Copolymerization of styrene with p‐substituted styrenes. An insight into the mechanistic classification of Ziegler‐Natta polymerization

Polymer glass transition temperatures

“…This is typical of the behavior of the polyisoprenes. For these polymers, the crystalline regions will act as inert fillers similar to the case of frozen natural rubber latices (8) where the ice crystals have no effect on the rubber Tg because of the relatively large size of the rubber particles (amorphous regions). By contrast, polymers such as polypropylene, which undergo rapid crystallization on cooling from the melt, will have amorphous regions frequently interrupted by crystallites.…”

Characterization of isomeric elastomers using thermal analysis

“…The values of ACp for NR and IR also lie in a narrow region [8] (0.439 to 0.456 J g-1 K-I). Therefore, Tg is not a good indicator for distinguishing these isomers.…”