Heat of mixing of polybutadiene and benzene

Abstract

Meas urements have been made of the heat of mixing of polybutadiene and benzene at 26.9° C by means of a Bunsen-type calorimeter, in which diphenyl ether is the calorimetric medium. The results of these measurements can be represented by t he empirical equation t:;HM = 12 .0vj v2, where t:;HM is heat of mixing in joules per cm3, and VI and V2 are volume fraction s of sol vc n t and polymer, respectively. The data have been combined with previously r eported data on the activity of the solvent in this system to obtain values of t:;SJ, t he partial molal entropy of dilution. The curve of t:;S dRv~ versus V2 for this system lies above the calculatcd curve of t:;sN Rvt where t:;si is the "configurational entropy" of dilution, and also lies above the corresponding exp erime ntal curves for several other polymer-solvent systems.