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The mechanical properties of natural fibers, as used to produce sustainable biocomposites, vary significantly—both among different plant species and also within a single species. All plants, however, share a common microstructural fingerprint. They are built up by only a handful of constituents, most importantly cellulose. Through continuum micromechanics multiscale modeling, the mechanical behavior of cellulose nanofibrils is herein upscaled to the technical fiber level, considering 26 different commonly used plants. Model-predicted stiffness and elastic limit bounds, respectively, frame published experimental ones. This validates the model and corroborates that plant-specific physicochemical properties, such as microfibril angle and cellulose content, govern the mechanical fiber performance. [ABSTRACT FROM AUTHOR]

Green nanocomposites based on polylactic acid (PLA) and Wood Flour (WF) with different loadings of graphene nanoparticles (GNPs) were produced by compressing molding process. The mechanical strength, dimensional stability, and viscoelastic behavior of nanocomposites were characterized by static mechanical analysis (flexural and tensile), water uptake, and dynamic mechanical analysis (DMA) tests. Results indicated that the incorporation of GNPS into the fabricated samples, significantly improved the mechanical properties of the composites. However, the water absorption and thickness swelling of the composites progressively decreased with increasing GNPs content. In general, the specimens filled with GNPs showed the highest values of storage and loss modulus compared with the other ones, due to the highest interaction taking place at the matrix–filler interface. Morphological images show that the GNPs were homogeneously and well-dispersed in the composites. Based on the findings obtained from the present study, it can be said that the optimum content of GNPs for the fabricated WPC samples is 2%. [ABSTRACT FROM AUTHOR]

This study explores the possibility of developing a new class of hybrid particulate-filled biocomposites using wood flour and rice husk wastes as environmentally friendly additives to poly(lactic acid) (PLA) as matrix material. Samples were prepared with fillers of different concentrations (0, 2.5, 5, 7.5 and 10 wt %), while the ratio of wood flour and rice husk was fixed at 1:1 in all cases. The preparation of biocomposites was performed through extrusion using a twin-screw extruder. Subsequently, they were formed into specimens by injection molding. Mechanical, thermal, thermomechanical, and morphological properties were examined. The addition of natural waste particles resulted in a remarkable improvement both in tensile and flexural modulus; however at a cost of impact strength and tensile strength. Meanwhile, flexural stress at conventional strain values were barely affected by the presence of wood flour and rice husk. The SEM images confirmed that there is a limited interfacial adhesion between the components, which supports the results obtained during mechanical tests. Both the differential scanning calorimetry (DSC) and the dynamic mechanical analysis indicated that the glass transition temperature of PLA was not affected by the incorporation of filler particles; however, the crystalline structure was gradually altered with increasing filler loading according to the DSC. Additionally, the particles were observed acting as nucleating agents, thereby increasing the overall crystallinity of PLA. [ABSTRACT FROM AUTHOR]

This study focused on the development of a novel biocomposite material formed by a thermoplastic biodegradable polyester, poly(butylene succinate-co-adipate) (PBSA), and a carbonaceous filler as biochar (BC) derived by the pyrolysis of woody biomass waste. Composites with various BC contents (5, 10, 15, and 20 wt.%) were obtained by melt extrusion and investigated in terms of their processability, thermal, rheological, and mechanical properties. In all the composites, BC lowered melt viscosity, behaving as a lubricant, and enhancing composite extrudability and injection moulding at high temperatures up to 20 wt.% of biochar. While the use of biochar did not significantly change composite thermal stability, it increased its stiffness (Young modulus). Differential scanning calorimeter (DSC) revealed the presence of a second crystal phase induced by the filler addition. Furthermore, results suggest that biochar may form a particle network that hinders polymer chain disentanglement, reducing polymer flexibility. A biochar content of 10 wt.% was selected as the best trade-off concentration to improve the composite processability and cost competitiveness without compromising excessively the tensile properties. The findings support the use of biochar as a sustainable renewable filler and pigment for PBSA. Biochar is a suitable candidate to replace more traditional carbon black pigments for the production of biodegradable and inexpensive innovative PBSA composites with potential fertilizing properties to be used in agricultural applications. [ABSTRACT FROM AUTHOR]

In this study, one high-performance hemicelluloses (HC)-based sprayable and biodegradable pesticide mulch film was developed. Firstly, HC was transesterified with vinyl acetate (VA) to improve its solubility and film-forming ability. Then abamectin (ABA) was encapsulated by β-cyclodextrin (β-CD) to endow mulch film persistent anti-pesticide activity. After that, sodium alginate (SA) and gelatin were added to develop the mechanical performances of the mulch film. As a result, the obtained mulch film showed good characteristics, with optimum mechanical strength, elongation at break, water vapor permeability (WVP), swelling ratio (SR), and weight loss (biodegradability) of 7.9 ± 0.3 MPa, 43.6 ± 2.0 %, 2.1 ± 0.1 × 10−11 g mm m−2 s−1 kPa−1, 73.8 ± 2.0 %, and 69.3 %, respectively. After covering with mulch film, the soil moisture and temperature were developed to 90.8 % and 19.3 ± 0.2 °C, respectively, which could facilitate Chinese cabbage growth, with optimum germination rate of 98.6 ± 6.4 %. [Display omitted] • Hemicelluloses-based sprayable pesticide mulch films were successfully developed. • Abamectin-loaded β-CDs were incorporated to give films sustained anti-insect ability. • The films had good water retention ability, mechanical strength and biodegradability. • The films improved the soil temperature and moisture, facilitating cabbage growth. [ABSTRACT FROM AUTHOR]

An ever‐increasing rise in demand for sustainable materials has received significant attention in developing biocomposites for structural applications. In this regard, natural fibers replacing synthetic fibers as reinforcement in epoxy composite could be a significant gain toward sustainability, especially in automobile and structural applications. Herein, flax fiber/cellulose paper–reinforced epoxy biocomposite (FREC‐X) was fabricated via a vacuum infusion process. The influence of postcuring conditions (time and temperature) and cellulose paper density on the mechanical properties of FREC‐X was studied. The tensile strength and modulus of FREC‐X increased by 37% and 64%, respectively, upon the integration of paper. Postcuring FREC‐X further augmented the tensile and flexural properties of the composite, which could be attributed to the increase in cross‐linking of the epoxy and yields a strong polymer network. Fractography analysis confirmed that the composites integrated with paper showed fewer defects with improved interfacial adhesion. In addition, the water absorption and thickness swelling results revealed that the presence of cellulose paper marginally increased the water uptake and thickness swelling of FREC‐X. Furthermore, there was no significant change in the tensile and flexural properties of FREC‐X observed even after immersing in water for >200 h. Such properties of FREC‐X seen as a fascinating alternative to synthetic fibers and petroleum‐based epoxy and are promising material for sustainable development. [ABSTRACT FROM AUTHOR]

The present work highlights the preparation of the epoxidized natural rubber conjugated spent coffee biocomposites (ENR‐g‐SC) via one‐pot synthesis to control petroleum oil spills. The structural determination of the spent coffee grafted epoxidized natural rubber (ENR‐g‐SC) was confirmed through FTIR and 1H‐NMR spectroscopic analyses. The thermal performance, tensile tests, and morphological properties of the synthesized (ENR‐g‐SC) biocomposites were performed. The data revealed that ENR‐g‐SC biocomposite with 20 phr of spent coffee (SC) exhibited the highest tensile properties due to maximal chemical linkages of spent coffee and epoxide groups in ENR. The epoxidized natural rubber conjugated spent coffee copolymers were evaluated as oil sorbers for oil absorbency applications in chloroform, toluene, and 10% crude petroleum diluted with toluene. The data revealed that the oil absorbency increased slightly with chloroform or toluene instead of 10% crude oil diluted with toluene. Furthermore, swelling and network parameters including the maximum oil absorbency (Qmax), swelling rate constant (k), polymer‐solvent interaction (χ), effective crosslink density (ύe), equilibrium modulus of elasticity (GT), and average molecular weight between crosslinks (Mc) and theoretical crosslink density (ύt) were determined, and correlated to the efficiency of the synthesized epoxidized natural rubber conjugated spent coffee. [ABSTRACT FROM AUTHOR]

The usage of new cellulosic fibers in industrial applications is massive because of its excellent performances. These fibers are utilized especially for manufacture of high-performance composites. Coconut leaf sheath (CLS) fibers are extracted for leaf sheath of coconut tree. The aim of this paper is to study the possibility of using a natural fiber CLS as an alternative for polymer composites. In the current study, the consequence of NaOH treatment on structural, thermal and morphological behavior of treated and untreated coconut leaf sheath (CLS) fiber in terms of single fiber tensile strength, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (×RD), ther)mogravimetric analysis (TGA) and differential scanning calorimeter (DSC) has been explored. From SEM analysis, it was identified globular lumps spread consistently over the fiber which could help the mechanical interlock with the resin. The outcomes from the experimentation exposed that the NaOH treatment has impacted in the eradication of amorphous hemicellulose and lignin contents from the CLS fiber surface and in turn resulted in excellent structural and thermal stability behaviour of fiber. The present work endorses the great potential of CLS fibers to be utilized for bio-reinforcement in order to fabricate lightweight composite structures, employed in automobile and structural applications. [ABSTRACT FROM AUTHOR]

This work highlights the exploitation of fibers from a promising plant, commonly called Diss, in polymer matrix reinforcement. In this context, various untreated and treated (with acetic acid, silane, NaOH, thermal) Diss fibers were used to reinforce a thermoplastic matrix, polypropylene (PP). The effect of fiber treatments was evaluated at a ratio of 10% (by mass) of fiber, using mechanical, microstructural and physical characterization. A fiber content optimization study was carried out after choosing the fiber treatment by varying the fiber content from 10% to 40%. The microstructure observations showed a multi-layer structure for the biocomposites studied. The particular morphology of Diss fibers, with the presence of thorns, seems to improve the mechanical adhesion between the two phases. For 10% fiber content composites, the incorporation of the different fibers in the PP matrix led to improvements in most mechanical properties. The biocomposite reinforced with NaOH treated fibers (NPP-10%) showed the best mechanical performance with an improvement of 30%, 22% and 9% in tensile modulus, bending modulus and bending stress, respectively. For the fiber content variation, the NPP was retained, and an enhancement in the tensile modulus was found when the fiber content was below 20%. [ABSTRACT FROM AUTHOR]

Polyethylene is a polymer that has good elasticity properties, while polypropylene is a polymer with a high tensile strength value. Thus, the combination of these two polymers is expected to increase the value of tensile strength and elasticity. A biocomposite consisting of a mixture of Polyethylene-Polypropylene and thermoplastic sago starch (TPSS) was successfully prepared using the mixing method in an internal mixer. TPSS is made by reacting starch and glycerol with a composition of 65:35 wt.%. Compatibility was made by reacting Polyethylene-Polypropylene: Maleic anhydrate: Benzoyl peroxide with a composition of 88:9:3 wt. %. The match concentration used was 10wt.% based on the TPSS weight. The concentration of the Polyethylene-Polypropylene mixture starts from 0.10,15,20,25,30 and 100wt.%. The characterizations carried out are mechanical properties analysis are tensile strength, elongation at break and elasticity, FTIR analysis, and thermal properties are TGA and DTA. According to the test results, the addition of a mixture of polyethylene and polypropylene can increase the tensile strength from 1.7292MPa (without a mixture of polyethylene and polypropylene) to 4.8334MPa and the elongation at break also increases from 0.23% to 1.72% at a concentration of 30wt.%. Meanwhile, Young's Modulus decreased from 740 to 281MPa at a concentration of 30 wt. %. [ABSTRACT FROM AUTHOR]

This paper focuses on the effect of okra bast fillers on biodegradation of poly(vinyl alcohol) composites. Fibers were obtained from okra plant stems via biological degumming and subjected to different chemical treatments such as scouring, alkalizing, maleic anhydride treatment, and vinyl acetate grafting. The fibers were ground and PVA-okra bast filler composites were produced at 20 wt% fiber load via the solution casting method. The obtained composites were tested in terms of mechanical properties and exposed to biodegradation in soil. Effects of okra bast filler addition and chemical treatments on changes in mass, breaking strength, elasticity modulus, and breaking elongation of composites upon soil biodegradation were determined. The composites can be considered for utilization in packaging and agricultural applications. [ABSTRACT FROM AUTHOR]

A new class of biobased composites with tailorable mechanical properties made of natural fibers, polylactic acid, and ferulic acid derivatives (FAD) is studied. FAD was used to develop composites with elastomeric properties like improved elongation at break and highly reversible deformation upon elongation. Composites were prepared using raw and enzymatically treated hemp fibers. The fibers were defibrillated due to the enzymatic treatment increasing their aspect ratio. The composites were characterized by their mechanical properties and their reaction to fire. No significant change in the dispersion of the fibers in the composites was reported. Homogenously dispersed crystallites of FAD were observed by scanning electron microscopy in the PLA matrix and at the interface between the PLA and the fibers, where they are suspected to increase the free volume in correlation with a decrease in mechanical properties following the increase in the aspect ratio of the fibers. FAD also degraded the reaction to fire of the material with an increase in 10% of the peak of Heat Release Rate (pHRR) in comparison to neat PLA. It also increased the charring residue up to 3 wt.%. A synergistic effect between FAD and the lignin increasing the charring residue is also reported. [ABSTRACT FROM AUTHOR]

In this paper, a flexible and compact multiband wearable antenna with a simple and low-profile structure is proposed and investigated. It is able to operate over the frequency ranges from 0.824 GHz to 0.975 GHz and from 1.90 to GHz to 6 GHz, covering the most of identified frequency bands for biomedical applications. Moreover, the antenna demonstrates robust on-body performance and provides a suitable balance between small antenna size, high on-body radiation efficiency (between 5% and 11% for operating frequency bands), and a low value of the maximum 10 g specific absorption rate (0.47 W/kg) on a homogeneous semisolid phantom. [ABSTRACT FROM AUTHOR]

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Combating pollution caused by nondegradable thermoplastics is a significant challenge keeping in view of their marginal cost, mechanical strength and ease of use for the production of esthetic products. Only low-cost/waste natural fiber-reinforced composites provide a ray of hope for replacing the aforementioned composites, but these composites have significant limitations, including low mechanical strength and excessive water penetration. Varying the weight percentages of waste vetiver fiber, soy-based composites are fabricated and characterized in this study. The highest tensile and flexural strengths of the vetiver–soy composite are found as 49.78 MPa and 51.4 MPa, respectively. The fabricated composite is moderately hydrophobic in nature, as per the contact angle and water absorption studies. Post-soil burial degradation studies like weight loss, Fourier transform infra-red spectroscopy, and optical micrography revealed that produced composite is totally biodegradable in nature. As a result, vetiver–soy composite will be a viable replacement for plastic and plastic-based items majorly in sectors like auto mobile industry and packaging sector. [ABSTRACT FROM AUTHOR]

Bamboo scrimber is a sustainable engineered material that overcomes natural round bamboo's various weaknesses. This study compared the bamboo scrimber's mechanical (strength, stiffness, and ductility) to timber. The results showed that scrimber's physical and mechanical properties are comparable, even superior, to wood, especially in compression. Scrimber has a higher density than timber. Its drier equilibrium moisture content indicates that scrimber is more hydrophobic than timbers. The maximum crushing strength (σc//), compressive stress perpendicular-to-fiber at the proportional limit (σcp⊥) and that at the 0.04" deformation (σc0.04⊥), shear strength (τ//), longitudinal compressive modulus of elasticity (Ec//), lateral compressive modulus of elasticity (Ec⊥), and modulus of rigidity (G) of scrimber are higher than those of timbers. Both scrimber's and timber's flexural properties (modulus of rupture (σb) and flexural modulus of elasticity (Eb)) are comparable. On the contrary, the tensile strength parallel-to-fiber (σt//) of scrimber is weaker than that of timber. Scrimber is high ductility (μ > 6) when subjected to compression perpendicular-to-fiber, medium ductility (4 < μ ≤ 6) when subjected to compression parallel-to-fiber, and low ductility (brittle) when subjected to bending, shear, or tensile parallel-to-fiber. The higher ductility of scrimber may give an alarm and more time before failure than timbers. Timbers have brittle to lower ductility when receiving each kind of loading scheme. The ratio of shear modulus to strength (G/τ) and compression modulus to strength parallel-to-fiber (EC∥/σC∥) strongly correlates with the ductility ratio. However, the ratio of the flexural modulus of elasticity to the modulus of rupture (Eb/σb) and the ratio of the modulus Young to compression stress perpendicular-to-fiber (Ec⊥/σcp⊥) do not strongly correlate to the ductility value. [ABSTRACT FROM AUTHOR]

Cellulose-Sn(IV) (CSn) biocomposite was synthesized by cellulose and stannic chloride in ethanol medium using microwave irradiation for 2 min with 30 s of intermittent time intervals. The incorporation of Sn(IV) into the cellulose matrix was confirmed through FT-IR, XRD, TGA, SEM- EDS, and BET. The prepared composite CSn has been used for the adsorptive removal of As(III) from water. Parameters, such as initial concentration, adsorbent dose, initial As(III) concentration, and time required for the adsorption process, were optimized through the batch-adsorption process. The adsorption capacity of the CSn for As(III) adsorption was found to be 16.64 mg/g at pH 7.0. Freundlich isotherm was found to be more suitable for the adsorption process based on regression coefficient values. Pseudo-second-order kinetic model was found to be more suitable for understanding the kinetics of the adsorption of As(III). Weber–Morris model with non-zero intercept revealed that the mechanism of adsorption was not limited to the diffusion process only. The adsorption process was spontaneous and exothermic and showed a decrease in randomness. Chloride ions decreased the percentage removal of As(III) when the concentration of chloride ions was ten times that of As(III) concentration according to the results obtained through the effect of co-anions study. In this study, 5% (w/v) NaCl solution has been used for the regeneration of the material, and during up to five adsorption–desorption cycles, there was a gradual decrease in percentage removal of As(III) from 95% to 78% only, which proves the greener aspect of the CSn. The breakthrough volume of 1.25 L of 10 mg/L of As(III) in column studies revealed that the CSn could be applicable for larger sample volumes also. [ABSTRACT FROM AUTHOR]

The impact of polymeric materials on the environment is a growing concern and an incentive for their commercial appeal. In composites, the trend is to replace matrices of synthetic polymers (SPs) with biopolymers (BPs) to develop bio‐based composites. The increasing demand for such materials has driven their research and application in many industrial sectors, often accompanied by increasingly restrictive fire safety regulations. With the aim of decreasing the flammability of composites, various approaches have been pursued, in particular the use of flame‐retardant (FR) additives. However, at high FR loads, the mechanical properties can be compromised. This article briefly overviews some aspects of the fire behavior and mechanical properties of BPs and bio‐based composites. Using a chart‐based framework and quadrant‐based quantitative analysis, the fire and mechanical properties of flame‐retarded composite formulations are evaluated simultaneously, aimed at comparing the effects of BPs and SPs in flame‐retarded polymeric composites in relation with other variables. [ABSTRACT FROM AUTHOR]

This study investigates eco-friendly membrane biocomposites derived from biomass, utilizing cellulose microfibrils (CMF) as the main membrane material. Cellulose nanocrystals (CNC), isolated from rice husk, were added as reinforcing fillers in CMF flat sheet membranes. CNC with concentrations of 0%, 10%, 20%, and 30% were employed. Scanning electron microscopy images revealed that CNC influenced the surface profile and the pore structure of the membranes, reducing the porosity by 23%. The empty areas formed by CMF interaction were effectively filled by CNC. This modified membrane resulted in an increase in NaCl rejection of up to 16%. Dynamic water contact angle demonstrated the role of CNC in enhancing permeability, with a shorter spreading time of 13 min. It was also confirmed by the highest flux of 351 L/m − 2h−1 under pure water flux conditions. Mechanical properties were significantly improved, with a 125% increase in tensile strength and a modulus of 329 MPa. The distribution of CNC within the membranes filled pores and enhanced CMF interaction, facilitated by abundant hydroxyl groups in CNC. Overall, this study highlights the potential of eco-friendly membrane biocomposites derived from biomass, offering valuable insights for the development of sustainable and efficient membrane materials.

3D-printing or Additive Manufacturing (AM) has been growing as a rapid manufacturing process for many different applications, with Poly (Lactic Acid) as one of the most used materials for 3D-printing. PLA shows great promise for many applications to achieve the goals of the SDGs due to its biodegradability and biocompatibility but lacks when it comes to mechanical strength and thermal resistance. In this study, microcrystalline cellulose (MCC) fibers were introduced as a reinforcement to PLA. The biocomposite filaments were irradiated in a vacuum to enhance the crosslinking. Gamma-ray irradiation in a vacuum has successfully shown signs of crosslinking by increasing the tensile strength and thermal stability of the biocomposite, indicating an enhancement for PLA/MCC for various applications. On the other hand, changes in thermal properties also indicated that irradiation may reduce the processability of the composite, so it is necessary to study the conditions under which the mechanical properties and processability are compatible.

This work highlights the exploitation of fibers from a promising plant, commonly called Diss, in polymer matrix reinforcement. In this context, various untreated and treated (with acetic acid, silane, NaOH, thermal) Diss fibers were used to reinforce a thermoplastic matrix, polypropylene (PP). The effect of fiber treatments was evaluated at a ratio of 10% (by mass) of fiber, using mechanical, microstructural and physical characterization. A fiber content optimization study was carried out after choosing the fiber treatment by varying the fiber content from 10% to 40%. The microstructure observations showed a multi-layer structure for the biocomposites studied. The particular morphology of Diss fibers, with the presence of thorns, seems to improve the mechanical adhesion between the two phases. For 10% fiber content composites, the incorporation of the different fibers in the PP matrix led to improvements in most mechanical properties. The biocomposite reinforced with NaOH treated fibers (NPP-10%) showed the best mechanical performance with an improvement of 30%, 22% and 9% in tensile modulus, bending modulus and bending stress, respectively. For the fiber content variation, the NPP was retained, and an enhancement in the tensile modulus was found when the fiber content was below 20%.

The usage of new cellulosic fibers in industrial applications is massive because of its excellent performances. These fibers are utilized especially for manufacture of high-performance composites. Coconut leaf sheath (CLS) fibers are extracted for leaf sheath of coconut tree. The aim of this paper is to study the possibility of using a natural fiber CLS as an alternative for polymer composites. In the current study, the consequence of NaOH treatment on structural, thermal and morphological behavior of treated and untreated coconut leaf sheath (CLS) fiber in terms of single fiber tensile strength, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (×RD), thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) has been explored. From SEM analysis, it was identified globular lumps spread consistently over the fiber which could help the mechanical interlock with the resin. The outcomes from the experimentation exposed that the NaOH treatment has impacted in the eradication of amorphous hemicellulose and lignin contents from the CLS fiber surface and in turn resulted in excellent structural and thermal stability behaviour of fiber. The present work endorses the great potential of CLS fibers to be utilized for bio-reinforcement in order to fabricate lightweight composite structures, employed in automobile and structural applications.

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.

Biodegradable polymers have recently become attractive and have been increasingly used as matrix materials to replace fossil plastics due to concerns about the environmental issue. However, their application areas are limited due to their high costs and natural properties. In this study, we fabricated ecofriendly and economical polybutylene adipate terephthalate (PBAT) composites loaded with various concentrations of wood flour (WF) to investigate the effects on the PBAT and WF interfaces as well as the physical properties of the WF/PBAT biocomposites. Then, WF was acetylated with acetic anhydride, and the effect of WF acetylation on the mechanical and thermal properties of the biocomposites were investigated. The results showed that the tensile strength, tensile modulus, flexural strength and flexural modulus increased with WF loading in the composites, and acetylation could not only further increase these properties, but also increase the impact strength and elongation at break. The incorporation of WF would weaken the thermal stability of PBAT, but the thermal stability of the biocomposite could be improved after WF acetylation. The cold crystallization temperature and hydrophobicity of the WF/PBAT samples would be increased with the increasing load of the WF, while the melting enthalpy and the crystallinity of the samples reduced gradually. A morphological analysis of the modified composites revealed that the matrix exhibited greater interfacial interactions with the WF compared to the WF/PBAT. Considering the much lower cost of WF compared to PBAT, the improved properties of WF/PBAT biocomposites will make it economically competitive with other commercial polymers, and these biocomposites should have much wider application areas.

Disposable surgical gowns are usually made from petroleum-based synthetic fibers that do not naturally decompose, impacting the environment. A promising approach to diminish the environmental impact of disposable gowns involves utilizing natural fibers and/or bio-based synthetic fibers. In this study, composite webs from polylactic acid (PLA) bicomponent fiber and natural fibers, cattail and kapok fibers, were prepared using the hot press method. Only the sheath region of the PLA bicomponent fiber melted, acting as an adhesive that enhanced the strength and reduced the thickness of the composite web compared with its state before hot pressing. The mechanical and physical properties of these composite webs were evaluated. Composite webs created from kapok fibers displayed a creamy yellowish-white color, while those made from cattail fibers showed a light yellowish-brown color. Additionally, the addition of natural fibers endowed the composite webs with hydrophobic properties. The maximum natural fiber content, at a ratio of 30:70 (natural fiber to PLA fiber), can be incorporated while maintaining proper water vapor permeability and mechanical properties. This nonwoven material presents an alternative with the potential to replace petroleum-based surgical gowns.

This paper presents a novel cheminformatics approach for the design and synthesis of hydroxyapatite/collagen nanocomposites, which have potential biomedical applications in tissue engineering, drug delivery, and orthopedic and dental implants. The nanocomposites are synthesized by the co-precipitation method with different ratios of hydroxyapatite and collagen. Their mechanical, biological, and degradation properties are analyzed using various experimental and computational techniques. Attenuated total reflection–Fourier-transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction unveil the low crystallinity and nanoscale particle size of hydroxyapatite (22.62 nm) and hydroxyapatite/collagen composites (14.81 nm). These findings are substantiated by scanning electron microscopy with energy-dispersive X-ray spectroscopy, confirming the Ca/P ratio between 1.65 and 1.53 and attesting to the formation of non-stoichiometric apatites in all samples, further validated by molecular simulation. The antimicrobial activity of the nanocomposites is evaluated in vitro against several bacterial and fungal strains, demonstrating their medical potential. Additionally, in silico analyses are performed to predict the absorption, distribution, metabolism, and excretion properties and the bioavailability of the collagen samples. This study paves the way for the development of novel biomaterials using chemoinformatics tools and methods, facilitating the optimization of design and synthesis parameters, as well as the prediction of biological outcomes. Future research directions should encompass the investigation of in vivo biocompatibility and bioactivity of the nanocomposites, while exploring further applications and functionalities of these innovative materials.

Biomass–fungi biocomposite materials are derived from sustainable sources and can biodegrade at the end of their service. They can be used to manufacture products that are traditionally made from petroleum-based plastics. There are potential applications for these products in the packaging, furniture, and construction industries. In the biomass–fungi biocomposite materials, the biomass particles (made from agricultural waste such as hemp hurd) act as the substrate, and a network of fungal hyphae grow through and bind the biomass particles together. Typically, molding-based methods are used to manufacture products using these biocomposite materials. Recently, the authors reported a novel extrusion-based 3D printing method using these biocomposite materials. This paper reports a follow-up investigation into the effects of mixing parameters (mixing time and mixing mode) on fungal growth in biomass–fungi mixtures prepared for 3D printing and the effects of printing parameters (printing speed and extrusion pressure) on fungal growth in printed samples. The fungal growth was quantified using the number of fungal colonies that grew from samples. The results show that, when mixing time increased from 15 to 120 s, there was a 52% increase in fungal growth. Changing from continuous to intermittent mixing mode resulted in an 11% increase in fungal growth. Compared to mixtures that were not subjected to printing, samples printed with a high printing speed and high extrusion pressure had a 14.6% reduction in fungal growth, while those with a low printing speed and low extrusion pressure resulted in a 16.5% reduction in fungal growth.

This study investigates the mechanical properties of α-chitin and chitosan biocomposites using molecular dynamics (MD) and stress–strain analyses under uniaxial tensile loading in an aqueous environment. Our models, validated against experimental data, show that α-chitin has a higher directional elastic modulus of 51.76 GPa in the x and 39.76 GPa in the y directions compared to its chitosan biocomposite, with 31.66 GPa and 26.00 GPa in the same directions, demonstrating distinct mechanical behaviors between α-chitin and the biocomposite. The greater mechanical stiffness of α-chitin can be attributed to its highly crystalline molecular structure, offering potential advantages for applications requiring load-bearing capabilities. These findings offer valuable insights for optimizing these materials for specialized applications.

The presented study is focused on the modification of commercially available epoxy resin with flame retardants by means of using natural substances, including quercetin hydrate and potato starch. The main aim was to obtain environmentally friendly material dedicated to rail transport that is resistant to the aging process during exploitation but also more prone to biodegradation in environmental conditions after usage. Starch is a natural biopolymer that can be applied as a pro-ecological filler, which may contribute to degradation in environmental conditions, while quercetin hydrate is able to prevent a composite from premature degradation during exploitation. To determine the aging resistance of the prepared materials, the measurements of hardness, color, mechanical properties and surface free energy were performed before and after solar aging. To assess the mechanical properties of the composite material, one-directional tensile tests were performed for three directions (0, 90, 45 degrees referred to the plate edges). Moreover, the FT-IR spectra of pristine and aged materials were obtained to observe the changes in chemical structure. Furthermore, thermogravimetric analysis was conducted to achieve information about the impact of natural substances on the thermal resistance of the achieved composites.

This paper presents the results of a study investigating the biodegradation of poly(butylene succinate) (PBS)/wheat bran (WB) biocomposites. Injection mouldings were subjected to biodegradation in compost-filled bioreactors under controlled humidity and temperature conditions. The effects of composting time (14, 42 and 70 days) and WB mass content (10%, 30% and 50% wt.) on the structural and thermal properties of the samples were investigated. Measurements were made by infrared spectral analysis, scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and gel permeation chromatography. Results demonstrated that both the thermal and structural properties of the samples depended greatly on the biodegradation time. Specifically, their crystallinity degree increased significantly while molecular mass sharply decreased with biodegradation time, whereas their thermal resistance only showed a slight increase. This resulted from enzymatic hydrolysis that led to the breakdown of ester bonds in polymer chains. It was also found that a higher WB content led to a higher mass loss in the biocomposite samples during biodegradation and affected their post-biodegradation properties. A higher bran content increased the degree of crystallinity of the biocomposite samples but reduced their thermal resistance and molecular mass.

Biocomposites based on polylactic acid (PLA), tall wheatgrass (TWG), and hemp (H) were made by injection molding. The article discusses the impact of the agrofiller content on the composite properties, including thermal (DSC, DMA, and TG) and mechanical characteristics (tensile modulus, tensile strength, and impact strength). Generally, the introduction of a plant filler into the polylactide matrix reduced the thermal resistance of the resulting composites. Plant fillers influenced primarily the cold crystallization process, probably due to their nucleating properties. The addition of fillers to the PLA matrix resulted in an increased storage modulus across all tested temperatures compared to pure PLA. In the case of a composite with 50% of plant fillers, it was almost 118%. The mechanical properties of the tested composites depended significantly on the amount of plant filler used. It was observed that adding 50% of plant filler to PLA led to a twofold increase in tensile modulus and a decrease in tensile strength and impact strength by an average of 23 and 70%, respectively. It was determined that composites incorporating tall wheatgrass (TWG) particles exhibited a slightly elevated tensile modulus while showcasing a marginally reduced strength and impact resistance in comparison to composites containing hemp (H) components.

In this study, we utilized a hybridization approach for two different fibers to overcome the drawbacks of single-fiber-reinforced PLA composites. Coir fiber and bamboo leaf fiber were used as reinforcing natural fibers as their properties complement one another. Additionally, we combined thermal annealing with hybridization techniques to further improve the overall properties of the composites. The results showed that the hybridization of BF: CF with a ratio of 1:2 gave PLA-based hybrid composites optimal mechanical and thermal properties. Furthermore, the improvement in the thermal stability of hybrid composites, attributable to an increase in crystallinity, was a result of thermal annealing. The improvement in HDT in annealed 1BF:2CF hybrid composite was about 13.76% higher than that of the neat PLA. Annealing of the composites led to increased crystallinity, which was confirmed using differential scanning calorimetry (DSC). The synergistic effect of hybridization and annealing, leading to the improvement in the thermal properties, opened up the possibilities for the use of PLA-based composites. In this study, we demonstrated that a combined technique can be utilized as a strategy for improving the properties of 100% biocomposites and help overcome some limitations of the use of PLA in many applications.

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Measurement of mechanical properties of biocomposites is a good method for evaluating their effectiveness of adhesion between fiber and polymer matrix. In this research, the effects of four different chemical treatments of flax fiber on some mechanical properties of their biocomposites was investigated. Initially, the flax fiber was soaked in alkaline, silane, benzoyle and peroxide solution and the fiber were dried in an air-cabinet drier at 70°C. After grinding, each group were separately mixed with HDPE powder at a ratio of 10% flax fiber and 90% HDPE. From these mixture, composite plates were prepared through extruding, pelleting, and rotational molding. The resulting composites were tested for their various mechanical properties using tensile tests. The test results indicated the maximum strain was 6.22%, maximum supported load at yield point was 582 N, maximum stress at yield pint was 20.26 MPa and maximum modulus of elasticity was 467.75 MPa all for alkaline treatment. It was found that all tested mechanical properties for HDPE were significantly lower than the composites made from fiber containing biocomposites. However there was no significant difference between the mechanical strength of composites produced from various chemical treatments.

Silkworm cocoon is a natural biological and composite structure that has evolved over time and has high physical and mechanical properties against stress and acts as insulation against ambient temperature conditions. Understanding the relationships between the two-component structure of silkworm cocoons (sericin and fibroin) inspires the creation of composite structures, including lightweight, high-strength nonwoven biocomposites. In the present study, by analytical-descriptive method, we have tried to use cocoon sericin and introduce some famous and widely used natural fibers in materials science and study their characteristics - because for various reasons such as lightness, lack of pollution and low cost, etc. can be suitable alternative for a replacement of synthetic fibers - suggest the production of non-woven bio-composite materials. Natural fibers such as jute, hemp, flax, etc. with different volume percentages in combination with sericin as a binder, were proposed for this biocomposite and the thermal performance of each of them was compared using Maxwell's theoretical model. All compounds show low thermal conductivity and jute-sericin biocomposite with 70% by volume and 0.061 W/m2-K performance has better performance.

Viscose rayon filaments were used as reinforcement in the chitosan matrix (dissolved in acetic acid) to create a truly green composite. Unidirectional composites with different weights of viscose rayon filament were fabricated. The composite material was characterized by tensile strength, FTIR, TGA, XRD, and SEM. The tensile strength of the biocomposite increased (43.81%), and elongation % decreased (11.42%) with an increase in reinforcement loading. FTIR spectra of biocomposites confirmed strong hydrogen bonding between chitosan and hydroxyl groups of viscose rayon. The SEM micrograph indicated that the viscose rayon filament was fully surrounded by the matrix, and hence a strong composite was fabricated.

Abstract Purpose Biodegradable interference screws (IFS) can be manufactured from different biomaterials. Magnesium was previously shown to possess osteoinductive properties, making it a promising material to promote graft‐bone healing in anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to compare IFS made from magnesium to a contemporary biocomposite IFS. Methods In a porcine model of ACL reconstruction, deep porcine flexor tendons were trimmed to a diameter of 8 mm, sutured in Krackow technique, and fixed with either 8 × 30 mm biocomposite IFS (Bc‐IFS) or 8 × 30 mm magnesium IFS (Mg‐IFS) in an 8 mm diameter bone tunnel in porcine tibiae. Cyclic loading for 1000 cycles from 0 to 250 N was applied, followed by load to failure testing. Elongation, load to failure and stiffness of the tested constructs was determined. Results After 1000 cycles at 250 N, elongation was 4.8 mm ± 1.5 in the Bc‐IFS group, and 4.9 mm ± 1.5 in the Mg‐IFS group. Load to failure was 649.5 N ± 174.3 in the Bc‐IFS group, and 683.8 N ± 116.5 in the Mg‐IFS group. Stiffness was 125.3 N/mm ± 21.9 in the Bc‐IFS group, and 122.5 N/mm ± 20.3 in the Mg‐IFS group. No significant differences regarding elongation, load to failure and stiffness between Bc‐IFS and Mg‐IFS were observed. Conclusion Magnesium IFS show comparable biomechanical primary stability in comparison to biocomposite IFS and may therefore be an alternative to contemporary biodegradable IFS.

ABSTRACTA new class of biobased composites with tailorable mechanical properties made of natural fibers, polylactic acid, and ferulic acid derivatives (FAD) is studied. FAD was used to develop composites with elastomeric properties like improved elongation at break and highly reversible deformation upon elongation. Composites were prepared using raw and enzymatically treated hemp fibers. The fibers were defibrillated due to the enzymatic treatment increasing their aspect ratio. The composites were characterized by their mechanical properties and their reaction to fire. No significant change in the dispersion of the fibers in the composites was reported. Homogenously dispersed crystallites of FAD were observed by scanning electron microscopy in the PLA matrix and at the interface between the PLA and the fibers, where they are suspected to increase the free volume in correlation with a decrease in mechanical properties following the increase in the aspect ratio of the fibers. FAD also degraded the reaction to fire of the material with an increase in 10% of the peak of Heat Release Rate (pHRR) in comparison to neat PLA. It also increased the charring residue up to 3 wt.%. A synergistic effect between FAD and the lignin increasing the charring residue is also reported.

Alginate based biofilms are widely used for designing edible food packaging while its application for developing inedible waterproof food packaging has not been studied enough. Both, cellulose fiber and alginate are attractive natural materials that could be used for developing natural fiber-based food packaging. In this research the cellulose/alginate biocomposites were produced by eco-friendly technique bi-layer lamination of prepared cellulose (C) fiber plates with sodium (SA) and calcium alginates (CA) containing glycerol as plasticizer. The morphology, moisture content, solubility in water, water vapor permeability (WVP), surface hydrophobicity and mechanical characteristics of prepared cellulose/alginates biocomposites were evaluated and compared. The biocomposite surface morphology evaluation showed that all analyzed samples had smooth surfaces without cracks. Moreover, obtained results showed that plasticizer is essential in developing biocomposites with improved characteristics. The concentration of glycerol had a positive effect on gloss, flexibility, moisture content, solubility in water and negative effect to surface hydrophobicity of C/SA and C/CA biocomposites. It was observed that samples had partly hydrophobic surfaces which contact angles varies from 37° to 63°. Mechanical characteristics revealed that the most promising are C/CA biocomposites that could be further modified for waterproof food packaging developing. [ABSTRACT FROM AUTHOR]

The present study focuses on the development of biodegradable composites to replace synthetic polymer-based composites for potential lightweight structural applications in the automobile, aeronautical, marine, and packaging industries. Initially, PLA and NFBF/PLA films are prepared by solution casting, and from these films, composite laminates are prepared by film sequencing and compression (hot-press) molding methods. First, the critical buckling load (Pcr) of composites is analyzed, and then, the influence of compressive load on natural frequency is studied. The critical buckling load-bearing capacity of PLA is enhanced with the reinforcement of NFBF (natural fiber braided yarn fabric). The composite with three layers of NFBF registered the highest critical-buckling load (Pcr) of 374.19 N, and this value is 172.13% high compared to the virgin PLA. Similarly, the natural frequency of the NFBF composites approaches minimum when the applied load is equal to the corresponding Pcr. However, a significant increase in the fundamental frequency is noticed when the applied load is higher than the Pcr. [ABSTRACT FROM AUTHOR]

In recent decades, scientists have started to search for more sustainable and environmentally friendly materials. It is known that building materials are among the most used materials and have a visible negative effect on the environment. The development of environmentally friendly composites in buildings offers different solutions to decrease energy consumption. The aim of the present study is to investigate a new biocomposite material fabricated with natural date palm fibers (DPFs), cement, and sand. The main objective is to assess the thermal insulation characteristics as well as the water absorption and mechanical performance of this material for building industry. The percentage by weight of DPF in the studied specimens ranged from 0% to 30% for two fiber sizes. The characteristics of these specimens were determined experimentally in terms of flexural and compression strength as well as thermal conductivity. The results confirmed that the thermal conductivity decreases with the addition of DPF. Also, the compressive strength of the composite decreases with the weight reduction. Thus, DPF has a positive effect on the thermo-mechanical properties of the considered material. Consequently, it considerably improves the mortar insulating capacity. [ABSTRACT FROM AUTHOR]

However, for the first time in literature, we have fabricated a biocomposite from glasswort (GW) as a natural fiber in high-density polyethylene (HDPE) matrix and investigated the interaction of GW with a commodity plastic by examining the mechanical and surface properties of composites. SEM micrographs of (a) GW fiber powder at 100x, (b) GW fiber powder at 500x, (c) 15 wt% GW filled HDPE at 100x, (d) 15 wt% GW filled HDPE at 250x magnifications As observed in Figure 9a and 9b, some of the splinter structures which have a radius that can pass through the filter neck, but larger than the longitudinal filter neck which can reach about 980 µm length but have 200 µm radius, were present. Gained mass percentages according to weeks HT

Synthesis and Properties of Full Bio-Based Thermosetting Resins from Rosin Acid and Soybean Oil: The Role of Rosin Acid Derivatives. Conclusion Chicken feather fiber based composites were prepared successfully using MAESO resin, chicken feather fiber as reinforcing agent and rosin acid derivatives as crosslinker. FT-IR Study of Rosin and its Derivatives Figure 2 shows the FT-IR spectra of rosin acid and its derivatives. By considering the above points, the present work reports the preparation of composites with rosin acid derivative as rigid monomers which will co-polymerize with modified ESO to form fully bio-based resin and its role in property enhancement of CFF based polymer composites. [Extracted from the article]

Recent investigations proposed alternatives for utilization of Açaí (Euterpe oleracea Mart.) fruit wastes, seeds, and lignocellulosic fibers. However, Açaí leaves may also be obtained without harvesting the palms and could be used in higher value-added products. Alkali reaction (1% and 5% of NaOH), different temperatures (70°C, 80°C, and 100°C), and bleaching were combined to produce fibres from the Açaí leaves. Scanning electron microscopy, X-ray diffraction, and thermogravimetry were used to evaluate the effect of treatments on fibers, whereas X-ray diffraction and calorimetry were employed to characterize Portland cement pastes containing fibers. Results indicated that Açaí leaves could be transformed into short-length fibers with improved degrading temperature. Alkali treatment at 5% sodium hydroxide (90°C) and bleaching increased fibers' crystallinity and showed efficiency in removing non-cellulosic components. Cement paste evaluation also indicated that fibers treated at 5% NaOH solution caused fewer changes in calorimetric profile and therefore present a greater potential for cement-based composites. [ABSTRACT FROM AUTHOR]

A green biocomposite (BTF-i-ACS) consisting of banana trunk fibers (BTF)-infused acidified chitosan (ACS) was prepared. The biocomposite was characterized by means of Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The results of characterization indicated that BTF are widely immobilized in ACS without any chemical interaction. The biocomposite was used for the removal of Cd2+ from aqueous media. The effect of pH, contact time and initial concentration was evaluated. Contact time of 120 min and pH ~ 6.50 were selected for the removal of Cd2+ at ambient temperature (27 ± 1 °C). The percentage removal of Cd2+ was found to be 92.67%. The data best fitted pseudo-second order kinetics and Freundlich isotherm model indicating that the rate-limiting step might be chemisorption involving sharing or transfer of electrons between Cd2+ and biocomposite. [ABSTRACT FROM AUTHOR]

The aim of this study was to obtain biocomposites consisting of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), bacterial cellulose (BC) and α-tocopherol by a melt processing technique for potential use in biomedical applications. The melt processing and roughness of biocomposites were evaluated and compared to sample without BC. The degradation rate of PHBV/BC biocomposites was measured in phosphate buffer saline (PBS) by determining the mass variation and evidencing of thermal and structural changes by differential scanning calorimetry (DSC) and attenuated total reflectance-Fourier transformed infrared spectrometry (ATR-FTIR). The cell viability, cell morphology, cell cycle distribution and total collagen content were investigated on murine NCTC fibroblasts. Overall, the adding of BC to polyester matrix led to an adequate melt processing of biocomposites and increased surface roughness and cytocompatibility, allowing the cells to secrete the extracellular matrix (collagen) and stimulate cell proliferation. Results showed that the PHBV/BC biocomposites were favorable for long-term degradation and could be used for the design of medical devices with controlled degradability. [ABSTRACT FROM AUTHOR]

In this study, leather-like composites were prepared from natural rubber (NR) and two different types of leather waste, namely wet blue leather (WBL) and finished leather (FL). Compounding was carried out on an internal mixer and two-roll mill, and curing was further conducted on a compression molding machine. The effects of leather type and content from 20 to 80 parts per hundred of rubber (phr) on cure characteristics, mechanical properties (hardness and tensile properties) and thermal stability of the as-prepared composites were investigated and compared with those of the unfilled NR compound. The curing rate and crosslink density of all composites were found to be lower than those of the unfilled NR. All WBL-filled NR composites exhibited higher tensile strength than the unfilled NR, while all FL-filled NR composites had lower values. Meanwhile, the hardness and modulus at 200% strain of all composites were increased with increasing leather waste contents compared to those of the unfilled NR. The composites containing low WBL loadings (20 and 40 phr) demonstrated higher elongation at break over the unfilled NR, while the other composites exhibited lower values. Besides, the thermal stability of all NR composites was deteriorated, but still largely retained. [ABSTRACT FROM AUTHOR]