| Summary: | 碩士 === 萬能科技大學 === 材料科技研究所 === 97 === Polyurethanes with water premeability in coating process had a few difficulties; because they were incorporated by the agent of permeability resulted in a lot of decrease on the properties. The polyurethane with moisture permeability that soft segment consisted of the poly(ethylene oxide-co-propylene oxide) (EOPO) and poly (tetramethylene glycol)(PTMG) which were synthesized by two-step method. The viscosity for the polyurethane with water permeability herein were between 27000~38000cps corresponding to general standard for coating resin. The polyurethanes with moisture permeability have two steps of degradation; the first was the hard-segmented degradation between 200 and 340℃ and the second was soft-segmented degradation above 340℃. Although the polyurethane with moisture permeability possessed two types of soft-segment, they only exhibited one soft-segmented glass transition region at below 0℃ due to the method of copolymerization. Similarly, the polyurethane with moisture permeability also display one hard-segmented glass transition region at beyond 25℃, because they hard-segmented content was low below 32wt% resulted in their length of hard-segment was only one to two units. The hard-segmented glass transition region is related to a endothermic behavior (T1) for the short-range ordering of amorphous urethane hard-segment domains. Furthermore, the degree of moisture permeability and water resistant are respectively beyond 3500 g/m224hr and 4300mmH2O.
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