Development of hydroxyapatite nanoparticles reinforced chlorinated acrylonitrile butadiene rubber/chlorinated ethylene propylene diene monomer rubber blends

Hydroxyapatite nanoparticles (HA) reinforced polymer blend based on chlorinated nitrile rubber (Cl-NBR) and chlorinated ethylene propylene diene monomer rubber (Cl-EPDM) were prepared. Resulting blend composites were analyzed with regard to their rheometric processing, crystallinity, glass transition temperature (T_g), mechanical properties, oil resistance, AC conductivity, and transport behavior. The decrease in optimum cure time with the addition of HA is more advantageous for the development of products from these blend nanocomposites. The XRD, FTIR, and SEM confirmed the attachment and uniform dispersion of HA nanoparticles in the Cl-NBR/Cl-EPDM blend. The good compatibility between polymer blend and nanoparticles was also deduced by the formation of spherically shaped HA particles in the blend matrix determined by TEM analysis. DSC analysis showed an increase in T_g of the blend with the filler loading. The addition of HA particles to the blend produced a remarkable increase in tensile and tear strength, hardness, AC conductivity, abrasion, and oil resistance. The diffusion of blend composites was decreased with an increase in penetrant size. The diffusion mechanism was found to follow an anomalous trend. Among the blend composites, the sample with 7 phr of HA not only showed good oil and solvent resistance but also a remarkable increase in AC conductivity and mechanical properties.     

Thermal stability,surface wettability and mechanical behavior of highly ordered ZnO-doped thermoplastic polyurethane films with hierarchically porous structures

In this paper, the effect of ZnO nanoparticle on thermal, microstructure, mechanical behavior, superhydrophobicity of thermoplastic polyurethane (TPU), ZnO/TPU composite materials with doped-ZnO nanoparticles were obtained via a solution blending method. The results show that the melting temperature region in soft segments of ZnO/TPU composite materials was the transition temperature region. The added ZnO slightly enhances the crystalline slipped of ZnO/TPU composite materials, and effectively hinder the transfer of high temperature small gas molecules. Due to the added ZnO nanoparticles, the microphase separation and ordered structures in TPU are reduced. In TPU, and between TPU and ZnO nanoparticles, there are variations in electron density at hard phase and soft phase interfaces. The good ZnO/TPU composites exhibit high water repellence with water contact angle of ~157°. The prepared ZnO/TPU nanocomposites show mechanical properties that are superior to those of pristine TPU. Tensile strength and storage modulus increase by 47.1% and 39.8% at ZnO loading values of 10 wt%. The results indicate that thermal behavior, microstructure, superhydrophobicity and the mechanical behavior of TPU composite materials can be enhanced by the doped ZnO.