Effect of stereoisomerism of the regularly alternating isoprene-propylene copolymer on its thermodynamic properties☆

The methods of vacuum adiabatic and isothermal calorimetry have revealed the influence of the cis- and trans- isomerism of the regurally alternating isoprene-propylene copolymer on its thermodynamic properties and the thermodynamic parameters of synthesis for the region 0–330 K. The glass transition points of the isomers differ by 29 K and the upper limiting temperatures of their synthesis by 190 K. It is shown that over the whole temperature region studied the process of obtaining both isomers and also the process of conversion of the trans- to cis-isomer are thermodynamically permitted.