Long-Term Durability of Polymeric Matrix Compositespresents a comprehensive knowledge-set of matrix, fiber and interphase behavior under long-term aging conditions, theoretical modeling and ...experimental methods. This book covers long-term constituent behavior, predictive methodologies, experimental validation and design practice. Readers will also find a discussion of various applications, including aging air craft structures, aging civil infrastructure, in addition to engines and high temperature applications.
Sansevieria trifasciata fibre (STF) is a lignocellulosic material which could be utilised for reinforcement composites. Surface modification is often needed to improve the compatibility of ...hydrophilic STF and hydrophobic resin. In this study, treatments for natural fibres to attain superhydrophobic properties were carried out using silica nanoparticles and fluorosilane. Sansevieria trifasciata fibres (STF) were subjected to treatment by deposition of silica (SiOsub.2) nanoparticles which were prepared by the sol-gel method, then followed by modification with fluorosilane, namely 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PFOTS). The presence of SiOsub.2 nanoparticles and PFOTS were evaluated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). The crystallisation properties and thermal behaviour of STF were studied through X-ray diffraction (XRD) and thermogravimetric (TGA) analysis, respectively. The hydrophobicity of STF was determined by water contact angle (WCA) measurement. The results show that nanoscale SiOsub.2 particles were deposited on the STF surface, and PFOTS were covalently linked to them. The SiOsub.2 nanoparticles provide surface roughness to the fibres, whereas the long-chain fluorine on PFOTS lowered the surface free energy, and their combination in these treatments has successfully modified the STF surface from hydrophilic into superhydrophobic with a WCA of 150° and sliding angle of less than 10°. Altogether, a non-toxic, simple, and promising method of imparting hydrophobicity on natural fibres was developed, opening new opportunities for these fibres as reinforcement for composite parts.
Syzgium cumini (L.) Skeels powder (S. cumini powder), also known as Jamun, is well-known for its various medical and health benefits. It is especially recognized for its antidiabetic and antioxidant ...properties. Thus, S. cumini powder is used in various industries, such as the food and cosmetic industries. In this work, the fruit of S. cumini was utilized; its seeds were extracted, dried, and ground into powder. The ground powders were subjected to various techniques such as physicochemical tests, Fourier transform infrared (FTIR) spectroscopy, X-ray diffractometry (XRD), particle size analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and antioxidant analysis. From the physicochemical tests, it was revealed that the jamun seed filler contained cellulose (43.28%), hemicellulose (19.88%), lignin (23.28%), pectin (12.58%), and wax (0.98%). The FTIR analysis supported these results. For instance, a peak at 2889 cmsup.−1 was observed and associated with CH stretching, typically found in methyl and methylene groups, characteristic of cellulose and hemicellulose structures. The XRD results demonstrated that the crystallinity index of the jamun seed filler was 42.63%. The particle analysis indicated that the mean (average) particle size was 25.34 μm. This observation was ensured with SEM results. The EDX spectrum results showed the elemental composition of the fillers. Regarding thermal degradation, the jamun seed filler had the ability to withstand temperatures of up to 316.5 °C. Furthermore, endothermic and exothermic peaks were observed at 305 °C and 400 °C, respectively. Furthermore, the antioxidant property of the powder displayed a peak scavenging activity of 91.4%. This comprehensive study not only underscores the viability of S. cumini powder as a sustainable and effective particulate filler in polymer composites but also demonstrates its potential to enhance the mechanical properties of composites, thereby offering significant implications for the development of eco-friendly materials in various industrial applications.
•Dominant wurtzite ZnO phase, reduced intensity of TiO2 in PMMA matrix.•Ti-OH peak of TiO2 and metal–oxygen peak of ZnO observed in nanocomposite films.•PMMA exhibits nanopores and enhanced ...wettability by 23% with metallic nanoparticles.•Zn2+ ions increase susceptibility to S. aureus.•Surface modification boosts cell viability, promising for biomedical application.
The poly (methyl methacrylate) (PMMA) nanocomposite films were fabricated using a cost-effective solvent evaporation method. The dominance of the wurtzite Zinc oxide (ZnO) phase was observed, accompanied by a suppression in the phase intensity of anatase titanium dioxide (TiO2) in the PMMA matrix confirmed by the XRD. New peaks appeared at 1651 cm−1 for the Ti-OH of TiO2 and 590 cm−1 for the metal–oxygen vibration of ZnO in the nanocomposite films. SEM micrograph of the TZPMMA resulted in the formation of nanopores with the nanoparticles embedded in the PMMA matrix. The wettability was enhanced by 23 % with the incorporation of metallic nanoparticles. Zinc ions increased antimicrobial susceptibility against S. aureus by 20 % more than E. coli, demonstrating the potential for fighting bacterial infections. The porous surface created by the nanoparticles improved the cell viability of the PMMA. Zebrafish embryo mortality percentage (0.5 %) and cell viability percentage (80 %) against human gingival fibroblasts (hGFs) showed that the incorporation of metal oxides made the PMMA, a potential candidate for biomedical applications.
Fiber reinforced polymer composites are an extremely broad and versatile class of material.Their high strength coupled with lightweight leads to their use wherever structural efficiency is at a ...premium. Applications can be found in aircraft, process plants, sporting goods and military equipment. However they are heterogeneous in construction and antisotropic, which makes making strength prediction extremely difficult especially compared to that of a metal. This book brings together the results of a 12year worldwide failure exercise encompassing 19 theories in a single volume. Each contributor describes their own theory and employs it to solve 14 challenging problems. The accuracy of predictions and the performance of the theories are assessed and recommendations made on the uses of the theories in engineering design.All the necessary information is provided for the methodology to be readily employed for validating and benchmarking new theories as they emerge.Brings together 19 failure theories, with many application examples. Compares the leading failure theories with one another and with experimental data Failure to apply these theories could result in potentially unsafe designs or over design.
Numerical simulation of poly Zambaldi, Edimilson; Magalhaes, Ricardo R; Dias, Matheus C ...
Polymer engineering and science,
12/2022, Letnik:
62, Številka:
12
Journal Article
Recenzirano
The advancement of biodegradable polymer application is increasingly growing through various combinations with other materials. There is a great expectation on how the use of those new materials can ...be expanded not only as a replacement for polymers of fossil origin but also in the replacement of metallic materials. Thus, this work presents the use of numerical simulations as a tool to evaluate and reengineer the application of a biodegradable composite constituted by nanofibrillated cellulose (NFC) and poly(lactic acid) (PLA), in the construction of mechanical components. The academic and industrial interest of this work led to a case study using the finite element analysis (FEA) and the composites produced, where it was evaluated the technical feasibility of replacing a mechanical component constructed with 1060 H12 aluminum alloy.
In this study, blends of cyclo-olefin copolymers (COC) that had different monomer compositions and poly(Acrylonitrile-Butadiene-Styrene) (ABS) were prepared and variations in their morphological, ...rheological, and dynamic mechanical properties were investigated. In the morphological analyses, it was seen that all blends with 50/50% composition had a co-continuous morphology, while droplet-matrix morphology was observed for the other compositions. Melt-state shear modulus and viscosity increased with the addition of ABS for the blends prepared with COC derivatives containing 40% and -68% norbornene content by weight, while there was no significant change in the modulus values of those prepared with the COC derivative containing -76% norbornene by weight. On the contrary to other blends, it was observed that the modulus values decreased with the addition of ABS in the blends prepared with COC with 82% norbornene content. Evaluation of the SEM images and Cole-Cole plots indicated that COC-rich blends were more compatible than the ABS-rich blends in the case COC with lower norbornene content was used in polymer blends, while ABS-rich blends became more compatible with increasing norbornene content of COC.
