Thermal properties of isotactic polypropylene quenched from the melt and annealed

DSC investigations on isotactic polypropylene (it‐PP) quenched from the melt and annealed over a range of temperatures are reported. The results confirm the existence of saturation levels of the ordered phase for different annealing temperatures, previously revealed by X‐ray diffraction methods. Thermal, X‐ray diffraction, and density data are correlated in terms of the extent of the ordered phase present in the it‐PP.