Abstract: In this paper, the graft copolymer LDPE-g-MAH/St was prepared with LDPE, monomers of styrene and malefic anhydride via free radical polymerization. The copolymer was characterized by IR. Then the crystal morphology of copolymer was investigated by polarizing microscope. Differential scanning calorimetry (DSC) was used to analyze their isothermal and non-isothermal crystallization behavior. In the isothermal crystallization process, the crystallization temperature was set in 92、93、94 and 95 ° c. The Avrami equation and Hoffman theory was used to analysis LDPE and LDPE-g-MAH/St, then obtained parameters of Avrami equation——n, K (T), t1 / 2 (T).In the case of non-isothermal crystallization, the cooling rate was set in 5, 10, 15, 30 ° c/min respectively. It was found that the Ozawa analysis was rather inapplicable for the copolymer. In contrast, the modified Avrami method, as well as the method proposed by Mo was applied giving satisfactory results.
Keywords:LDPE; MAH; St; Graft copolymer; Crystallization kinetics