Production Of Biocomposites Research Articles

Sustainable production of Pleurotus sajor-caju mushrooms and biocomposites using brewer’s spent and agro-industrial residues

Brazil is one of the world’s largest beer producers and also a major food producer. These activities generate a large amount of residues which, if disposed of inappropriately, can have adverse effects on the environment. The objective of this research was to evaluate the potential of using these residues for both mushroom cultivation (traditional use) and the production of mycelium-based composites (innovative use). Mushroom production (Pleurotus sajor-caju) was conducted using only brewer’s spent grains (fresh and dried) and also mixed with banana leaves (1:1) or peach palm leaves (1:1), which are residues widely available in the northern region of Santa Catarina, Brazil. The productivity of mushrooms cultivated using fresh and dried brewer’s spent grains did not exhibit a statistically significant difference, indicating that this residue can be utilized shortly after its generation in the industrial process, thereby reducing costs associated with production. Combining brewer’s spent grains with banana or peach palm leaves resulted in enhanced mushroom production (0.41 and 0.38 g day−1, respectively) compared to using the leaves as a sole substrate. The mushrooms produced contain sugars and a minimal sodium content, and are considered a source of phosphorus. In addition, no toxic elements (Hg and Pb) were present. The mycelium-based composites produced using the residual substrate (after the mushroom harvest) exhibited better mechanical properties (compressive strength = 0.04 MPa, density = 242 kg m−3, and low humidity sorption) than those produced using fresh substrate. The results demonstrate the synergistic effect of combining the two approaches under investigation. The use of brewer´s spent enhance the mushroom productivity and the residual substrate enhance the mechanical properties of mycelium-based composites. The compressive strength, density, and air humidity sorption properties are essential for determining the potential applications of mycelium-based composites. The use of brewer’s spent grains mixed with banana leaves demonstrated significant promise for mushroom production and subsequent application in the development of mycelium-based composites. These sequential approaches contribute to waste valorization and the rational utilization of natural resources, as the mycelium-based composites are considered for substitution of synthetic materials, thereby promoting sustainability for future generations.

Improved Adhesion of Bacterial Cellulose on Plasma-Treated Cotton Fabric for Development of All-Cellulose Biocomposites.

Cellulose produced by bacteria (BC) is considered a promising material for the textile industry, but the fragile and sensitive nature of BC membranes limits their broad applicability. Production of all-cellulose biocomposites, in which the BC is cultivated in situ on a cotton fabric, could solve this problem, but here a new issue arises, namely poor adhesion. To overcome this challenge, cotton fabric was modified with low-pressure oxygen plasma in either afterglow, E-mode, or H-mode. All-cellulose biocomposites were prepared in situ by placing the samples of cotton fabric in BC culture medium and incubating for 7 days to allow BC microfibril networks to form on the fabric. Modification of cotton fabric with oxygen plasma afterglow led to additional functionalization with polar groups, and modification with oxygen plasma in H-mode led also to etching and surface roughening of the cotton fibers, which improved the adhesion within the biocomposite. In addition, these biocomposites showed higher deformation capacities. Modification of the cotton fabric over a longer period in E-mode was found to be unsuitable, as this caused strong etching, which led to the defibrillation of cotton fibers and poor adhesion of BC. This study highlights the potential of low-pressure plasma treatment as an environmentally friendly method to improve the performance of cellulose-based biocomposites.

Bio-composites from barley, wheat, and cassava flours reinforced with oil palm residues: Characterization and tensile mechanical performance

This study explores the production of bio-composites from barley, wheat, and cassava flours, reinforced with varying ratios of oil palm residues. The research emphasizes principles of circular economy and sustainability. Both flours and reinforcements underwent characterization to elucidate how their physicochemical properties affect the mechanical behavior of the bio-composites. Barley flour exhibited significantly higher levels of protein (11.11 %), crude fiber (5.64 %), and ash (2.80 %) compared to wheat and cassava flours. Conversely, cassava flour stood out for its high carbohydrate concentration (approximately 97.8 % on a dry weight basis). Characterization highlighted enhanced adhesion between reinforcements in bio-composites with cassava flour, alongside morphological distinctions on fractured surfaces. Fourier-transform infrared (FTIR) analysis unveiled several functional groups in the bio-composites, while thermogravimetric analysis delineated five stages of thermal degradation. In terms of mechanical properties, bio-composites with barley flour showed higher elastic modulus values (970.5 MPa), while those with 12 % OPKS exhibited tensile strengths of 1.7–2.1 MPa. The interaction among components emerged as a fundamental factor influencing the mechanical properties of bio-composites, underscoring the necessity of considering reinforcement composition and distribution during fabrication.

Green and sustainable bamboo based composites with high self-bonding strength

Self-bonding technology is a forming method utilized for the production of bio-composites with notable advantages in terms of high strength and water resistance, while also being free from formaldehyde. The successful achievement of high-strength self-bonding biomaterials has been demonstrated, however, most of these achievements have relied on various surface chemical modifications with limited attention given to exploring non-additive approaches. This study aimed to investigate the feasibility of self-bonding formation through examining the effects of particle dispersion, lignin melting, and chemical bonding, in distinct unit morphologies without the use of any chemical additives. Also, the self-bonding mechanism of bamboo based composites (BBCs) was revealed, by examination of its microstructure, chemical composition and thermal stability. The findings indicated that raw component morphologies based on power, fiber, and bundle all effectively achieved high-strength self-bonding structures at a temperature of 155 °C, a pressure of 55 MPa, and a duration time of 60 min. The density of the BBCs approached that of solid cell wall in bamboo, reaching a maximum of 1.44 g/cm3. The morphology of raw components had significant effect on the self-bonding performance of BBCs, with the powder exhibiting the highest performance, followed by the bundles, and the fibers showing the lowest. The powder-based BBC demonstrated a remarkable flexural strength of 61 MPa, a notable surface hardness of 32.5 kgf/mm and low 24 h thickness swelling of 6.8 %, all much more excellent than those observed in ordinary panels. The BBCs demonstrated the benefits of being environmentally friendly (free from formaldehyde), processing excellent water resistance and strong mechanical strengths. They were suitable for use in high-humidity environments and can meet the requirements for strong load-bearing conditions, even replacing some metal sliding bearing materials.

Effect of Wood Species on Lignin-Retaining High-Transmittance Transparent Wood Biocomposites.

This study explores lignin-retaining transparent wood biocomposite production through a lignin-modification process coupled with epoxy resin. The wood's biopolymer structure, which includes cellulose, hemicellulose, and lignin, is reinforced with the resin through impregnation. This impregnation process involves filling the voids and pores within the wood structure with resin. Once the resin cures, it forms a strong bond with the wood fibers, effectively reinforcing the biopolymer matrix and enhancing the mechanical properties of the resulting biocomposite material. This synergy between the natural biopolymer structure of wood and the synthetic resin impregnation is crucial for achieving the desired optical transparency and mechanical performance in transparent wood. Investigating three distinct wood species allows a comprehensive understanding of the relationship between natural and transparent wood biocomposite properties. The findings unveil promising results, such as remarkable light transmittance (up to 95%) for Aspen transparent wood. Moreover, transparent wood sourced from White Spruce demonstrates excellent stiffness (E = 2450 MPa), surpassing the resin's Young's modulus. Also, the resin impregnation enhanced the thermal stability of natural wood. Conversely, transparent wood originating from Larch showcases superior impact resistance. These results reveal a clear correlation between wood characteristics such as density, anatomy, and mechanical properties, and the resulting properties of the transparent wood.

Sustainable 3D-printed cellulose-based biocomposites and bio-nano-composites: Analysis of dielectric performances

The development of cellulose-reinforced biomaterials appears to be an attractive approach for the production of sustainable materials with good mechanical properties. Although 3D printing of cellulose-reinforced biomaterials has become popular, there is very little feedback regarding their use in electrical insulation applications. This study aims to propose bio-nano-composites containing polylactic acid (PLA), microcrystalline (MCC) and nanocrystalline (NCC) cellulose by fused filament fabrication (FFF) for electrical insulation applications. The influence of the 3D printing process, cellulose content and filler size on dielectric properties was investigated. The addition of cellulosic fillers, and considering their high polarity, increased the dielectric constant (ε'), dielectric loss (ε''), as well as the AC electrical conductivity (σAC) of the composites. Cellulosic fillers also increased the crystallization rate of the materials. At equivalent content, the highest polarization potential were observed for NCC-based composites and were attributed to the nanofiller's better dispersion and available specific surface area. Finally, the 3D printing process affects all the measured properties, due to a combined effect (lower crystalline content and voids presence). The porosity rate was measured at 2.5 % for the neat PLA and increased progressively from 3.1 % to 5.8 % for the cellulose-based composites. These findings showed the benefits provided by the FFF technology in the production of cellulose-based biocomposites with good electrical insulation properties, while noting some needed feedback on the thermomechanical properties of such materials.

Layer-by-layer coated cellulose reduces the fire risk of polyurethane foam biocomposites

Cellulose implementation as filler in polyurethane foams (PUF) often leads to an increased the fire risk associated to the prepared biocomposite. To address this problem, this paper presents a novel approach where the cellulose filler is coated by a nanostructured layer-by-layer (LbL) assembly with flame retardant characteristics before its addition to the biocomposite. During PUF production, the presence of cellulose led to a reduced cell size distribution with improved thermal insulation properties. By forced combustion tests, the use of neat cellulose produced a detrimental effect by increasing the PUF heat release rates (up to +21 %). Conversely, the coated cellulose simultaneously decreased the peak of heat release rate (-22 %) and the total smoke release (-32 %) if compared with the reference PUF. The proposed approach represents a viable strategy for the production of PUF biocomposites where sustainability and fire protection are optimized.

Sustainable and multifunctional polyurethane green composites with renewable materials

Polyurethane materials are characterised by an ever-expanding range of application possibilities due to their versatility. Currently, the management of leftovers as well as post-production and post-consumer waste for the production of biocomposites is one of the most obvious, effective and profitable solutions. Due to the renewable nature of biofillers such as cellulose, lignin, and chitin, their use to obtain composite polyurethane elastomers is a real perspective for the dissemination of more environmentally friendly materials and, at the same time, contributes to additional economic profit. The key aspect for further development of the polyurethane/biopolymer biocomposite concept is to fulfil of a number of currently functioning industry standards, mainly those regarding functional properties. In the presented research, an attempt to obtain advanced polyurethane elastomers with the addition of biopolymers (cellulose, lignin, and chitin) was conducted for the first time. The innovative biocomposites obtained in this way were characterised by good processing parameters (processing times, density) and improved functional properties compared to the standard without the addition of fillers (abrasion resistance, tensile strength, contact angle, hardness). Due to the above-mentioned facts, the described biocomposites can be successfully used for the production of multifunctional elastomeric materials with a wide range of potential applications. Moreover, it is worth noting that the management of waste materials in this way will reduce production costs while indirectly contributing to the protection of the natural environment.Graphical abstract

Bridging gap between agro-industrial waste, biodiversity and mycelium-based biocomposites: Understanding their properties by multiscale methodology

A multiscale methodology approach was employed integrating microscopic analysis of the biomasses present in the biocomposite (lignocellulosic and fungal) to understand their macroscopic response in terms of physical and mechanical properties. Colombian native strain Ganoderma gibbosum, used for the first time in the production of biocomposites was cultivated on peach palm fruit peel flour and sugar cane bagasse wet dust, individually and as a mixture. During the solid-state fermentation were monitoring the change that occurred in substrate composition such as glucan, arabinoxylan, and lignin through biomass compositional analysis using structural carbohydrates and lignin. Moreover, fungal biomass formation was monitored via scanning electron microscopy. The resulting biocomposites underwent characterization through flexural and water absorption tests. Our findings indicated that G. gibbosum primarily degraded the polysaccharides in each of the evaluated media. However, lignin degradation to 15.06 g/g was only observed in the mixture biocomposite of peach palm fruit peel fluor and sugarcane bagasse wet dust in a ratio of 1꞉1, accompanied by a reduction in glucan and arabinoxylan weights to 26.1 and 7.72 g/g, respectively. This polymer degradation, combined with a protein-rich source in the mixture biocomposite of peach palm fruit peel fluor and sugarcane bagasse wet dust in a ratio of 1꞉1, facilitated the production of a fungal skin (biological matrix) with a high hyphal density of 65%, contributing to Young's modulus of 3.83 MPa, elongation without failure, and low water absorption rate in this biocomposite (55%). The lignocellulosic biomass in the culture media acted as a filler for mechanical interlocking with the matrix and provided attachment points for water absorption. Thus, our study establishes a connection between the microscopic scale and the macroscopic behavior of this biocomposite, assessing structural carbohydrates and lignin analysis during solid-state fermentation (SSF), laying the groundwork for a more customized design of mycelium-based biocomposites. Finally, this study demonstrates the possibility of tailoring nutrient composition by designing their culture media to obtain physical-mechanical properties according to the application requirement.

New HCHO-scavenger for enhancing the HCHO-based adhesive in production environmentally friendly agro-based composites

Recently, green products are essential requirements. This work deals with synthesizing novel formaldehyde-scavenger based on black liquor to enhance the urea-formaldehyde (UF) adhesive for production of eco-friendly bio-composites. These HCHO-scavengers are synthesized from black liquor-based aerogel precursors. The assessment is carried out via estimating the HCHO adsorption capacities versus type of black liquor; as well as its beneficial effect on characterization of UF adhesive (Differential Scanning Calorimetry (DSC)-curing temperature; gel time and adhesive strength). The UF-scavenger system, which provides palm fiber-composite with properties (static bending, internal bond, and free-HCHO) compliance with the standard specifications is optimized. The data evidenced the effective role of black liquor (BL) from alkali pulping RS in presence of borohydride in resulting aerogel precursor of scavenger with higher HCHO-adsorption capacities (∼64 mg/g) than that produced from native aerogels (AG) in absence of BL. The kinetic adsorption is most applicable with the pseudo-second order equation. This observed behavior reflected on reducing the gel time and improved the bond strength of scavenger (Scv)-UF systems. It is interesting to note that all investigated BL-scavengers provide reduction in free HCHO of palm composites (from 30.7 mg/100g to 5–11 mg/g). These values are lower than that obtained from scavengers in absence of BLs (17.4 mg/100g). Based on the value of free-HCHO and mechanical properties, we recommend the scavenger resulted from black liquor of alkali pulping RS in presence of anthraquinone and borohydride (NaOH-AQ-BH) of screened RS as effective scavenger to provided eco-palm-wood composites with MOR, MOE, IB, free-HCHO and thickness swelling ∼ 27 MPa, 0.72 MPa, 7157 MPa, 7 % and 11 %, respectively. According to international standard specifications this type of palm-composite fulfills the grade H-3 and E1 according to environmental specification.

Extraction of cellulose nanocrystals from Cissus quadrangularis for sustainable biocomposite production

Extraction of cellulose nanocrystals from Cissus quadrangularis for sustainable biocomposite production

Experimental investigation on strengthening of Zea mays root fibres for biodegradable composite materials using potassium permanganate treatment

Humans are the only species who generate waste materials that cannot be broken down by natural processes. The ideal solution to this waste problem would be to employ only compostable materials. Biodegradable materials play a key role in creating a safer and greener world. Biodegradability is the gift that keeps on giving, in the sense of creating an Earth worth living. The future is thus best served by green energy, sustainability, and renewable resources. To realize such goals, waste should be considered as a valuable resource. In this context, Zea mays (Zm) root fibres, which are normally considered as agricultural waste, can be used as reinforcing substances in polymer matrices to produce structural composite materials. Before being used in composites, such fibres must be analysed for their physical properties. Chemical treatments can be employed to improve the structural quality of fibres, and the changes due to such modification can be analysed. Therefore, the current work examines the effect of permanganate treatment on the surface properties of Zm fibres. The raw and potassium permanganate-treated samples were assayed for various properties. Physical analysis of the fibre samples yielded details concerning the physical aspects of the fibres. The thermal conductivity and moisture absorption behaviour of the samples were analysed. Chemical analysis was employed to characterize the composition of both treated and untreated samples. p-XRD was employed to examine the crystalline nature of the Zm fibres. Numerous functional groups present in each sample were analysed by FTIR. Thermogravimetric analysis was used to determine the thermal stability of Zm fibres. Elemental analysis (CHNS and EDS) was used to determine the elemental concentrations of both raw and treated samples. The surface alterations of Zm fibres brought on by treatment were described using SEM analysis. The characteristics of Zm roots and the changes in quality due to treatment were reviewed, and there were noticeable effects due to the treatment. Both samples would have applications in various fields, and each could be used as a potential reinforcing material in the production of efficient bio-composites.

Effect of treatment conditions on the morphology of date empty fruit bunch lignocellulosic fiber for biocomposite applications

The fiber of the empty date fruit is one of the waste products left after the date fruit is harvested from the date palm. Optimization of the treatment parameters as well as the economics of the treatment process are critical to the successful commercialization of the treatment of natural fibers for the production of biocomposites. Of the natural fiber treatment methods described in previous work, hot water and alkali treatments are the most cost-effective, which justified the choice of these treatment methods in this work. Here, date empty fruit bunch fibers were pulverized to a particle size of 0–500 µm and then treated with boiling water at 100 °C for 3 h or with sodium hydroxide at different concentrations (2, 5, 10%) for 3 h at room temperature with constant stirring at 800 rpm. To confirm the effect of temperature on the fiber treatment, another fiber sample was treated at a 5% concentration of sodium hydroxide solution at an elevated temperature of 80 °C for the same period and stirring condition. The untreated and treated DEFB fibers were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray fluorescence (XRF), and scanning electron microscopy (SEM). Chemical analysis of the fibers showed that DEFB fiber treated with 5% sodium hydroxide solution at room temperature had the highest cellulose content (52.0%), which was also confirmed by the XRD analysis. The DEFB fiber treated with boiling water exhibited higher thermal stability while the sodium hydroxide-treated fiber exhibited higher crystallinity index and cellulose content. Apparently, DEFB fiber treated with sodium hydroxide solution at 5% concentration for 3 h at room temperature for continuous stirring at 800 rpm offered the best properties. The treated fibers are expected to be viable reinforcement in the production of biocomposites with the goal of achieving energy efficiency. The developed materials could be used in industrial applications such as insulating building systems, automotive parts, and home furniture.

Fabrication and characterization of biocomposite pellets from cassava starch and oil palm empty fruit bunch fibers

Oil palm empty fruit bunches (OPEFB) are lignocellulosic biomass that can be used to produce a biocomposite as an alternative to substitute non-renewable materials, such as plastic. Generally, the production of biocomposites uses OPEFB, which has been processed into cellulose, microcrystalline cellulose, or nanocellulose and is mixed with starch. However, the OPEFB pretreatment into various types of cellulose requires a long process and many chemicals. The OPEFB pretreatment with less process, such as cutting to shorter fibers and without chemicals, was expected to shorten the process. This study aims to produce and evaluate the characteristics of biocomposite pellets from a combination of cassava starch and OPEFB fibers. Short OPEFB fibers (3-5 mm) with varying concentrations of 0, 5, 10, 15, and 20% were added to the cassava starch before mixing with other materials. The twin screw extruder used to produce biocomposite pellets was set at six temperature zones ranging from 85-140 °C and the screw speed in the range of 160-190 rpm. The results show that higher concentrations of OPEFB fibers produced darker pellets, which tended to be greyish. The biocomposite pellets had densities of 1.322-1.417 g cm-3. SEM results show some agglomerations on the surface of starch-OPEFB fibers biocomposite pellets. The water solubility of biocomposite pellets ranged from 32.97 – 36.44%. In conclusion, biocomposite pellets could be produced from a mixture of cassava starch and OPEFB fibers up to 20%. In its application for rigid packaging production, the biocomposite pellets’ performance could be improved by mixing them with recycled polypropylene.

Bio-Polyethylene and Polyethylene Biocomposites: An Alternative toward a Sustainable Future.

Polyethylene (PE), a highly prevalent non-biodegradable polymer in the field of plastics, presents a waste management issue. To alleviate this issue, bio-based PE (bio-PE), derived from renewable resources like corn and sugarcane, offers an environmentally friendly alternative. This review discusses various production methods of bio-PE, including fermentation, gasification, and catalytic conversion of biomass. Interestingly, the bio-PE production volumes and market are expanding due to the growing environmental concerns and regulatory pressures. Additionally, the production of PE and bio-PE biocomposites using agricultural waste as filler materials, highlights the growing demand for sustainable alternatives to conventional plastics. According to previous studies, addition of ≈50% defibrillated corn and abaca fibers into bio-PE matrix and a compatibilizer, results in the highest Young's modulus of 4.61 and 5.81GPa, respectively. These biocomposites have potential applications in automotive, building construction, and furniture industries. Moreover, the advancement made in abiotic and biotic degradation of PE and PE biocomposites is elucidated to address their environmental impacts. Finally, the paper concludes with insights into the opportunities, challenges, and future perspectives in the sustainable production and utilization of PE and bio-PE biocomposites. In summary, production of PE and bio-PE biocomposites can contribute to a cleaner and sustainable future.

Sustainable 3D printed poly (lactic acid) (PLA)/Hazelnut shell powder bio composites for design applications

In the context of seeking sustainable solutions for developing innovative materials and products by an efficient use of natural resources and recycling waste, with an increasing focus on circular economy and mitigating environmental impact, the presents research aims to use biomass and agricultural residues as raw materials for bio composite production. Specifically, valorizing European hazelnut waste presents a unique opportunity to devise innovative formulations for 3D printing, leveraging both the mechanical properties and aesthetic appeal of lignocellulosic bio composites. In detail, this work aimed at the investigation of new poly(lactic acid) (PLA)/Hazelnut Shell Powder formulations for 3D printing design applications exploiting the woody aesthetic effect of these bio composites. A pellet 3D printer was used to bypass the filament production. Three different Hazelnut Shell Powder content (from 10 up to 30 wt%) were investigated and a design of experiment was carried out to generate response surfaces able to identify the best printing conditions to optimize flexural, tensile and impact properties. Finally, the effect of three different raster angles (0°, ±45° and 90°) on the mechanical properties was investigated. The best configuration was: 220 °C of nozzle temperature, 25 mm/s of printing speed and ±45° of raster angle. With this configuration, prototypes of ornamental pots, jewellery and home furniture were produced as demonstrators.

Human health risk assessment framework for new water resource recovery-based bio-composite materials.

A new type of bio-composite material is being produced from water-recovered resources such as cellulose fibres from wastewater, calcite from the drinking water softening process, and grass and reed from waterboard sites. These raw materials may be contaminated with pathogens and chemicals such as Escherichia coli, heavy metals, and resin compounds. A novel risk assessment framework is proposed here, addressing human health risks during the production of new bio-composite materials. The developed framework consists of a combination of existing risk assessment methods and is based on three main steps: hazard identification, qualitative risk mapping, and quantitative risk assessment. The HAZOP and Event Tree Analysis methodologies were used for hazard identification and risk mapping stages. Then, human health risks were quantitatively assessed using quantitative chemical risk assessment, evaluating cancer and non-cancer risk, and quantitative microbial risk assessment. The deterministic and the stochastic approaches were performed for this purpose. The contamination of raw materials may pose human health concerns, resulting in cancer risk above the threshold. Microbial risk is also above the safety threshold. Additional analysis would be significant as future research to better assess the microbial risk in biocomposite production. The framework has been effectively used for chemical and microbial risk assessment.

Sustainable Biocomposites: Harnessing the Potential of Waste Seed-Based Fillers in Eco-Friendly Materials

With the growing concerns over environmental degradation and the increasing demand for sustainable materials, eco-friendly composites have gained considerable attention in recent years. This review paper delves into the promising realm of seed-based fillers, reinforcements and polysaccharidic matrices in the production of biocomposites that are yet focusing on those seeds, which can be considered industrial process waste. Seeds, with their inherent mechanical properties and biodegradability, which are often the waste of production systems, offer a compelling solution to reduce the environmental impact of composite materials. This paper explores the properties of various seeds considered for composite applications and investigates the processing techniques used to incorporate them into composite matrices. Furthermore, it critically analyzes the influence of seed fillers on the mechanical and physical properties of these eco-friendly composites, comparing their performance with traditional counterparts. The environmental benefits, challenges, and limitations associated with seed-based composites from waste seeds are also discussed, as well as their potential applications in diverse industries. Through an assessment of relevant case studies and research findings, this review provides valuable insights into the outlook of seed-based composites as a sustainable alternative in the composite materials landscape, emphasizing their role in promoting a greener and more responsible approach to materials engineering.

Modeling and formulation/process parameters design methodological approaches for improving the performance of biocomposite materials for building, construction, and automotive applications: A state-of-the-art review

In today’s manufacturing sector, high-quality materials that satisfy customers’ needs at a reduced cost are drawing attention in the global market. Also, as new applications are emerging, high-performance biocomposite products that complement them are required. The production of such high-performance materials requires suitable optimization techniques in the formulation/process design, not simply mixing natural fibre/filler, additives, and plastics and characterization of the resulting biocomposites. However, a comprehensive review of the optimization strategies in biocomposite production intended for infrastructural applications is lacking. This study, therefore, presents a detailed discussion of the various optimization approaches, their strengths, and weaknesses in the formulation/process parameters design of biocomposite manufacturing. The report explores the recent progress in optimization techniques in biocomposite material production to provide baseline information to researchers and industrialists in this field. Therefore, this review consolidates prior studies to explore new areas.

The development of glutin-based biocomposite materials with advanced hydrophobicity

Biocomposite materials, which contain components of natural origin, have low resistance to water absorbtion due to high lyophilicity of components. It leads to quick destruction of biocomposite products under the conditions of high humidity exploitation that defines the necessity and importance of conducting scientific research in this sphere. The aim of the article is to research the hydrophobic additives influence on the compressive strength and hygroscopicity of biocomposite materials consisting of glutin matrix (100 parts by weight) and wood flour (100 parts by weight). The technology of forming biocomposite materials includes a step-by-step pressing the composition at a pressure of 10-15 MPa and a heat treatment of the product in a press mold at a temperature of 140°C. Experimental methods of investigating the biocomposite materials compressive strength and hygroscopicity were used in the work. It was experimentally determined that the modifying additive (paraffin) optimal content is 4 parts by weight per 100 parts by weight of biopolymer matrix. At this content, there is an increase compressive strength by 2.8-4.6 times of the biocomposite materials compared to biocomposites with different paraffin content. As a result of the state analysis of biocomposite samples which were destroyed under the static loading influence, the features of the cracks occurrence and propagation in biocomposites depending on different modifying additive content, the conduct of the composition preliminary processing or biocomposites additional processing in a thermal field were determined. The use of protective hydrophobic coatings on the biocomposite samples surface provided an increase in the biocomposites resistance to the moisture negative influence. The most effective were coatings based on a paraffin solution, which provided a reduction in water absorption by 45-50% compared to biocomposites coated with wax, drying oil Oksol, and sunflower oil. The complex use of hydrophobic substances as modifying additives and protective coatings has practical significance, as they positively affect the processes of forming the structure, increasing the strength and hydrophobicity of biocomposite materials used in a humid environment