| Summary: | 碩士 === 國立臺北科技大學 === 有機高分子研究所 === 101 === In this study, polyurethane(PU) was prepared using pre-polymer method with poly(tetramethylene oxide)(PTMO,MW1000) and 4,4-(diphenylmethane diissocyanate)(MDI) as starting materials and 1,4-butanediol as the chain-extender.
The modified PU was synthesized by adding N-BOC-serinol, during the chain extension process, and the product was de-protected the BOC groups of the incorporated N-BOC-serinol units. The pristine multi-walled carbon nanotubes (MWNTs) were air-oxidized at 570℃ to remove carbonaceous particles , sonificated with HF and HNO3 at room temperature to remove metal catalysts , and oxidized with
H2SO4/ HNO3( 3:1 by volume) in order to obtain the acidified-MWNTs(AMWNTs).
The MWNTs possessing COCl functional groups(ClMWNTs) were prepared by refluxing AMWNTs with SOCl2. The modified PU, ClMWNTs, and 4-dimethylaminopyridine (DMAP) were mixed and electrospun into web. The web was then heated in vacuum at 70℃ for 24h in order to get the chemically bonded composite.
PU and MWNTs/PU were characterized by 1H NMR and FTIR which demonstrated that ClMWNTs bonded to the modified PU. The structure of the web was investigated by SEM, and the average fiber diameter was about 400 nm. The TEM images showed most of the MWNTs inside the composite oriented along the axis of the nanofibers. The 5% weight loss temperature(Td) and the glass transition temperature measured by TGA and DMA, separately, increased with increasing MWNTs content of the composite. The surface electric resistivity reduced by increasing MWNTs content of the composite. The mechanical property data showed that the incorporation of MWNTs into composite would caus the increase in the ultimate tensile strength and the Young’s modulus, and result in the decrease of the elongation at break of the material.
Biocompatibilities were measured by the whole blood clotting tests and the cell viability tests (MTT tests). The results showed that the anticoagulation ability of MWNTs/PU was better than those of PU and modified PU, and with the more MWNTs inside the composite ,the less is the blood aggregation. The MTT tests indicated that PU, the modified PU and the MWNTs/PU composite were non-toxic to cells.
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