The Process Exploration And Application Of Polyurethane With Alkynyl

Polyurethane has been widely used as heart valve,interventional catheter,soft tissue reconstruction and elastic medical devices due to good biocompatibility,excellent mechanical properties,low cost and easy processing.The most important is that performance is highly controllable.The traditional polyurethane can not be enough for all requirements of biomaterials to be implanted in the long term.In order to meet clinical applications,the functional modification of polyurethane is of great significance.In this study,we optimized the synthesis route of polyurethane modified by alkynyl and set up an amplification device.Results of orthogonal experimental optimization for raw materials showed that when 4 equivalents of bromopropyne,1.5 equivalments of NaH was in130mL anhydrous THF,the yield of pre-DPPD was higher and when the reaction happened with NaNO₂ dropping rate of 0.5m L/min,NaN₃ dropping rate of 2mL/min and the concentration of 0.75mol/L at 0?,the yield of 4-azidobenzoic is higher.DPPD amplification process results showed that the yield with novel device was on average more than 85%,single output was about 2 times that of the ordinary devices at least,both in terms of yield and quality was superior to ordinary one.The PTMG diol was used as the soft segment,and HDI togerther with the small molecular diol DPPD was used as the hard segment of the polyurethane.The results of FT-IR following the systhesis of prepolymer showed that the prepolymerization time of PTMG with a molecular weight of 650,and 2000 was respectively120min,180min when the mass wa same.RGD has been certified to be a potent ligand in the ECM and can be combined with intergrins to form a mechanoreceptor.In this study,we tried to get structures with different densities and transverse spacing of RGD on polyurethane by changing the ratio of hard segments and the leghth of soft segments.First,polyurethane with alkynyl side chains was systhesized using DPPD with alkynyl groups,and then 4-azidobenzoic acid was grafted on the polyurethane by click reaction.After that,RGD was modified through the reaction between the amino groups on RGD and the activated carboxyl groups on 4-azidobenzoic acid.The chemical structure of the target materials and functionalized polyurethane was chaeacterized with FT-IR,¹HNMR,Raman,XPS.The results certified that chemical structure of materials was correct.Polyurethane with alkynyl content ranging from0.073-1.14mmol/Gptmg and polyurethane with carboxyl content ranging from0.09819-0.7740mmol/g PU-D was obtained.And the efficiency of the click reaction was about 90%.The RGD content of polyurethane functionalized by peptide distributed gradiently.The micro-phase structure of polyurethane was analyzed with SAXS,AFM and DSC.The results showed the annealling temperature of alkynyl polyurethane was increased to 180?and modification of RGD could enhance the degree of micro-phase separation.Finally,cell adhesion behavior of two groups of materials with the same RGD spacing but different densities and the same RGD densities but different spacing was studied.The results showed that in a certain range the higher the RGD density was,the better the cell adhesion was.Simultaneously,RGD spacing can affect cell adhesion and morphology,too small spacing of RGD would result in poor cell adhesion.