Characterization of polyolefins by differential thermal analysis

Abstract

Abstract Differential thermal analysis has been used to study the solid‐liquid transitions of four polyethylenes, an isotactic polypropylene, a series of ethylene‐propylene copolymers, and a physical mixture of polyethylene and polypropylene. The thermograms obtained directly yield the transition temperatures. By calibration, heats and entropies of fusion were also derived from the thermograms. From the heats of fusion, the degree of crystallinity of these polymers has been calculated. Differential thermal analysis can detect a physical mixture of polymers that melt sufficiently wide apart. The thermogram‐peak areas are proportional to the amounts of material present. Convenience and speed make differential thermal analysis a useful tool for characterizing polymeric materials when uniform conditions are maintained.