Mechanism and Stereochemistry in the Anionic Polymerization of 1,3-Cyclohexadiene and the Diimide Hydrogenation of Polymers,

Two polymers with entirely hydrocarbon structures were prepared and characterized for the purpose of preparing low density, hydrolytically-stable plastics with high stiffness and softening-point temperature for evaluation in undersea applications in structural members or syntactic foams. These polymers were prepared by the anionic polymerization of 1,3-cyclohexadiene to polycyclohexadiene, which was the first candidate material, followed by hydrogenation of this polymer to polycyclohexane, the second candidate material. The limitation in applications of these materials as plastics was the inability to prepare the first polymer in high modecular weight. The molecular weight limitation in the anionic polymerization of 1,3-cyclohexadiene was found to be caused by a degradative chain transfer reaction to monomer forming benzene as a by-product. Polycyclohexane was prepared from polycyclohexadiene without degradation by a homogeneous hydrogenation reaction with diimide, which was formed in place by the thermal decomposition of p-toluenesulfonylhydrazide. Author