Abstract:

A working curve was established for the determination of ethylene content of random and impact copolymerized polypropylene using an analysis methods provided by foreign investors and a series of standard samples. Owing to the instability and heterogeneity in structure and properties of polypropylene powder samples， the ethylene content of actual powder samples is often not completely consistent with the establishment of marking treatment. By selecting different grades of ethylene?propylene copolymer?type polypropylene powder samples， the effects of cooling mode， antioxidant， and particle size of samples on the determination result of ethylene content in hot?pressing sampling were analyzed. The results indicated that the cooling mode generate an obvious effect on the determination of ethylene content in powders during the hot?pressing process. Similarly， there was a significant influence on the determination results resulting from the powder samples with or without antioxidant as well as the antioxidant types. In addition， the particle size of powder samples generated a great effect on the determination results of ethylene content.

Key words: polypropylene, ethylene content, powder, effect