Melting and internal motion in highly alternating copolymers of ethylene and carbon monoxide

The melting point of the 1:1 copolymer of ethylene and CO is 244°C. It falls rapidly as the percent CO is reduced indicating that the heat and entropy of fusion are 0.60 kcal and 1.15 e.u./mol of chain atoms, respectively. These are lower than the values for polyethylene. Dynamic mechanical measurements showed loss peaks at −100° and 25°C. The low temperature γ‐relaxation which is also seen in dielectric data appears to be a local mode relaxation with an activation energy of about 12 kcal/mol. The room temperature relaxation is associated with a large decrease in the modulus and a large increase in the dielectric constant. It is probable that the low entropy of fusion is due in part to extensive motion in the crystal.