6533b873fe1ef96bd12d4bec

RESEARCH PRODUCT

false

Radulf C. OberthürRudolf G. KristeSigrid Schmitt‐streckerBurghard J. SchmittJernej Jelenič

subject

chemistry.chemical_classificationExothermic reactionPolyvinyl chloridechemistry.chemical_compoundchemistrySpinodal decompositionPolymer chemistryPolymer blendPolymerEntropy of mixingNeutron scatteringMiscibility

description

Provided a polymer is soluble, i. e., molecularly dispersed in another polymer irrespective of the molecular weight of the components, the solution is exothermic. By increasing the temperature two effects, both unfavourable to mixing become larger: (i) the excess entropy of mixing caused by contact interaction and (ii) the total effect from the difference of the free volumes of the pure components. So, an upper miscibility gap occurs. The thermodynamic properties of the mixture cannot be derived from the properties of the pure components. They can be described by the corresponding states theory of Prigogine, Flory, and Patterson with suitable values for the contact energy and contact entropy parameters X12 and Q12. The temperature of separation can be predicted from measurements on the mixture at low temperatures.

https://doi.org/10.1002/macp.1984.021850113