair, jellyfish collagen and eggshell-derived nano-sized spherical hydroxyapatite (nHA) for bone tissue engineering applications. Keratin, collagen and nHA were characterized with the modified Lowry method, free-sulfhydryl groups and hydroxyproline content analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and thermal gravimetric analysis (TGA) which confirmed the success of the extraction and/or isolation processes. Human adipose mesenchymal stem cells (hAMSCs) were isolated and the cell surface markers were characterized via flow cytometry analysis in addition to multilineage differentiation capacity. The undifferentiated hAMSCs were highly positive for CD29, CD44, CD73, CD90 and CD105, but were not seen to express hematopoietic cell surface markers such as CD14, CD34 and CD45. The cells were successfully directed towards osteogenic, chondrogenic and adipogenic lineages in vitro . The microarchitecture of the scaffolds and cell attachment were evaluated using scanning electron microscopy (SEM). The cell viability on the scaffolds was assessed by the MTT assay which revealed no evidence of cytotoxicity. The osteogenic differentiation of hAMSCs on the scaffolds was determined histologically using alizarin red S, osteopontin and osteonectin stainings. Early osteogenic differentiation markers of hAMSCs were significantly expressed on the collagen-keratin-nHA scaffolds. In conclusion, it is believed that collagen-keratin-nHA osteoinductive biocomposite scaffolds have the potential of being used in bone tissue engineering. [ABSTRACT FROM AUTHOR]

A study of the impact behaviour and the post-impact residual strength of fully biodegradable composites is presented in this work. To this end, low-velocity impact tests and compressive residual strength tests were carried out on flax/PLA laminates. The results were compared with carbon/epoxy laminates, showing some important advantages in terms of absorbed energy and normalized residual strength. The reason was attributed to different energy absorption mechanisms; the main failure mode in flax/PLA laminates is fibre failure while residual strength of carbon/epoxy laminates is dominated by delaminations. [ABSTRACT FROM AUTHOR]

Composite materials based on renewable agricultural and biomass feedstocks are increasingly utilized as these products significantly offset the use of fossil fuels and reduce greenhouse gas emissions in comparison with conventional petroleum-based materials. However, the inclusion of natural fibers in polymers introduces several challenges, such as excess water absorption and poor thermal properties, which need to be overcome to produce materials with comparable properties to the conventional composite materials. Instead of using rather expensive chemical and physical modification methods to eliminate these aforementioned challenges, a new trend of utilizing waste, residues, and process by-products in natural fiber-polymer composites (NFPCs) as additives or reinforcements may bring considerable enhancements in the properties of NFPCs in a sustainable and resilient manner. In this paper, the effects of waste materials, residues or process by-products of multiple types on NFPCs are critically reviewed and their potential as NFPC constituents is evaluated. [ABSTRACT FROM AUTHOR]

Nacre-mimetic biocomposites made from the combination of montmorillonite clay and the hemicellulose xyloglucan give materials that retain much of their material properties even at high relative humidity. Here, a model composite system consisting of two clay platelets intercalated by xyloglucan oligomers was studied at different levels of hydration using molecular dynamics simulations, and compared to the pure clay. It was found that xyloglucan inhibits swelling of the clay at low water contents by promoting the formation of nano-sized voids that fill with water without affecting the material’s dimensions. At higher water contents the XG itself swells, but at the same time maintaining contact with both platelets across the gallery, thereby acting as a physical cross-linker in a manner similar to the role of XG in the plant cell wall. [ABSTRACT FROM AUTHOR]

Wetting properties and capillary parameters are of first interest for composite and especially bio-composite manufacturing, interface compatibility between reinforcement and matrix, and durability. Few studies have been dedicated in literature to continuous textile fibers and uncured liquid resins wetting properties, and particularly the methods used may be ambiguous, revealing a wide dispersion in results. In this work a reliable method is proposed to determine properly the wetting properties of fibers and some resins commonly used for composite applications. Firstly, a procedure to characterize dispersive and polar components of surface tension for an epoxy and a partially bio-based resin with a tensiometer is proposed. Then a new method was applied on single fibers of semi-synthetic cellulose (viscose), which allows deriving representative values of contact angles from a series of measurements, minimizing the measurement scatter even when using a conventional tensiometer. Resin components and contact angles between cellulose fibers and test liquids, including resins, led to characterize dispersive and polar components of fiber surface energy. [ABSTRACT FROM AUTHOR]