Synthesis Of Polyurethanes Based On A Novel Tri-peptide Derivative

This study is to combine biocompatibility and biodegradation of tri-peptide withlow cost and designable structures to synthesis polyurethane materials modified withhigh bioactive tri-peptide. A new tri-peptide derivative (PLP) is synthesized fromlysine and phenylalanine unit by carbodiimide reaction. The structure of PLP isvariable by replacing phenylalanine with otherα-amino acid and the synthesis routineis relatively simple with high productivity. PLP-extended polyurethanes (PU-PLP) aresynthesized with PEG and PCL as soft segment, HMDI and HDI as hard segment,Lys-OEt and BDO as chain extender, and the structure and properties of PU-PLP arestudied.Structures of PLP and PU-PLP are well proved by 1H-NMR and FTIR spectra.The results of FTIR, DSC and TGA suggest that hydrogen bond, phase separatedegree and glass-transition temperature of PU-PLP decreases while thermal stabilityincreases with increasing the molecular weight of soft segment. Main chains ofPEG-segmented and HDI-segmented PUs are more flexible than PCL-segmented andHMDI-segmented PUs respectively with low glass-transition temperature. Due toester and methene bond, PCL-segmented and HMDI-segmented PUs'thermalstabilities are lower. PLP modification makes PU hydrogen bond stronger, higherglass-transition temperature and lower thermal stability than Lys- or BDO-extended.Water uptake of PEG-segmented PU is bigger than PCL-segmented. Bulk waterabsorption of PU-PLP is lower than unordered ranging Lys-extended PUs while thesurface water contact angle is smaller than Lys-segmented PU.Bonding strength of PU-PLP decreases with increasing molecular weight of softsegment, and PCL-segmented PU-PLP decreases slow as the strong polarity to basematerials. PLP modification makes PU-PLP higher hard segment content and bonding strength than Lys- and BDO-extended PUs, indicating that copolymerization of PLPinto polyurethanes improve the adhesive property. Cell viability of PU-PLP is 10%higher than BDO-extended polyurethane, indicating that PLP modification improvethe biocompatibility of polyurethanes.According to the results, modification of the new peptide derivative PLP intopolyurethanes not only improves the biocompatibility but also get a high adhesiveproperty. For practical applications, adjusting different proportion of PEG/PCL,molecular weight of soft segment and HMDI/HDI can meet different demands withstrong operability, which indicates that polyurethanes extended by the noveltri-peptide derivatives chain extender can be used in potential application ofbiological adhesive.