Rl. Scherrenberg et al., STRUCTURAL ASPECTS OF SUSPENSION POLY(VINYL CHLORIDE) - INFLUENCE OF TEMPERATURE ON THE MACROSTRUCTURE AND MICROSTRUCTURE, Journal of polymer science. Part B, Polymer physics, 32(1), 1994, pp. 99-109
The structural aspects of rigid suspension poly (vinyl chloride), PVC,
have been investigated on the basis of two independent series of susp
ension PVC samples, polymerized at temperatures between 26 and 84-degr
ees-C. The reproducibility of the suspension polymerization process an
d the importance of the polymerization temperature with respect to the
macro- and microstructure is demonstrated. Quantitative examination o
f the grain structure by small angle neutron scattering, Brunauer-Emme
tt-Teller absorption technique, and mercury porosimetry clarifies the
gradual increase of the specific surface on lowering the polymerizatio
n temperature. A detailed WAXS study shows an increasing degree of cry
stallinity on lowering the polymerization temperature, which can be as
sociated with the corresponding increase of the syndiotacticity. Furth
ermore, the presence of a polymerization history in the PVC powders wi
th respect to the crystallinity is evidenced. This effect seems to be
related to chain mobility restrictions during the polymerization proce
ss and is determined by the difference between the polymerization temp
erature and the glass-transition temperature (T(g)) of rigid PVC. This
so-called T(g) effect is indicative of the fact that no appreciable s
welling of PVC by its monomer occurs. (C) 1994 John Wiley & Sons, Inc.