THE EFFECT OF CROSS-LINKING ON THE GLASS-TRANSITION TEMPERATURE AND THE DENSITY OF DIETHYLENE GLYCOL BIS(ALLYLCARBONATE) POLYMER NETWORKS

The effect of crosslinking on the glass transition temperature and the specific volume of poly(diethylene glycol bis(allyl carbonate)) netwo rks was studied using a series of networks with progressively decreasi ng density of crosslinks. The networks were prepared by a bulk copolym erisation of ethylene glycol bis(allyl carbonate) with an increasing a mount of allyl ethoxyethyl carbonate. It was found that their glass tr ansition temperature determined by the Dynamic Mechanical Thermal Anal ysis decreases linearly with increasing concentration of the monoallyl comonomer whilst the increase in their specific volume is non-linear. This is explained by the non-equilibrium state of the networks at the temperature of the specific volume measurement.