| Summary: | 碩士 === 國立成功大學 === 化學工程研究所 === 83 === A series of polyurethane polymers based on hydroxy-terminated
polydimethylsiloxane soft segments of molecular weight 1800
were synthesized . The hard segments consisted of
4,4'-Diphenylmethane diisocyanate (MDI) which was chain
extended with dimethylolpropio nic acid (DMPA) and bis(2-
hydroxy) ester terephthalic acid (BHET) . The anionomers was
ionized by using sodium hydroxide . The stru cture of
polyurethanes was characterized using Fourier transform
infrared (FTIR) spectrophotometer . By using differential scann
ing calorimeter (DSC) measured the thermal transition of poly
urethanes and by Instron for mechanical property . The data of
viscometer indicated that the intrinsic viscosity increased as
the content of DMPA increased while the solution contains no
salt . Static light scattering showed the radius of gyration
decreased as the content of DMPA increased . Weight-averag
molecular weight showed the same tendency . DSC indicated that
the content of BHET increased , the glass transi- tion
temperature raised , too . Instron analysis showed that the
more BHET in hard segment , the more increase in the Young's
modulus and ultimate tensile strength and decreased in ultimate
elongation .
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