Preparation and properties of thermal yellowing resistant polyvinylidene chloride resin

Polyvinylidene chloride (PVDC) resin modified with γ-methylacryloxy propyl trimethoxysilane (KH570) and acrylamide (AM) was prepared by semi-continuous seed emulsion polymerization. The polymerization process and reaction temperature were optimized through conversion rate and oven heat aging test. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analysis showed that KH570 and AM could be successfully grafted into the PVDC resin chain. When the addition amounts of KH570 and AM are 1 wt.% and 1.5 wt.%, respectively, and the reaction temperature is 74 °C, the resin film exhibits significant improvement in yellowing resistance and mechanical properties. The initial yellowing time of the resin film modified by KH570 and AM was 290 min, which was 5.8 times of the unmodified resin film, and the tensile strength can reach 10.81 MPa, which is 1.75 times of the unmodified resin film. Because the modified resin has good thermal yellowing and mechanical properties, it has potential application prospects in food and drug packaging.