Study Of Biostable Polyurethanes Based On Polyhexamethylene Carbonate Diols And IPDI

A series of linear and crosslinked polycarbonate polyurethanes (PCUs) with variation of NCO/OH molar ratio was synthesized by solution two-step polymerization. Polyhexamethylene carbonate diols were used as soft segment, isophorone diisocyanate (IPDI) and 1,4-butanediol or trihydroxylmethylene propane as hard segments. The purpose of this paper is to explore possibility of PCUs used as secure and better biostable cardiovascular materials.The structure of polymer synthesized was analyzed by FT-IR and 1H-NMR. Molecular weights of the polymer were measured by GPC and discussed the effect of NCO/OH molar ratio. DSC was used to characterize their thermal properties and the effect of NCO/OH molar ratio and crosslinking on microphase. Mechanical properties and shape memory effect of materials was measured. The effect of NCO/OH molar ratio, hard segment content and chemical structure on mechanical properties of PCUs was also discussed. The results showed degree of microphase increased and molecular weight decreased with NCO/OH increased. PCUL1-200 had representative microphase demixing structure and good mechanical properties (ultimate tensile stress exceeded 40 MPa and elongation exceeded 300 %). And degree of microphase decreased with NCO/OH increased for crosslinked PCUs.Biodegradation behaviors of PCUs were studied in vitro by meight loss. PCUL1-200 and PCUL2-132 showed better biostability, and their weight losses were not exceeded 0.6 % after 9 weeks in vitro. PCUL2-132 showed good enzyme biostability and its weight loss was not exceeded 1 % after 9 weeks. The results indicated the materials had better biostability.