Comparison of rheological, mechanical, electrical properties of HDPE filled with BaTiO3 with different polar surface tension

In this work, three types of coupling agents: isopropyl trioleic titanate (NDZ105), vinyltriethoxysilane (SG-Si151), 3-aminopropyltriethoxysilane (KH550) were applied to modify the surface tension of Barium titanate (BaTiO3) particles. The Fourier transform infrared (FT-IR) spectra confirm the chemical adherence of coupling agents to the particle surface. The long hydrocarbon chains in NDZ105 can cover the particle surface and reduce the polar surface tension of BaTiO3 from 37.53 mJ/m(2) to 7.51 mJ/m(2), turning it from hydrophilic to oleophilic properties. The short and non-polar vinyl groups in SG-Si151 does not influence the surface tension of BaTiO3, but make BaTiO3 have both hydrophilic and oleophilic properties. The polar amino in KH550 can keep BaTiO3 still with hydrophilic properties. It is found that SG-Si151 modified BaTiO3 has the lowest interaction with HDPE matrix, lowering the storage modulus of HDPE composites to the greatest extent. As for mechanical properties, the polar amino groups in KH550 on BaTiO3 surface can improve the adhesion of BaTiO3 with HDPE matrix, which increases the elongation at break of HDPE composites to the greatest extent. In terms of electrical properties, the polar amino groups on surface of BaTiO3 can boost the dielectric properties of HDPE/BaTiO3 composites and decrease the volume resistivity of HDPE/BaTiO3 composites. The aim of this study is to investigate how functional groups affect the rheological, mechanical and electrical properties of HDPE composites and to select a coupling agent to produce HDPE/BaTiO3 composites with low dielectric loss, high dielectric constant and elongation at break. (C) 2015 Elsevier B.V. All rights reserved.