Papers by Keyword: Biocomposite

Abstract: Despite the growing use of biopolymers in automotive, packaging and structural applications, predictive modelling of their elastic–viscoplastic deformation remains limited. In this work, a micromechanically based constitutive model is proposed to describe the micro‑ to macroscopic behaviour of a semi‑crystalline PLA matrix reinforced with short hemp fibers. The formulation relies on a multiplicative split of the deformation gradient into elastic and viscoelastic–plastic parts, with elasticity governed by fiber and crystalline phases and time‑dependent deformation localized in the amorphous phase. High fiber content and strong fiber–matrix bonding enable the suppression of lattice crystalline anisotropy, leading to a compact model with a reduced number of internal variables. The model is calibrated and validated using uniaxial tensile tests on pellet‑extrusion 3D‑printed specimens with controlled porosity and plasticiser content, and reproduces nonlinear loading, unloading, creep and stress relaxation. In a second step, synthetic data generated by the constitutive model are used to train surrogate machine‑learning models, which are discussed as a perspective for accelerating long‑term simulations and parametric studies in forming applications.

Abstract: This study analysed the mechanical performances and the environmental sustainability of hybrid hemp/carbon fibre reinforced polymer composites produced adopting different stacking sequences. In this context, three carbon layers were replaced with hemp ones and were positioned either at the mid-plane of the laminate in a symmetric configuration (S sample) and near to the external side of the composite material in an asymmetric configuration (A-HC sample). Additional full carbon sample (CFRP) and hemp sample (HFRP) were manufactured and used as reference materials. The mechanical behaviour of these materials was investigated through flexural, interlaminar shear and low-velocity impact (LVI) tests, and a cradle-to-grave Life Cycle Assessment (LCA) analysis was performed to quantify their environmental impacts in terms of Global Warming Potential (GWP). The experimental results revealed that hemp/carbon hybridisation in composite systems makes it possible to achieve a trade-off between mechanical performances and sustainability. Some of the investigated hybrid configurations exhibited mechanical properties comparable to conventional CFRPs thanks to strength, stiffness and enhanced energy absorption capability which depend on the stacking strategy and the presence of natural fibres that contribute to the damage mitigation. From an environmental perspective, thanks to numerous advantages in the use of hemp fibres, hybrid solutions significantly reduce the global warming potential compared to CFRPs, confirming that hemp/carbon hybridisation represents a promising strategy to balance structural performance and environmental.

Abstract: The growing demand for sustainable materials has driven interest in bio-based composites for additive manufacturing (AM). This study explores the feasibility of incorporating untreated coconut fibres into commercial photopolymer resins for stereolithography (SLA). Coconut fibres were extracted, processed, and integrated at varying concentrations into resin formulations, followed by fabrication of ASTM D638 Type IV specimens using a desktop SLA printer and UV post-curing. Mechanical characterization included tensile testing to assess Young’s modulus, tensile strength, and elongation at break, complemented by microscopy of fracture surfaces to evaluate fibre dispersion and failure mechanisms. Results indicate good compatibility between coconut fibres and photopolymer resin, with mechanical performance strongly influenced by fibre content. These findings highlight the potential of coconut fibre-reinforced photopolymer composites as sustainable alternatives for AM applications.

Abstract: Mycelium-based composite (MBC), as a new engineering biocomposite, is receiving numerous interests due to its environmental sustainability. The study aimed to address the challenge of optimizing the physical properties of MBC for a more efficient production process. The study investigated the impact of hot or cold pressing, different pressing temperatures (120 °C, 160 °C, and 200 °C), pressing pressures (low, medium and high) and sequences (before and after drying process) on the physical properties of MBC such as density, shrinkage, moisture content and hardness. Mycelium millets were mixed with kenaf, carbon carbonate, wheat bran and wheat flour. The pressing methods and sequences significantly affected the properties of the MBC. Cold pressing had no effect on reducing shrinkage and moisture content of MBC but improved density. Hot pressing increased hardness at higher temperature and pressure, with strong mycelium-substrate bonding and less porosity observed in SEM image. The post processing sequence involving drying followed by hot pressing at 200°C exhibited higher density, hardness, less shrinkage and controllable moisture content of MBC for better dimensional stability and quality control purpose. It was crucial to optimize MBC pressing techniques for specific applications and ensure that it satisfied the demanding standards of companies looking for sustainable alternatives and cost-effective production.

Abstract: This study investigates the functional groups of 3D printing material filaments made from biocomposites using polymers and natural fibers, analyzed through FTIR spectroscopy. The process of making 3D printing filament uses the extrusion method with a single extrusion machine. The integration of natural fibers into polymer matrices provides a sustainable alternative for 3D printing materials, improving mechanical properties while reducing environmental impact. FTIR analysis revealed significant interactions between polymer and fiber components, identifying key functional groups such as hydroxyl and carbonyl that are critical for performance. Functional groups such as hydroxyl (-OH) and carbonyl (C=O) significantly influence the quality of biocomposites through their impact on the material's mechanical, thermal, and interfacial properties. These findings provide insight into the structure-property relationship of these materials, demonstrating their potential for sustainable 3D printing applications.

Abstract: Pineapple leaf is a significant agricultural waste in pineapple processing plants. The leaf comprises several carbohydrate polymers, including cellulose, hemicellulose and lignin. This research investigated the use of microcrystalline cellulose (MCC) extracted from pineapple leaves as a reinforcing agent in polycaprolactone (PCL) biopolymer at various MCC concentrations. MCC was extracted from pineapple leaves through several processes, including alkali treatment with sodium hydroxide (NaOH), bleaching with sodium hypochlorite (NaOCl), and acid hydrolysis with oxalic acid. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of cellulose from the extracted MCC, and field emission scanning electron microscopy (FESEM) analysis revealed that the particles are of micro-size. The tensile testing results show that the elastic modulus of PCL-based biocomposite increases with higher MCC concentrations. The stiffness of the biocomposites increased by up to 9.5% with the addition of 2 wt.% of MCC as a reinforcing filler, indicating that MCC effectively enhances the mechanical properties of the biocomposite.

Abstract: Oil palm empty fruit bunches (OPEFB) are wastes from oil palm processing. The objective of this work is to study the effect of composition on the physical, mechanical, and thermal properties of OPEFB epoxy resin biocomposite. Particles of OPEFB (100 mesh) were mixed with epoxy resin with the ratio of OPEFB to epoxy resin 60/40, 70/30, 80/20, and 90/10 (vol.%/vol.%). Biocomposites were produced by a press method at room temperature with 9 tons-load. The physical properties (density, porosity, water absorption, thickness swelling) of the biocomposite were evaluated. The mechanical properties (modulus of rupture and modulus of elasticity) of biocomposite were determined by using a universal testing machine. The thermal gravimetric analyzer (TGA) was used to examine the thermal properties of the biocomposite. The results show that the density of biocomposite is 1.18 g/cm³ for 60 vol.% of OPEFB composition. It decreases significantly as the OPEFB composition increases. For 60 vol.% of OPEFB, the porosity, water absorption, and thickness swelling of biocomposite (after soaking in water for 24 hours) are 11.9%, 10.1%, and 6.5%, respectively. All these values increase significantly with the increase of OPEFB composition. For 60 vol.% of OPEFB, the modulus of rupture (MOR) and modulus of elasticity (MOE) of biocomposite are 2.31 kgf/mm² and 267 kgf/mm², respectively. The values of MOR and MOE decrease significantly with the increase in OPEFB composition. TGA results show that degradation of biocomposites occurs significantly at 350°C for 60 vol.% OPEFB. The degradation temperature reduces as the composition of OPEFB increases. In general, the physical, mechanical, and thermal properties of biocomposites decrease with increasing OPEFB composition. This happens because the bond between the matrix and the particles decreases as the OPEFB composition increases. The maximum OPEFB composition that can be used for particleboard applications is 80 vol.%, which meet the ANSI 208.1-2009 requirements for application as grade M-2 particleboard.

Abstract: The concerns towards sustainable development have triggered the need of adopting biodegradable products in different applications. The natural fibers are being widely explored in the field of composites for various applications. Sustainable architecture is also seeking the research and development of new materials to minimize the negative environmental effect of the traditional structural materials. A bast fiber obtained from Grewia Optiva (G.O.) tree is abundantly available in the sub-Himalayan terrains and is still underutilized in the field of biocomposites. The promotion of G.O. fiber in fabrication of biocomposites may give a source of income and employment to rural hilly populations. This research work utilizes the G.O. fiber collected from the Okhalkanda block of Nainital district of Uttarakhand to develop biocomposites. The effect of mercerization on the water absorption behavior and mechanical properties has been also studied. It is found that the treatment of fibers with NaOH reduces the water absorption tendency of G.O. Natural Fiber Reinforced Biocomposites (NFRB) upto 41.05% and the mechanical properties are also improved by appreciable amount. The tensile and flexural strength obtained are 141.45 MPa and 109.84 MPa respectively for mercerized fiber reinforcement. Impact strength and mode-I fracture toughness have been recorded as 11.97 KJ/m² and 1.85 MPa√m respectively. SEM images of fractured surfaces indicate good bonding of mercerized fibers as compared to untreated fibers with epoxy matrix. Hence the Grewia Optiva biocomposites have potential to be used in different architectural applications like wall panels, false ceilings, doors, windows, etc.

Abstract: Hydroxyapatite is naturally found in bone tissue. Tissue engineering often utilizes synthetic hydroxyapatite biocomposite for bone alloplastic grafting. The bone graft shape and size accuracy can be realized using three dimensions (3D) printing technology. The most important part of the 3D printer is an extruder producing printable filament of the material. This work presents a design of the extruder employed to create a gelatine filament. The gelatin will be used as the matrix of a hydroxyapatite biocomposite in the future. The main components of the extruder are a 10 mL acrylic syringe and a non-captive stepper motor. Three parameters, i.e., extrusion speed, material viscosity, and nozzle size, are examined to find the optimum filament production. The extrusion speed was controlled by programming the frequency step of the motor, and the viscosity was controlled by varying the composition of the aquadest-gelatine mixture. The results showed that the stable operation and the best filament were obtained with a motor speed of 0.17 mm/s, the aquadest-gelatine composition of 10 mL aquadest and 3 grams of gelatine powder, and a nozzle diameter of 0.3 mm.

Abstract: New trend in material engineering are composites with biological-based fillers. On of aim in biological-bases composite is how to use waste from agriculture production i.e. unused secondary products known as residues. The aim of this research is experimental investigation of wear resistance of bio-polymer composite reinforce by cotton post-harvest line residues. These residues come from cotton production as a waste which contain cotton stems and plant roots. Most of these residues are burned as energy source, but residues can find other utilization. Composites based on polymer can solve friction and wear problems in industry for their advantages as self-lubrication, light weight, easy of properties modification, etc. This research is part of wide study dealing with material utilization of post-harvest line residues. Mass loss of wear resistance at composite PCFC 500 with short fibres decrease against the matrix up to 21% on 19.28 mg.