Investigation of the molecular weight and molecular weight distribution of polypropylene macromonomers by size-exclusion liquid chromatography

Анотація

By varying the degradation temperature and pressure, the average molecular weight (MW) of polypropylene macromonomers (PPMM) was regulated. The obtained liquid product was subjected to repeated vacuum distillation, resulting in a narrow fraction of polypropylene macromonomer. The molecular weight (MW) and molecular weight distribution (MWD) parameters of the synthesized PPMM and its copolymers were determined by size-exclusion liquid chromatography (SELC) using a high-performance liquid chromatograph manufactured by Kovo (Czech Republic) equipped with a refractive index detector. Two columns (3.3 × 150 mm) packed with Separon-SGX stationary phase (particle size 7 μm, pore size 100 Å) were used. Dimethylformamide served as the eluent at a flow rate of 0.3 mL/min and a temperature of 20–25°C.