Kinetics of Conformational Transitions in Polymers Containing Skeletal Double Bonds

Multidimensional Kramers rate theory is employed to examine the influence exerted by double bonds on the kinetics of conformational transitions of single bonds in trans-polybutadiene and poly(transpropenylene). For both molecules, a detailed discussion of the geometric and potential energy factors that determine the transition rates of the various types of single bonds is presented. Single bonds having nextnearest-neighbor double bonds are found to have mean transition rates half an order of magnitude smaller than that of a polymethylene-like molecule. Single bonds attached to double bonds are predicted to experience up to an order of magnitude enhancement in mean transition rate vis-&-vis polymethylene. Thus, it is concluded that double bonds through their modification of the torsional potential energy surface can produce important effecta on the mechanism and rates of single-bond conformational transitions.