A STUDY OF VARIATION OF THERMAL-CONDUCTIVITY OF ELASTOMERS WITH TEMPERATURE

The problem of heat transport through non-conducting elastomers has been studied considering phonons as the chief heat carriers, The predominant scattering processes, in different temperature regions, have been identified on the basis of general structural features and the effect of temperature on these. Relations have been deduced for the dependence of the thermal conductivity lambda on temperature, for these systems. The calculated values of six linear polymers, natural rubber and five different synthetic rubbers, are in excellent agreement with the experimental data in the temperature region 60 K-300 K. This range includes the glass transition temperature, which is also the region of conductivity maximum for these polymers. The variation of lambda with temperature has also been studied for vulkollan using the formalism developed in our earlier work for cross-linked polymers. Also for this, the calculated values show a good agreement with the experimental data. The present study indicates that the polymers having similar structures show identical variation trends for lambda vs. T. It also reveals that the structural transitions are clearly reflected in the variation trends of lambda vs. T.