Glass-transition temperature and microstructure of polybutadienes

DSC and NMR are employed to determine the glass-transition temperatures and the structural features of polybutadienes with widely varying configuration isomeric compositions. The dependences of the glass-transition temperature on the contents of cis-1,4-, trans-1,4, and 1,2-units in polybutadiene chains are plotted and discussed. An analysis of the experimental results and the published data suggests that, in the study of the glass-transition-structure relationship, simplified approaches are inapplicable and it is necessary to consider the configurational and conformational geometry of polybutadiene chains.