(118d) Hydrogen Bonded Thermal Highways Driving Heat Conduction in Polymer and Polymer Blends Films

Mehra, N., The University of Akron
Zhu, J., The University of Akron
The fundamental factors driving thermal conduction in neat polymers is significantly less explored. Though most work is available in thermally conductive filler-polymer composite, clear understanding of the heat conduction mechanism in polymers without adding inorganic/metallic filler is a subject of great investigation especially for the promotion and development of advanced thermal management technologies. This study shows an interesting tale of intermolecular interaction in governing thermal conduction in polymers. Here by engineering intermolecular interaction in polymer chains a significant enhancement in thermal conductivity was achieved and similarly decrement was observed by breaking interactions. Thermal conductivity of free standing PVA films with different molecular weights and its blends with PEG and PVP was investigated. Effect of the absorption of vapor molecules of water, ethanol, methanol and ethylene diamine on polymer film’s thermal conductivity was studied. Penetration of water molecule in films was found to drastically alter inter-molecular interaction contributing to remarkable 250 % increment in thermal conductivity. The thermal conductivity of PVA films and its blends as a function of moisture content, molecular weight and drying temperature was studied. Films with lower molecular weight had higher thermal conductivity due to less hindered polymer chains and ease of interaction to form continuous thermal highways for phonon transport. This study unveils some of the important yet fascinating drivers of thermal conductivity in polymers & polymer blends which can pave the way for development and fabrication of polymer based materials for thermal management applications.