Heat and entropy of fusion of polypropylene

摘要

AbstractThere are wide discrepancies in the literature values for the heat of fusion (ΔHu) of isotactic polypropylene. A study was therefore made of the variables affecting ΔHuas determined by differential thermal analysis. The results of this study show ΔHufor 100 “crystalline” polypropylene to be 2400 cal./mole repeating unit with 2σ = 300. The entropy of fusion is 5.4 e.u./repeating unit (2σ = 0.3). Thermal history, potential errors in sample–sensor contact as well as uncertainties in x‐ray analysis for per cent crystallinity a