Muhammad Arshad and Aman Ullah.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
Synthetic fiber reinforced polymer composites are important commercial materials with diverse applications. Recently, due to strong emphasis on environmental awareness worldwide, utilization of natural fibers in composites has been growing. Natural fibers offer many advantages over synthetic fibers in terms of low density, high toughness, biodegradability, reduced dermal and reduced respiratory irritation, and low cost. However, natural fibers have intrinsic weaknesses such as moisture sensitivity, low thermal stability, low fiber-matrix adhesion, high flammability, sensitivity to radiations, and generally inferior mechanical properties. Exploitation of nanotechnology, incorporation of nanostructures into biofibers, has great potential to address these challenges. The current study includes the nano-modification of protein-based biofibers by grafting POSS nanocages and exfoliation/intercalation of nanoclay respectively to -develop nano-engineered surface modified and wet extruded hybrid fibers. The grafting of nano-POSS on the surface of fibers was investigated and confirmed by the Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). While the presence and dispersion of nanoclay in the hybrid fibers was confirmed by fourier transform infrared (ATR-FTIR), X-ray diffraction (XRD) and TEM. The nano-modifications led to improvements in the properties of all modified fibres, including enhanced thermal stability and improved moisture resistance compared to neat fibers. A new monomer was synthesized from renewable resource and copolymerized with styrene to develop a biopolymer matrix. The modified fibres were further blended with co-polymer matrix to prepare the hybrid biocomposites. The properties of prepared biocomposites were investigated by the dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and SEM. Flammability tests were conducted to investigate the effects of nano-reinforcements on overall fire retardancy of the composites. The results strongly supported the overall improvements in fiber-matrix adhesion, thermal stability, mechanical strength and flame retardancy of nano-modified fiber composites compared to the neat fiber.