Thermal Analysis of Polymeric Materials and Rubbers

Abstract

This article summarizes the basic principles of differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC) as well as the application of these techniques to polymeric materials or rubbers (elastomers). The determination of glass transition temperature T_g and the heat capacity difference ΔC_p at T_g is crucial to elucidate the amorphous structure of polymers and polymer blends when using thermal analysis. In addition, enthalpy relaxation and thermal history must be considered in order to determine these thermal properties. In particular, TMDSC is a powerful technique to obtain highly sensitive and valuable information about the amorphous structure of polymers. The volume V_α of the cooperatively rearranging region of chloroprene rubbers was determined as a function of crystallinity using TMDSC. Based on the findings that the V_α decreases with increasing crystallinity, the amorphous region of chloroprene rubbers is suggested to be restrained by the cross-link of the crystal.