There are two kinds of methods to measure the crystallinity of polymers by WAXD-the relative method (CCI

ICI) and the absolute method (HWM

CPRM

Ruland-M). The results of various methods in the literature are often different. Results of WAXD also disagree with those of other methods (p

DSC

NMR FT-IR etc.). The present work investigated systematically on the differences between WAXD and DSC

p

the choice of 2θ range

the effects of various corrections

the separation of amorphous scattering and the comp arison between the relative method and the absolute methods etc. It is concluded that WAXD is better than DSC and σ

the absolute methods are better than the relative methods and each absolute method has its advantage and shortage. The key problem still isthe separation of amorphous scattering from the total scattering.