An Infrared Study of the Crystallization of Polyethylene

Abstract

The melting point, temperature for the onset of crystallization, and the isothermal rate of crystallization of polyethylene all decrease on increasing the extent of branching of the polymer chains. In the molecular weight range studied the melting point is independent of the molecular weight. The temperature for the onset of crystallization at any given rate of cooling appears to increase as the molecular weight is decreased. The isothermal rate of crystallization becomes much greater as the crystallization temperature is lowered, however, at a given temperature the rate is affected only slightly by a change in molecular weight and is primarily a function of the degree of branching.