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The present investigation seeks to assess the impact of fillers on the mechanical characteristics of entirely biodegradable composites, introducing an advanced solution to fulfil long-term durability demands within point-of-purchase (POP) industries. The inclusion of calcium carbonate (CaCO3) fillers on the various properties of the flax fibre-reinforced composites, after accelerated irradiation in an ultraviolet (UV) radiation exposure has been investigated in the present study. Different types of flax fibre-reinforced poly lactic acid (PLA) biocomposites (with and without filler) were fabricated. The mechanical (tensile and flexural), and physical properties of the specimens were assessed after 500 h of exposure to accelerated UV irradiation of 0.48 W/m2 at 50 °C and were compared with those of the unexposed specimens. The results indicate that the presence of the inorganic filler significantly improved the performance of the biocomposites compared to the unfilled biocomposites after UV exposure. After adding 20% of fillers, the tensile strength was increased by 2% after UV degradation, whereas the biocomposite without filler lost 18% of its strength after UV exposure. This can be attributed to the change in the photo-degradation of the PLA due to the presence of the CaCO3 filler, which acts as a safeguard against UV light penetration by creating a protective barrier. The scanning electron microscopy (SEM) images of the degraded specimen surface show substantial difference in the surface topography of the composites with and without fillers. [ABSTRACT FROM AUTHOR]

Mechanical properties of Roselle fiber reinforced vinyl ester biocomposite were studied based on the fiber content and length in the present communication. Usually, natural fiber reinforced polymer composites depend on some aspects such as fiber content, fiber length and orientation, the fiber-matrix adhesion. Composite plates were prepared by a simple hand lay-up technique for two different fiber lengths (3 and 13 mm) and five different fiber content (10, 20, 30, 40 and 50 wt%). Composite specimens were tested according to ASTM and ISO standards and their results were recorded. Experimental results showed that mechanical properties such as tensile, flexural and impact, increases with increase of fiber content up to 40 wt% after which it is decreases at both the fiber length. However, modulus values were increased linearly with fiber content of 10 to 50 wt%. Composites with the fiber length of 13 mm show the high level of mechanical properties compared to composites with the fiber length of 3 mm at all combinations of fiber contents. It is observed that the optimal fiber content is 40 wt%, which can be used to obtain the maximum property level in the Roselle fiber reinforced vinyl ester composites. [ABSTRACT FROM AUTHOR]

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

Low-porosity materials based on hot-pressed wood fibers or nanocellulose fibrils (no polymer matrix) represent a new concept for eco-friendly materials with interesting mechanical properties. For the replacement of fossil-based materials, physical properties of wood fiber materials need to be improved. In addition, the carbon footprint and cumulative energy required to produce the material also needs to be reduced compared with fossil-based composites, e.g., glass fiber composites. Lignin-containing fibers and nanofibers are of high yield and special interest for development of more sustainable materials technologies. The present mini-review provides a short analysis of the potential. Different extraction routes of lignin-containing wood fibers are discussed, different processing methods, and the properties of resulting fiber materials. Comparisons are made with analogous lignin-containing nanofiber materials, where mechanical properties and eco-indicators are emphasized. Higher lignin content may promote eco-friendly attributes and improve interfiber or interfibril bonding in fiber materials, for improved mechanical performance. [ABSTRACT FROM AUTHOR]

In recent years the interest in the realization of green wood plastic composites (GWPC) materials has increased due to the necessity of reducing the proliferation of synthetic plastics. In this work, we study a specific class of GWPCs from its synthesis to the characterization of its mechanical properties. These properties are related to the underlying microstructure using both experimental and modeling approaches. Different contents of Miscanthus giganteus fibers, at 5, 10, 20, 30 weight percent's, were thus combined to a microbial matrix, namely poly (3-hydroxybutyrate)-co-poly(3-hydroxyvalerate) (PHBHV). The samples were manufactured by extrusion and injection molding processing. The obtained samples were then characterized by cyclic-tensile tests, pycnometer testing, differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and microscopy. The possible effect of the fabrication process on the fibers size is also checked. In parallel, the measured properties of the biocomposite were also estimated using a Mori–Tanaka approach to derive the effective behavior of the composite. As expected, the addition of reinforcement to the polymer matrix results in composites with higher Young moduli on the one hand, and lower failure strains and tensile strengths on the other hand (tensile modulus was increased by 100% and tensile strength decreased by 23% when reinforced with 30 wt % of Miscanthus fibers). [ABSTRACT FROM AUTHOR]

Over recent years, enthusiasm towards the manufacturing of biopolymers has attracted considerable attention due to the rising concern about depleting resources and worsening pollution. Among the biopolymers available in the world, polylactic acid (PLA) is one of the highest biopolymers produced globally and thus, making it suitable for product commercialisation. Therefore, the effectiveness of natural fibre reinforced PLA composite as an alternative material to substitute the non-renewable petroleum-based materials has been examined by researchers. The type of fibre used in fibre/matrix adhesion is very important because it influences the biocomposites' mechanical properties. Besides that, an outline of the present circumstance of natural fibre-reinforced PLA 3D printing, as well as its functions in 4D printing for applications of stimuli-responsive polymers were also discussed. This research paper aims to present the development and conducted studies on PLA-based natural fibre bio-composites over the last decade. This work reviews recent PLA-derived bio-composite research related to PLA synthesis and biodegradation, its properties, processes, challenges and prospects. [ABSTRACT FROM AUTHOR]

Fused deposition modeling (FDM) is a rapidly growing three-dimensional (3D) printing technology and has great potential in medicine. Polyether-ether-ketone (PEEK) is a biocompatible high-performance polymer, which is suitable to be used as an orthopedic/dental implant material. However, the mechanical properties and biocompatibility of FDM-printed PEEK and its composites are still not clear. In this study, FDM-printed pure PEEK and carbon fiber reinforced PEEK (CFR-PEEK) composite were successfully fabricated by FDM and characterized by mechanical tests. Moreover, the sample surfaces were modified with polishing and sandblasting methods to analyze the influence of surface roughness and topography on general biocompatibility (cytotoxicity) and cell adhesion. The results indicated that the printed CFR-PEEK samples had significantly higher general mechanical strengths than the printed pure PEEK (even though there was no statistical difference in compressive strength). Both PEEK and CFR-PEEK materials showed good biocompatibility with and without surface modification. Cell densities on the "as-printed" PEEK and the CFR-PEEK sample surfaces were significantly higher than on the corresponding polished and sandblasted samples. Therefore, the FDM-printed CFR-PEEK composite with proper mechanical strengths has potential as a biomaterial for bone grafting and tissue engineering applications. [ABSTRACT FROM AUTHOR]