Paper Title
Polyurethane Elastomers with Improved Thermal Conductivity Part I: Elaborating Matrix Material for Thermal Conductive Composites
Abstract
Cross-linked polyurethane elastomer matrix was evaluated for thermal conductive composites with magnesium
oxide powder (MgO). MgO as one of the cheapest materials for high thermal conductivity, seems to be useful for incorporation
in polyurethane elastomer increasing thermal conductivity of the composites. Possible matrix polyurethane elastomers were
fabricated. The effect of MgO contents from 1 to 30 %wt were investigated bothin flexible and in rigid polyurethane
elastomers. First experimental aim is investigating the structure of the polymer intended for application. Improving thermal
conductivity was first not achieved but the causes of the poor results were discovered. After that differential scanning
calorimetry (DSC) and thermally stimulated discharge (TSD) methods were used to examine the structure of polyurethane
elastomers. Furthermore, hardness measurements were carried out for estimating the effect on mechanical properties. Then,
morphology of theMgO particles was observed using scanning electron microscope (SEM). Results showed that thermal
conductivity of the composites both of flexible and rigid polyurethane elastomers did not significantly change with loading
MgO contents less than 30 %wt. In case of structure examinations, DSC thermograms registered a small transition around -62
°C of flexible polyurethane elastomers and their composites while the small transition of rigid polyurethane elastomers were
hard to evaluate because the DSC technique is not sensitive enough for detecting a glass transition in these rigid polyurethane
elastomer chains. Therefore, TSD technique was used to investigate chain relaxation. Pure flexible and rigid polyurethane
elastomers show the same glass transition temperatures of soft segments around -65 °C. The incorporation of MgO less than30
%wt in both flexible and rigid polyurethane elastomer did not significantly affect hardness properties. Moreover, the smallest
MgO particle observed were around 400 nm by SEM technique.
Keywords - Polyurethane Elastomers, Magnesium Oxide, Thermal Conductivity