| Abstract: | The dynamic Young moduli of purified PVC and PVC derivatives were measured at room temperature during the course of irradiation by ultraviolet light at 2537 A. wave-length. The PVC derivatives with copper salicylate, ferrocene, or copper phthalocyanine were prepared by Friedel-Crafts reaction as described in the previous paper. The loss tangent decreased monotonically with irradiation time, while the dynamic modulus appeared to pass through a maximum. More pronounced variations in both E and tan 6 were observed for the PVC derivatives than for the purified PVC, owing to enhanced crosslinking and scission in the presence of the substituents. The gel permeation chromatograms of irradiated PVC samples have been observed to skew to the left, where low molecular weight material occurs. The decrease in E after long exposure was discussed in terms of molecular polydispersity of the soluble fractions of PVC. |
