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Cellulosic fibers obtained from Barley straw were utilized to reinforce PHB. Four different processed fibers were employed as reinforcing material: sawdust (SW), defibered (DFBF), delignified (DBF), and bleached (BBF) fibers. The composite was processed from two different perspectives: a discontinuous (bach) and an intensification process (extrusion). Once processed and transformed into final shape specimens, the materials were characterized by mechanical testing (tensile mode), scanning electron microscopy, and theoretical simulations by finite elements analysis (FEA). In terms of mechanical properties, only the elastic moduli (Et) exhibited results ranging from 37% to 170%, depending on the reinforcement composition. Conversely, strengths at break, under both tensile and bending tests, tended to decrease, indicating poor affinity between the components. Due to the mechanical treatment applied on the fiber, DFBF emerged as the most promising filler, with mechanical properties closest to those of neat PHB. DFBF-based composites were subsequently produced through process intensification using a twin-screw extruder, and molded into flowerpots. Mechanical results showed almost identical properties between the discontinuous and intensification processes. The suitability of the material for agriculture flowerpots was demonstrated through finite analysis simulation (FEA), which revealed that the maximum von Mises stresses (5.38 × 105 N/m2) and deformations (0.048 mm) were well below the limits of the composite materials. [ABSTRACT FROM AUTHOR]

The use of wheat middlings (WM) and rice husks (RH) as biofillers for mixing with poly(lactic acid) (PLA) matrix to produce new 3D-printable biocomposites was assessed. Filaments containing 10 and 20 wt.% agro-waste-derived biofillers were manufactured and, for the sake of comparison, filaments of neat PLA were also produced. The obtained filaments were characterized via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), showing potential for further application in additive manufacturing processing. Three-dimensionally printed specimens were thus produced and characterized via: DSC, also evaluating the specific heat capacity (CP) of specific 3D-printed specimens; dynamic mechanical analysis (DMA), also applied for determining the coefficient of linear thermal expansion (CLTE) measured on 3D-printed specimens in two different directions (X and Y); and tensile tests. The latter testing campaign was carried out along three printing directions (X, Y, and Z axes) to test the intrinsic biocomposite features (X-printed samples) as well as interbead and interlayer adhesion (Y- and Z-printed specimens, respectively). All samples demonstrated acceptable properties. The inclusion of a cost-free natural material leads to a strong reduction of the whole material cost. Implementing this new class of composite material to an additive manufacturing technique can significantly reduce the environmental impact of 3D-printed products. [ABSTRACT FROM AUTHOR]

The low carbon footprint, biodegradability, interesting mechanical properties, and relatively low price are considered some of the reasons for the increased interest in polylactic acid-based (PLA-based) filaments supplied with natural fillers. However, it is essential to recognize that incorporating natural fillers into virgin PLA significantly impacts the printability of the resulting blends. The complex inter-relationship between process, structure, and properties in the context of fused deposition modeling (FDM)-manufactured biocomposites is still not fully understood, which thus often results in decreased reliability of this technology in the context of biocomposites, decreased accuracy, and the increased presence of defects in the manufactured biocomposite samples. In light of these considerations, this study aims to identify the optimal processing parameters for the FDM manufacturing process involving wood-filled PLA biocomposites. This study presents an optimization approach consisting of Grey Relational Analysis in conjunction with the Taguchi orthogonal array. The optimization process has identified the combination of a scanning speed of 70 mm/s, a layer height of 0.1 mm, and a printing temperature of 220 °C as the most optimal, resulting in the highly satisfactory combination of good dimensional accuracy (Dx = 20.115 mm, Dy = 20.556 mm, and Dz = 20.220 mm) and low presence of voids (1.673%). The experimentally determined Grey Relational Grade of the specimen manufactured with the optimized set of process parameters (0.782) was in good agreement with the predicted value (0. 754), substantiating the validity of the optimization process. Additionally, the research compared the efficacy of optimization between the integrated multiparametric method and the conventional monoparametric strategy. The multiparametric method, which combines Grey Relational Analysis with the Taguchi orthogonal array, exhibited superior performance. Although the monoparametric optimization strategy yielded specimens with favorable values for the targeted properties, the analysis of the remaining characteristics uncovered unsatisfactory results. This highlights the potential drawbacks of relying on a singular optimization approach. [ABSTRACT FROM AUTHOR]

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biobased and biodegradable polymer. This polymer is considered promising, but it is also rather expensive. The objective of this study was to compound PHBV with three different organic fillers considered waste: human hair waste (HHW), sawdust (SD) and chitin from shrimp shells. Thus, the cost of the biopolymer is reduced, and, at the same time, waste materials are valorised into something useful. The composites prepared were characterised by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile strength and scanning electron micrograph (SEM). Tests showed that chitin and HHW did not have a reinforcing effect on tensile strength while the SD increased the tensile strength at break to a certain degree. The biodegradation of the different composites was evaluated by a soil burial test for five months. The gravimetric test showed that neat PHBV was moderately degraded (about 5% weight loss) while reinforcing the polymer with organic waste clearly improved the biodegradation. The strongest biodegradation was achieved when the biopolymer was compounded with HHW (35% weight loss). The strong biodegradation of HHW was further demonstrated by characterisation by Fourier-transform infrared spectroscopy (FTIR) and solid-state nuclear magnetic resonance (NMR). Characterisation by SEM showed that the surfaces of the biodegraded samples were eroded. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Wood–plastic composites (WPCs) represent composite materials that employ shredded wood combined with a thermoplastic substance, such as polylactic acid (PLA), to establish structural cohesion within the product profile. This amalgamation of materials results in a robust structure designed to fulfill specialized roles under the influence of pressure and temperature. Given the nature of the constituent materials, the resultant product can be classified as a biocomposite. The creation of such biocomposites entails a rigorous process necessitating the fine-tuning of specific parameters and suitable technologies. The foundational materials employed in this process must be both natural and biodegradable. However, it is noteworthy that natural components like fibers exhibit anisotropic behavior, wherein their mechanical attributes are contingent on the direction of the applied force. Consequently, predicting their performance during biocomposite production proves challenging. The principal objective of this study was to conduct a comparative analysis of wood-based composites incorporating PLA thermoplastic binding agents. The intention was to discern variations in density profiles arising from distinct measurement methodologies. Two measurement methods were used for the measurement: X-ray and spectrum desaturation. Additionally, the study sought to investigate the impact of introducing PLA additives at 25% and 50% concentrations on the fabrication of WPC from wood chips. The properties of these composites were assessed by considering the inherent traits of the composite materials. [ABSTRACT FROM AUTHOR]

Hydroxyapatite doped with magnesium and zinc in chitosan matrix biocomposites have great potential for applications in space technology, aerospace, as well as in the biomedical field, as a result of coatings with multifunctional properties that meet the increased requirements for wide applications. In this study, coatings on titanium substrates were developed using hydroxyapatite doped with magnesium and zinc ions in a chitosan matrix (MgZnHAp_Ch). Valuable information concerning the surface morphology and chemical composition of MgZnHAp_Ch composite layers were obtained from studies that performed scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), metallographic microscopy, and atomic force microscopy (AFM). The wettability of the novel coatings, based on magnesium and zinc-doped biocomposites in a chitosan matrix on a titanium substrate, was evaluated by performing water contact angle studies. Furthermore, the swelling properties, together with the coating's adherence to the titanium substrate, were also analyzed. The AFM results emphasized that the composite layers exhibited the surface topography of a uniform layer, and that there were no evident cracks and fissures present on the investigated surface. Moreover, antifungal studies concerning the MgZnHAp_Ch coatings were also carried out. The data obtained from quantitative antifungal assays highlight the strong inhibitory effects of MgZnHAp_Ch against C. albicans. Additionally, our results underline that after 72 h of exposure, the MgZnHAp_Ch coatings display fungicidal features. Thus, the obtained results suggest that the MgZnHAp_Ch coatings possess the requisite properties that make them suitable for use in the development of new coatings with enhanced antifungal features. [ABSTRACT FROM AUTHOR]

Extrusion and hot compressing molding processes were used to create bio-polyethylene (BioPE) composites reinforced with argan byproducts (shell, pulp, and argan cake) as bio-fillers. The thermal stability of the composites wass analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Dynamical mechanical analysis and rheological testing were used to investigate their mechanical properties. The morphological results showed a good adhesion between the argan and BioPE matrix. More efficient mechanical properties have been distinguished in the case of argan byproduct-based composite. A higher Young's modulus was noted for all the biocomposites compared to pure BioPE. Thermal analysis revealed that the addition of bio-filler to polymer reduced decomposition temperatures. This study provides an ecological alternative for upgrading the valorization of abundant and underutilized Moroccan biomass. Furthermore, the possibility of using argan byproducts in composite manufacturing will help open up new markets for what is currently considered waste. [ABSTRACT FROM AUTHOR]

When developing new innovative building materials, their performance characteristics as well as their environmental friendliness are important. It is difficult to produce a fully ecological material for building envelopes, because there is a lack of ecological binding materials on the market, good binding materials are very expensive, and cheaper ones have poorer adhesive properties and performance characteristics. In this work, natural organic sapropel was used as an ecological binder. Before use, an organic sapropel was additionally mechanically activated. Its activation efficiency was evaluated on the basis of consistency and tensile strength. Sapropel activation increased its consistency from 112 to 168 mm and its tensile strength from 466 to 958 kPa. Wood processing waste was used as a filler for the thermal insulation biocomposite. Additionally, the wood waste was chopped to regulate the density and main performance properties of the biocomposite. The density of the biocomposite was also regulated using different amounts of sapropel and the degree of compaction of the composite mixture. In this work, the influence of the amount of sapropel, the level of compression of the biocomposite mixture, and the size of the wood waste particles on the thermal conductivity and compressive stress of the biocomposite was analyzed. It was found that the compression level had the greatest influence on both the compressive stress and thermal conductivity, up to 12 times and 43.3%, respectively. [ABSTRACT FROM AUTHOR]

Biobased composites offer unique properties in the context of sustainable material production as well as end-of-life disposal, which places them as viable alternatives to fossil-fuel-based materials. However, the large-scale application of these materials in product design is hindered by their perceptual handicaps and understanding the mechanism of biobased composite perception, and its constituents could pave the way to creating commercially successful biobased composites. This study examines the role of bimodal (visual and tactile) sensory evaluation in the formation of biobased composite perception through the Semantic Differential method. It is observed that the biobased composites could be grouped into different clusters based on the dominance and interplay of various senses in perception forming. Attributes such as Natural, Beautiful, and Valuable are seen to correlate with each other positively and are influenced by both visual and tactile characteristics of the biobased composites. Attributes such as Complex, Interesting, and Unusual are also positively correlated but dominated by visual stimuli. The perceptual relationships and components of beauty, naturality, and value and their constituent attributes are identified, along with the visual and tactile characteristics that influence these assessments. Material design leveraging these biobased composite characteristics could lead to the creation of sustainable materials that would be more attractive to designers and consumers. [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]

The aim of the present research was the development of a management method for wood-processing waste that was obtained during the production of parquet flooring. Currently mostly useless, such waste mainly ends up in landfills. The oak waste flour was used as a reinforcement material for epoxy biocomposites based on the polyaddition product of epoxidized soybean oil and bisphenol-A (ESBO_BPA). The biofiller was subjected to mercerization, acetylation, and diisocyanate modification to increase the typically poor compatibility between the highly hydrophilic wood fibers and the hydrophobic polymer matrix. Among the analyzed epoxy biocomposites, which contained about 60% raw materials of natural origin, it was found that the best mechanical properties were recorded for cured samples of the ESBO_BPA composition filled with 5 wt % of oak flour mercerized using a 5% solution of NaOH. It was also proven that a higher concentration of alkali deteriorated the mechanical-strengthening properties of the wood filler. The acetylation of the biofiller independently in the best elimination of hydroxyl groups from its structure also removed irregular strips and smoothed its surface. This resulted in a poorer wettability of the oak flour surface by the polymer and consequently an easier pullout of the filler from the polymer matrix and worse mechanical properties of the wood/epoxy composite. To the best of the authors' knowledge, the present research was the first to examine the possibility of the application of parquet flooring post-production wood flour in biomaterials based on a polyaddition product of epoxidized soybean oil and bisphenol-A. [ABSTRACT FROM AUTHOR]

The fractionation of diatomaceous earth (DE) using sedimentation made it possible to obtain separate unbroken diatom fractions from broken or agglomerated bodies with a range of particle sizes. The produced filler was used to prepare polylactide (PLA)/diatomaceous earth biocomposite samples containing different particle sizes, which were subjected to mechanical testing (tensile strength, flexural strength, impact strength), colloidal testing (contact angle, color change test, SEM/EDS), and thermal testing (TGA, DSC, DMA). Modification of the PLA containing the smallest particle size with diatomaceous earth (Fraction 5) resulted in a higher impact strength compared to both the pure PLA and the PLA/DE composite that contained base diatomaceous earth. Furthermore, the melt flow rate was improved by more than 80 and 60% for the composite modified with fractionated diatomaceous earth (Fraction 4) compared to pure PLA and base diatomaceous earth, respectively. The elasticity of the composite was also improved from 3.3 GPa for pure polylactide to 4.4 GPa for the system containing the smallest diatomaceous earth particles (Fraction 5). [ABSTRACT FROM AUTHOR]

Nanoindentation is widely used to investigate the surface-mechanical properties of biocomposites. In this study, polypropylene random copolymer (PPRC) and biowaste rice husk (BRH) were used as the main raw materials, and glass-fiber-reinforced polypropylene and talc were also used with BRH to enhance the mechanical characterization of the biocomposites. The interfacial bonding between the polymer and the rice husk was increased by treating them with maleic anhydride and NaOH, respectively. The results obtained from the nanoindentation indicated that the plastic behavior of the biocomposites was prominent when untreated BRH was used and vice versa. The modulus and hardness of the biocomposite improved by 44.8% and 54.8% due to the neat PPRC, respectively. The tribological properties were studied based on the hardness-to-modulus ratio and it was found that BRH- and talc-based biocomposites were better than other samples in terms of low friction and wear rate. The creep measurements showed that untreated rice husk biocomposite exhibited high resistance to load deformation. [ABSTRACT FROM AUTHOR]

Among the various methods for collecting oil spills and oil products, including from the water surface, one of the most effective is the use of sorbents. In this work, three-component bio-based composite granular adsorbents were produced and studied for oil products' pollution collection. A bio-based binder made of peat, devulcanised crumb rubber from used tyres, and part fly ash as cenospheres were used for absorbent production. The structure, surface morphology, porosity, mechanical properties, and sorption kinetics of the obtained samples were studied. Composite hydrophobicity and sorption capacity to oil products, such as diesel fuel (DF) and motor oil (MO), were determined. The obtained pellets are characterised by a sufficiently pronounced ability to absorb oil products such as DF. As the amount of CR in the granules increases, the diesel absorption capacity increases significantly. The case of 30-70-0 is almost three times higher than the granules from homogenised peat. The increase in q is due to two factors: the pronounced surface hydrophobicity of the samples (Θ = 152°) and a heterogeneous porous granule structure. The presence of the cenosphere in the biocomposite reduces its surface hydrophobicity while increasing the diesel absorption capacity. Relatively rapid realisation of the maximum saturation by the MO was noted. In common, the designed absorbent shows up to 0.7 g·g−1 sorption capacity for MO and up to 1.55 g·g−1 sorption capacity for diesel. A possible mechanism of DF absorption and the limiting stages of the process approximated for different kinetic models are discussed. The Weber–Morris diffusion model is used to primarily distinguish the limiting effect of the external and internal diffusion of the adsorbate on the absorption process. [ABSTRACT FROM AUTHOR]

This paper presents the assumptions of a thermodynamic equation of state for polymers according to the Renner model. The experiments involved extruding a biocomposite based on poly(butylene succinate) that was filled with ground wheat bran with its size not exceeding 200 μm. The biocomposite was produced in pellet form with three different contents by weight of wheat bran, i.e., 10%, 30% and 50%. All specimens were examined for their thermodynamic p-v-T characteristics. Taking advantage of the SimFit module of Cadmould 3D-F, experimental results were used to determine the coefficients of thermodynamic equation of state for the tested biocomposite according to the Renner model. The coefficients were then used to calculate transition temperature and to create diagrams illustrating the relationship between pressure, temperature and specific volume for the tested biocomposite. The obtained results can serve as a basis for assessing the suitability of the biocomposite for injection molding, selecting technological parameters of this process, as well as for analyzing shrinkage and defects of injection-molded parts. [ABSTRACT FROM AUTHOR]

Cellulose represents a low cost, abundant, and renewable polysaccharide with great versatility; it has a hierarchical structure composed of nanofibers with high aspect ratio (3–4 nm wide, hundreds of μm long). TEMPO-mediated oxidation represents one of the most diffused methods to obtain cellulose nanofibers (CNFs): It is possible to obtain physically crosslinked hydrogels by means of divalent cation addition. The presence of inorganic components, such as calcium phosphates (CaP), can improve not only their mechanical properties but also the bioactivity of the gels. The aim of this work is to design and characterize a TEMPO-oxidized cellulose nanofibers (TOCNFs) injectable hydrogel embedded with inorganic particles, CaP and CaP-GO, for bone tissue regeneration. Inorganic particles act as physical crosslinkers, as proven by rheological characterization, which reported an increase in mechanical properties. The average load value registered in injection tests was in the range of 1.5–4.4 N, far below 30 N, considered a reasonable injection force upper limit. Samples were stable for up to 28 days and both CaP and CaP-GO accelerate mineralization as suggested by SEM and XRD analysis. No cytotoxic effects were shown on SAOS-2 cells cultured with eluates. This work demonstrated that the physicochemical properties of TOCNFs-based dispersions could be enhanced and modulated through the addition of the inorganic phases, maintaining the injectability and bioactivity of the hydrogels. [ABSTRACT FROM AUTHOR]

In this publication, novel bio-based composites made of epoxidized natural rubber with 50 mol% of epoxidation (ENR-50) are presented. The obtained materials, partially cured with a totally environmentally friendly crosslinking system consisting of natural ingredients, including quercetin and silica, exhibit a self-healing ability resulting from the self-adhesion of ENR-50 and reversible physical forces between the curing agent and the matrix. The impact of natural components on the crosslinking effect in uncured ENR-50 matrix was analyzed based on rheometric measurements, mechanical tests and crosslinking density. The partially crosslinked samples were next cut into two separate pieces, which were instantly contacted together under a small manual press, left at room temperature for a few days for the healing process to occur and finally retested. The healing efficiency was estimated by measuring mechanical properties before and after the healing process and was also confirmed by photos taken using optical and scanning electron microscope (SEM). According to the results, a combination of silica and quercetin is a totally safe, natural and effective crosslinking system dedicated to epoxidized natural rubber. The novel composites containing ingredients safe for human beings exhibit promising self-healing properties with a healing efficiency of up to 45% without any external stimuli and stand a chance of becoming innovative biomedical materials. [ABSTRACT FROM AUTHOR]

Biotechnological use of probiotic microorganisms involves providing them with appropriate conditions for growth, but also protection against environmental changes caused by an exchange of the medium, isolation of metabolites, etc. Therefore, the research on effective immobilization of probiotic microorganisms should be focused in this direction. The present study aimed to evaluate the effectiveness of an innovative hybrid immobilization system based on electrospun nanofibers and alginate hydrogel. The analyses carried out included the study of properties of the initial components, the evaluation of the degree and durability of cell immobilization in the final material, and their survival under stress conditions. Effective binding of microorganisms to the hydrogel and nanofibers was confirmed, and the collected results proved that the proposed biocomposite is an efficient method of cell protection. In addition, it was shown that immobilization on electrospun nanofibers leads to the preservation of the highest cell activity and the least cell growth restriction as compared to free or lyophilized cells only. The completed research opens new perspectives for the effective immobilization of microorganisms of significant economic importance. [ABSTRACT FROM AUTHOR]

Unmodified poly (butylene succinate) (PBS) is characterized by very good processability; however, after the incorporation of various fillers of plant origin, its processing becomes much more complicated and its properties are significantly affected. Detailed studies of the processing aspects of PBS/wheat bran (WB) biocomposition are lacking, despite the addition of WB having a significant impact on both the production efficiency and the properties of end products. This research paper presents test results of the co-rotating twin-screw extrusion processing of a biodegradable polymer blend, the matrix of which was PBS, with WB as the filler. In undertaking this task, we examined the impact of extruder screw rotational speed and WB content on the characteristics of extrusion processing, as well as on certain thermal, physical, structural and processing properties of the obtained blend. The WB introduced to the blend was in the form of a selected fraction with particles smaller than 0.2 mm. The measurements were conducted using the Design of Experiment (DOE) methods, which enabled establishing the studied relationships in the form of polynomials and response surfaces. The determined extrusion process characteristics covered the impact of screw rotational speed and WB content on the mass flow rate of the processed blend and its pressure, the screw drive torque and specific energy consumption. The studies of the obtained polymer blend included determining the impact of the aforementioned variable factors on the melt flow rate (MFR) index, chemical structure (FTIR), thermal properties (differential scanning calorimetry (DSC), thermogravimetry (TG), derivative thermogravimetry (DTG)), p-v-T relationships, microstructure, density and moisture absorbance. Analysis of variance (ANOVA) was used to assess the effect of individual variable factors. The results of this work are presented, inter alia, using Pareto charts of standardized effects, which illustrate the influence of individual terms of the determined regression equations on the studied quantity. [ABSTRACT FROM AUTHOR]

Bio- and green composites are mainly used in non-structural automotive elements like interior panels and vehicle underpanels. Currently, the use of biocomposites as a worthy alternative to glass fibre-reinforced plastics (GFRPs) in structural applications still needs to be fully evaluated. In the current study, the development of a suited biocomposites started with a thorough review of the available raw materials, including both reinforcement fibres and matrix materials. Based on its specific properties, hemp appeared to be a very suitable fibre. A similar analysis was conducted for the commercially available biobased matrix materials. Greenpoxy 55 (with a biocontent of 55%) and Super Sap 100 (with a biocontent of 37%) were selected and compared with a standard epoxy resin. Tensile and three-point bending tests were conducted to characterise the hemp-based biocomposite. [ABSTRACT FROM AUTHOR]

In this work, the effects of chemical pretreatment and different fiber loadings on mechanical properties of the composites at the sub-micron scale were studied through nanoindentation. The composites were prepared by incorporating choline chloride (ChCl) pretreated rice husk waste (RHW) in low-density polyethylene (LDPE) using melt processing, followed by a thermal press technique. Nanoindentation experiments with quasi continuous stiffness mode (QCSM) were performed on the surface of produced composites with varying content of pretreated RHW (i.e., 10, 15, and 20 wt.%). Elastic modulus, hardness, and creep properties of fabricated composites were measured as a function of contact depth. The results confirmed the appreciable changes in hardness, elastic modulus, and creep rate of the composites. Compliance curves indicated that the composite having 20 wt.% of pretreated RHW loading was harder compared to that of the pure LDPE and other composite samples. The values of elastic modulus and hardness of the composite containing 20 wt.% pretreated RHW were increased by 4.1% and 24% as compared to that of the pure LDPE, respectively. The creep rate of 42.65 nm/s and change in depth of 650.42 nm were also noted for the composite with RHW loading of 20 wt.%, which showed the substantial effect of holding time at an applied peak load of 100 mN. We believe that the developed composite could be a promising biodegradable packaging material due to its good tribo-mechanical performance. [ABSTRACT FROM AUTHOR]

Type I collagen and nanocrystalline-substituted hydroxyapatite are the major components of a natural composite—bone tissue. Both of these materials also play a significant role in orthopedic surgery and implantology; however, their separate uses are limited; apatite is quite fragile, while collagen's mechanical strength is very poor. Therefore, in biomaterial engineering, a combination of collagen and hydroxyapatite is used, which provides good mechanical properties with high biocompatibility and osteoinduction. In addition, the porous structure of the composites enables their use not only as bone defect fillers, but also as a drug release system providing controlled release of drugs directly to the bone. This feature makes biomimetic collagen–apatite composites a subject of research in many scientific centers. The review focuses on summarizing studies on biological activity, tested in vitro and in vivo. [ABSTRACT FROM AUTHOR]