Based on Hermans and Weidinger postulate that the crystalline fraction is proportional to crystalline intensity Ic and that the amorphous fraction is proportional to amorphous intensity Ia

it is. Suggseteet that for PBT/PET blends we assume that the intensity at 18. 2° is completely originated from amorphous scattering. The separation between the peaks at 17. 2° and 20. 8° is 3. 6°m

which is regarded as large enough to justify this assumption. Thus

it is possible to draw an acceptable demaraction line between the crystalline and amorphous scattering. The degree of crystallinity Xc is given by Xc-Ic/(Ic+KIa)

coefficient K is available by the values of Ic plotted against the values of Ia.For PBT/PET blends

we obtain that K is 0.95 and that correlation coefficient is 0.92 According to the method revieved above

we investi-gated the crystallinity of PBT/PET blends prepared by different ways.