Polyurethane (PU) foam is known as the popular material for the applications in many fields of industry and life. To improve the mechanical and thermal properties of this material, in this research, PU foam was reinforced with aniline-modified multiwalled carbon nanotubes (MWCNTs). Fourier transform infrared FTIR spectrum of modified MWCNTs showed the aniline was grafted on the surface of MWCNTs through the appearance of –NH2 stretches. The effect of MWCNTs with and without modification on the density, porosity, compressive strength, and heat conductivity of PU/MWCNT foam nanocomposites was investigated. The dispersibility of MWCNTs in the PU matrix was enhanced after modification with aniline. Compressive strength of PU nanocomposite reached the highest value after adding 3 wt.% of modified MWCNTs into PU foam. Besides, the water uptake of PU nanocomposites using 3 wt.% of MWCNTs was decreased to 13.4% as compared to that using unmodified MWCNTs. The improvement in thermal conductivity of PU/aniline-modified MWCNT nanocomposite was observed due to the change in the cellular size of PU foam in the presence of MWCNTs as shown by SEM images.

Every year, a large amount of waste gypsum, a by-product of fertilizer production, was produced and landfilled that increasing the harm to the environment. In this study, for the purpose of utilizing waste gypsum, it was studied as the filler in blend of high density polyethylene (HDPE) and ethyelene vinyl acetated (EVA) with anti UV additives in order to improve the mechanical strength and lifespan of this composite. After using ethylene bis stearamide (EBS) to modify waste gypsum, modified waste gypsum (mGyp) and anti-UV additives at various contents were dispersed into HDPE/EVA blend by melt-mixing method to obtain HDPE/EVA/mGyp composites. As the results, the color difference and tensile strength of composite using additives did not changed much after 20 cycles of accelerated weathering test. In the presence of anti-UV additives, the photodegradation process was inhibited by showing the low carbonyl index of composite compared with samples without additives. Beside, the structure of composite using anti-UV additives is smooth and without cracks after accelerated weathering test as observed in SEM images. That led to the tensile strength of sample did not change much.