Study On The Preparation And Properties Of Polyurethane/carbon Nanotubes Composites

Through step-by-step grafting, multi-carbon nanotubes (MWCNTs) with isophorone diisocyanate (IPDI) has been obtained. Those MWCNT-IPDI is well dispersed in tetrahydrofuran (THF) and make solution much more transparent. Therefore, polyurethane filled with MWCNT-IPDI nanocomposite has good mechanical properties. And because of the similar structure and hydrogen bond between hard segment of PEU and side chain of MWCNT-IPDI, the glass transition temperature in hard segment of this composite has been enhanced obviously. Besides, owing to the well dispersion of MWCNT-IPDI, which makes water vapor easy to getting through the inside and outside nanotubes, the water vapor permeability (WVP) of materials has been greatly increased. And the increase in free volumes and movable chain on MWCNTs also result in the high WVP.Similarly, MWCNTs have been grafted by 3, 3,4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 8-tridecafluoro-l-octanol (TDFOL). Both the tensile strength and elongation of PEU/MWCNT-TDFOL membrane have been enhanced and the storage modulus is increased as well. And the water contact angle of PEU/MWCNT-TDFOL composite has also been increased owing to the migration of the fluorinated chain on MWCNT-TDFOL.Finally, in order to gain a much more hydrophobic PEU material to satisfy the needs of biomaterials, raw MWCNTs,MWCNT-COOH and MWCNT-TDFOL are deposited onto the polyurethane/fluorinated polyurethane (PEU/FPEU) films. Because of the nanostructure and hydrophobic group on MWCNTs, membrane deposited by raw MWCNTs and MWCNT-TDFOL have much higher water contact angle and well blood compatibility. Nevertheless, grafted MWCNTs (MWCNT-COOH and MWCNT-TDFOL) have some interaction with PEU/FPEU in depositing process, which leads to the stable and bio-compatible materials.