A novel method of hyperbranched poly(amide‐ester) modifying nano‐SiO 2 and study of mechanical properties of PVC/nano‐SiO 2 composites

A new method of surface chemical modification of nano‐SiO 2 was proposed in the paper. In the presence of catalyst, the active hydroxyl groups on the surface of nano‐SiO 2 reacted with AB 2 ‐type monomer ( N , N ‐dihydroxyethyl‐3‐amino methyl propionate) by one‐step polycondensation. And the product's Fourier transform infrared graphs and transmission electron microscopy (TEM) images proved that hyperbranched poly(amine‐ester) (HPAE) was grafted from nano‐SiO 2 surface successfully. Moreover, polyvinyl chloride (PVC)/modified nano‐SiO 2 composites were made by melt‐blending. The composites' structures and mechanical properties were characterized by TEM, scanning electron microscopy, and electronic universal testing machine. The results showed that nano‐SiO 2 grafted by HPAE increased obviously in dispersion in PVC matrix, and mechanical properties of PVC were effectively improved. Additionally, it was found that mechanical properties of PVC/nano‐SiO 2 composites reached the best when weight percent of nano‐SiO 2 in PVC matrix was 1%. Compared with crude PVC, the tensile strength of HPAE grafted nano‐SiO 2 /PVC composite increased by 24.68% and its break elongation, flexural strength, and impact strength increased by 15.73, 4.07, and 184.84%, respectively. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers