Preparation and characterization of starch/EVA composite foams with surface modified kaolin.

Starch/EVA (ethylene-vinyl acetate copolymer)/modified kaolin nanocomposite foaming materials were prepared. The modified kaolin was obtained by γ-methylacryloyl oxypropyl trimethoxysilane (silane coupling agent KH-570) as the nucleating agent. The effects of the modified kaolin were analyzed by activation index, and the structure was characterized by Fourier transform infrared (FT-IR) and SEM. The effects of modified kaolin on the mechanical properties and the cellular structure of the composite foams were also studied. According to the results, when 1.8 phr (parts per hundert parts of resin) silane coupling agent KH-570 modified kaolin, the activation index was 100%. It was found that the modified kaolin played an important role in the formation of the microstructure and the mechanical properties of the composites foams. Modified kaolin could increase the amount of the cells and reduce cell size significantly. The optimum tearing strength of the composite foams was 12.78 kg/cm with 20 phr modified kaolin added. The results were attributed to the nucleation effect of the modified kaolin particles, the high melt viscosity and the complex interface interactions between EVA chains and kaolin particles. [ABSTRACT FROM AUTHOR]