Thermal degradation behavior of thermoplastic polyurethanes based on polycarbonate-diol: Effect of the hard and soft segment content in the PU
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초록
내용
Waterborne polyurethane dispersions (PUDs) were synthesized using 4,4′-methylenebis(cyclohexyl isocyanate), dimethylol propionic acid, and three different polycarbonate-diols whose molecular weight were 495, 1085, and 2028, respectively. 1,4-butanediol and ethylene diamine were used as chain extender. The molecular structure and size of the PUDs were mainly modulated with the chain length of the polycarbonate-diols, the NCO index (isocyanate equivalents/hydroxy equivalents), and the type of chain extender. By varying the molecular weight and composition of PC-diols, we prepared the various PUDs. The molecular sizes and chemical compositions of the PUD were determined using wet chemistry methods, FT-IR technique, and DLS size measurements. The amount and kind of hard- and soft-segment, the initial decomposition temperature, thermal stability, and decomposition kinetics of the PUD were identified using TGA and DSC.