Obtaining and characterizing biodegradable composites from agroenergetic residues

The study aimed to produce biodegradable composite materials from sugar cane straw and castor oil-based resin. The fibers were used in two sizes: 0 <fibers ≤4.27mm and 4.27 <fibers <10mm; resin in the proportion of 10%, 15% and 20%. The preparation method was carried out according to NBR 14810-2: 2018, using the compression molding technique at room temperature. Physical assays were carried out: moisture and swelling; mechanical assays: static bending and compression. The morphological assay was evaluated: scanning electron microscopy; and the composite biodegradability assay, over a three-month period. In order to validate the results, the statistic graphic was performed with significance at 5% by the F test, compared to the means by the Scott-knott test of the physical and mechanical treatments. The results showed that the values of the physical assays have met the minimum limits established by the standard, resulting in 8.72% swelling of the composite material. In the mechanical assay, the composite with less fiber and 20% resin was more resistant in the bend test with a capacity of 3.69 N/mm², and in the compression assay with 2.98 N/mm². The morphological analysis showed a wide interaction at the matrix/reinforcement interface. The biodegradation assay showed that over the months the composites started to lose weight, which shows the improvement of the degradation. Therefore, the composite produced has great potential in the market, it is considered biodegradable and of low cost compared to composites produced from synthetic fibers.

Influence of out-of-plane fiber waviness and different environmental conditionings on mechanical and morphological characteristics of fiber glass/epoxy laminates

The use of structural polymeric composites constitutes an interesting option in the area of wind turbine blade manufacturing. Nevertheless, thick composite components may present out-of-plane waviness in their fibers, compromising the service life of the wind blades. In this context, the present study aims to study the influence of out-of-plane waviness in the fibers with different degrees of severity as well as to verify the effect of fiber glass/epoxy resin composites immersion in distilled water and saline solution in their tensile strength (σmax), modulus of elasticity (E), and deformation at break (єrup), analyzing the reinforcement/matrix interface changes. The results showed that the increase in severity promoted, in general, a statistically significant deterioration in σmax of the samples exposed to the same environmental conditioning. The conditioning led to a decrease in E and an increase in єrup, attributed to the deterioration of the interface and the plasticization of the polymeric matrix, respectively, as evidenced by fractographic analysis. The effect of severity on the єrup and σmax properties was only noticed in laminates exposed to environmental conditioning, due to water sorption favoring the deterioration of the matrix/reinforcement interface, intensifying the deleterious effect of out-of-plane waviness of fibers.

Functionality Based Design of Sustainable Bio-Composite

Bio-composites have diverse functional demands for many structural, electrical, electronic, and medical applications. An expansion of the composite functionality is achieved by manipulating the material and design scheme. Smart selection of matrix-reinforcement combinations will lead to applications that have never even been considered. Research holds a huge potential to create a wide variety of usable materials by mixing different fillers and modifying the parameters. Apart from selecting the polymer and the filler, the engineer will have to understand the compatibility of the polymer and the filler, dispersion, and bonding behavior making the design of polymer nanocomposite a rather complex system. In this chapter, we have tried to display different functional materials development pursuit.

New composite materials using polyester woven fabric scraps as reinforcement and thermoplastic matrix

In this study, polypropylene-based thermoformed composites have been obtained using polyester woven fabric scraps as reinforcement. Four types of matrix have been used for the experiments: biaxially oriented polypropylene bag waste (BOPP), polypropylene nonwoven waste (TNT), 50/50 BOPP/TNT waste and virgin polypropylene fibres (PP). The percentage of matrix has been varied at four levels: 20%, 30%, 40%, and 50%. The effect of matrix/reinforcement mass ratio and matrix type on the mechanical properties of composite materials has been studied. Since the composite materials are intended to replace the oriented strand boards (OSB) in construction and furniture applications, comparison with the characteristics of 8 mm OSB has been made.

Microstructure and Corrosion Performance of Aluminium Matrix Composites Reinforced with Refractory High-Entropy Alloy Particulates

Novel aluminium matrix composites reinforced by MoTaNbVW refractory high-entropy alloy (HEA) particulates have been fabricated by powder metallurgy. The microstructure of the produced composites has been studied and the corrosion behaviour assessed in 3.5% NaCl solution. The composites exhibited low porosity, good homogeneity, few defects, and good distribution of the reinforcing phase in the Al matrix. No secondary intermetallic phases have been formed while the interface between matrix/reinforcement showed good bonding with no signs of reactivity. Increasing the volume of the reinforcing phase leads to increased hardness values. Al-HEA composites exhibited susceptibility to localised forms of corrosion in 3.5% NaCl solution. The microstructure has been analysed and corrosion mechanisms have been formulated.

Exploration of cassava clones for the development of biocomposite films

<abstract> <p>Due to the growing interest in developing bioplastic films from renewable sources, the performance of biocomposite films produced of native starch from cassava clones reinforced with cassava bagasse was explored. The biocomposites were prepared from the starch of cassava clones MMEXV5, MMEXV40, and MMEXCH23, reinforced with bagasse at 1%, 5%, and 15%. Their structural, mechanical, and thermal properties were subsequently assessed. When analyzing the starch, differences in the intensities of the Raman spectra exhibit a possible variation in the amylose-amylopectin ratio. In the biocomposites, the bagasse was efficiently incorporated into polymeric matrixes and their thermogravimetric analysis revealed the compatibility of the matrix-reinforcement. The starch films from the MMEXV40 clone showed better tension (2.53 MPa) and elastic modulus (60.49 MPa). The assessed mechanical properties were also affected by bagasse concentration. Because of the above, the MMEXV40 cassava clone showed potential to develop polymeric materials, given its tuberous roots high yield, starch extraction, and good performance in its mechanical properties. At the same time, the starch source (clone) and the bagasse concentration interfere with the final properties of the biocomposites.</p> </abstract>