In recent years, researchers and scientists are facing problems in terms of environmental imbalance and global warming owing to numerous use of composite materials prepared by synthetic fibers and petrochemical polymers. Hence, an increasing attention has been devoted to the research and development of polymer composites reinforced with the natural fibers. The natural fibers are the most suitable alternative of synthetic fibers due to their biodegradability, eco-friendliness and acceptable mechanical properties. The natural fibers are attracting the researchers and scientists to exploit their properties by amalgamating them with the polymer. The properties of natural fiber reinforced polymer composites mainly depend upon various factors such as properties of fibers and matrices, fiber loading percentage, size and orientation of fibers, stacking sequences, degree of interfacial bonding, fiber surface treatments, hybridization and incorporation of additives and coupling agents. Tensile and flexural tests are the most important investigations to predict the applications of the materials. A good number of research has been carried out on tensile and flexural properties of natural fiber reinforced polymer composites. In this paper, a review on tensile and flexural properties of natural fiber reinforced polymer composites in terms of effects of fiber weight fraction, geometry, surface treatments, orientations and hybridization is presented. Moreover, recent applications of natural fiber reinforced polymer composites are also presented in this study.
The outgassing behavior and mechanical properties of polysiloxane based and phosphorus doped silicate based films as planarization candidates for device processing were evaluated using various analytical techniques. After curing between 370 °C and 450 °C, a high temperature rebake above 410 °C caused twice the weight loss in polysiloxane based films as in silicate films. This means that further outgassing, which could occur to a greater degree from polysiloxane than from silicate, could lead to a more probable blistering within the interlayer of the sandwiched spin-on-glass (SOG) during subsequent thermal processing. However, a well-cured polysiloxane would be a better candidate for planarization applications because the film was found to absorb less moisture and had lower stress than the silicate. Due to high silanol content and high porosity in silicate, it was found to absorb six times more water than polysiloxane. When water evolved, significantly higher stress levels were observed in silicate than in polysiloxane during thermal cycle tests. Infrared spectroscopic analysis revealed that polysiloxane contained Si–O–CH3 moiety, which rendered the film flexible, while silicate contained near-stoichiometric SiO2 bonds, which made for a more rigid and dense structure. This difference in the film structures translated to three times higher stress in silicate than in polysiloxane. During device processing, it was seen that silicate films were more prone to cracking than polysiloxane films. The components of the outgassing materials were either volatile organic species from residual solvents not completely burned out during cure, or carbon dioxide and water vapor as by-products from further cure. Gas chromatography indicated that both types of films contained volatile organic residues when cured at 370 °C. However, at 410 °C, volatile organic species were present in the polysiloxane but not in the silicate. A 30 to 60 min cure at temperature greater than 410 °C was then found to adequately cure polysiloxane. It was concluded that a “well cured” polysiloxane based spin-on-glass (SOG) would be more suitable than a silicate based SOG for planarization application.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.