| Abstract: | Polyoctadecene-1, as isolated from a Ziegler-type polymerization, was examined by density and refractive index measurements and by differential thermal analysis. Two main transitions were observed, their sharpness suggesting that they are both first-order. Extraction with n-hexane at 25°C. separated the polymer into two almost equal fractions, each showing essentially one of these transitions. Transition temperatures were compared with those of certain other polymers having long n-alkyl side chains. From this comparison, and from the findings of other workers, it was concluded that the polymer of lower transition temperature is atactic polyoctadecene, in which the side chains only participate in crystallization, whereas the polymer of higher transition temperature is tactic polyoctadecene, in which crystallization involves both the main chain and side chains. |
