Structure changes in PVC at high temperatures as determined from X-ray diffractometer curves

Abstract

X-ray diffractometer traces obtained from PVC samples maintained at temperatures in the range 180 to 200°C indicate that crystal melting is followed by a state of intermediate order rather than by a truly amorphous state. In addition, this study raises serious doubts regarding the validity of the assumption that the x-ray scattering profile from quenched PVC samples is representative of the amorphous phase. Any crystallinity values derived on the basis of that assumption are therefore open to question.