Influence of Zinc Oxide on Thermoplastic Elastomer-Based Composites: Synthesis, Processing, Structural, and Thermal Characterization

Abstract

It was aimed to investigate how thermal conductivity and stability properties of synthesized thermoplastic elastomers were influenced by zinc oxide (ZnO) additives which differed in size and surface treatment. ZnO particles were prepared by the homogeneous precipitation method by mixing aqueous solutions of hexamethylenetetramine (HMT) and zinc nitrate. The obtained particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Poly(vinyl pyrrolidone) (PVP) was used as a modifier to reduce aggregation among the ZnO particles. The composites, prepared by melt compounding method, were characterized in terms of their morphology and thermal properties. Uniformly distributed surface treated particles caused an enhancement in thermal conductivity properties. At 10 wt% ZnO concentration the thermal conductivity of composite reached 1.7 W/mK compared with 0.3 W/mK for the neat polymer. At the same filler loading, ZnO nanoparticles exhibited a greater effect on thermal conductivity compared with submicron sized particles. It was found that the coefficient of thermal expansion of composites decreased at low temperature (55 degrees C) with increasing ZnO content. Thermal gravimetric analysis (TGA) showed that the neat polymer and the composites were resistant up to 340 degrees C without significant mass loss