Synthesis and Thermal Characterization of Precision Poly(p‐cyclohexylene alkylene)s via Acyclic Diene Metathesis Polycondensation

Abstract

The synthesis and thermal characterization of poly(p‐cyclohexylene alkylene)s (PPCs) is described. Polymers containing 1,4‐cyclohexylene units on every 15th, 19th, and 21st chain carbon are prepared by the acyclic diene metathesis polycondensation of symmetric α,ω‐dienes obtained from the α‐alkylation of cyclohexane‐1,4‐dicarbonitrile. Exhaustive hydrogenation of the unsaturated polymers yields fully cycloaliphatic polymers with excellent resistance to thermal degradation. The thermal analysis of the unsaturated and saturated materials reveals a strong influence of the cis‐alkene and cis‐1,4‐cyclohexylene on the final thermal properties of each material. PPC exhibits higher melting temperature and thermal stability than similar materials, in which the aliphatic ring is replaced by aromatic rings or short chain branches. The melting behavior is discussed in terms of the higher flexibility and enhanced intermolecular packing of the symmetrical 1,4‐cyclohexylene units incorporated within the chain. image