The effect of silica morphology on properties of PVA/silica nano-composites

Two kinds of poly(vinyl alcohol) (PVA)-silica composites were prepared with different methods. One composite was prepared by directly mixing PVA with 80 nm silica nano-particles which were made from tetraethoxysilane (TEOS). The another was obtained by the mixing PVA and hydrolyzed TEOS in the presence of acid-catalyst. The properties of the two PVA/silica hybrids were characterized by means of scanning electron microscopy (SEM), UV-Visible spectroscopy, solubility tests, limiting oxygen index (LOI) test, tensile test and dynamical mechanical analysis (DMA), respectively. The results indicate that PVA-TEOS composites (PT for short) display more transparency than PVA-silica nano-particles hybrids (PS for short). At the same time, The PT composites presented more excellent performance than PS in water resistance, fire resistance and mechanical properties. Moreover, the T _g of PT increased with increasing TEOS content, while that of PS decreased.