Study on structure -induced heat transfer capabilities of waterborne polyurethane membranes

Structural induced heat transfer capability of waterborne polyurethane (WPU) membrane was investigated. Hereby, WPU emulsions were synthesized with series of combinations of 2,4-Diisocyanatotoluene (TDI), poly(propylene glycol) (PPG), Poly(ethylene glycol) (PEG), dimethylolpropionic acid (DMPA) and ethylene glycol (EG) for studied membranes preparation. In this study, optimal prepolymer components, hard segment content, hydrophilic fragments and thermal annealing treatment on membrane-forming process were performed to study the structural features of WPU and corresponding heat conduction. Regarding to the results of AFM, XRD and DSC analysis, we found heat conduction was tightly related to the status of phase behaviors in studied WPU membranes. That's because phonon propagation as one primary heat carrier in polymer matrix was closely depended on the morphology of polymer chains. Good phase separation behavior could conduce to form long-range, short-range and microcrystalline ordering in WPU through intermolecular force (e.g. hydrogen bond), further pave as a conductive path for heat transmitting.