Preparation And Properties Of PH Sensitive And Organosilicon Modified Poly(ester-urethane)s

In recent years,"smart"has become one of the most popular terms in the 21^st century,such as the application of smart phones,smart bracelets and smart homes.The progress of these technology products is inseparable from the development of polymer industry and polyurethane industry.Therefore,polyurethane products are becoming more and more intelligent,and modified polyurethane has become one of the hot spots of scientists.The paper is divided into three parts??.Preparation and properties of pH sensitive poly?ester-urethane?s with pyridine group in side chain?PEU-py?:Dihydroxy-terminated pyridine compounds?PyDH?was prepared by Michael addition from 1-thioglycerin?TG?and 4-vinylpyridine?VP?,and the prepolymer polyoxycyclohexanone-poly?ethylene glycol?-polyoxycyclohexanone?PEDO?was prepared by ring-opening polymerization with PDO as monomer and PEG as initiator;Then,the mixture of PyDH and PEDO was extended by 4,4`-diphenylmethane diisocyanate?MDI?,and a series of products?PEU-Py-?^??with different content of pyridine group were prepared.The chemical structures of the products were characterized by ¹H NMR,FT-IR and gel permeation chromatography?GPC?.The influence of the content of pyridine group in the side chain on the thermal properties,crystallization properties,surface hydrophilicity,mechanical properties and in vitro degradation properties of the polymers were studied.The pH sensitivity of the polymers and application in drug release were studied in detail.The results of Differential scanning calorimetry?DSC?and X-ray powder diffraction?XRD?showed that the degree of microphase separation and crystallization of PEU-Py films were low.Thermal gravimetric analyzer?TGA?,water contact angle,mechanical properties and in vitro degradation tests showed that with the increase of PyDH content,the thermal stability,hydrophilicity,tensile resistance and degradation rate of PEU-Py films were improved to some extent.The swelling ratios of PEU-Py films were:acid>neutral>alkaline at pH=1.5,7.0 and 12.0.The swelling ratios of PEU-Py films increased with the increase of PyDH content in acidic and neutral conditions,and decreased with the increase of PyDH content in alkaline conditions.When PEU-Py-?reached the swelling equilibrium at the 6^th hour,the swelling ratios at pH=1.5,7.0 and 12.0 were 185%,90%and 13.5%,respectively.The drug release rate of PEU-Py films were:acid>neutral>alkaline.At the 15^th hour,The drug release of PEU-Py-?at pH=1.5,7.0 and 12.0 were 86.4%,50.0%and 8.3%,respectively,thus the drug release performance could be controlled by the pH value of the environment.?.Preparation and properties of pH sensitive poly?ester-urethane?s with tertiary amino group in the main chain?PMCU?:PCL was prepared with 1,4-butanediol?BDO?as initiator and?-caprolactone??-CL?as monnor.The mixture of methyldiethanolamine?MDEA?and PCL was chain-extended by 4,4'-dicyclohexylmethane diisocyanate?HMDI?.A series of products?PMCU-1⁵?with different content of tertiary amino group were prepared.The chemical structures of the products were characterized by ¹H NMR,FT-IR and GPC.The influence of the content of side chain pyridine group on the thermal properties,crystallization properties,surface hydrophilicity,mechanical properties and in vitro degradation properties of the polymers were studied.The results of DSC,XRD,TGA,water contact angle,mechanical properties and in vitro degradation tests showed that with the increase of MDEA content,the thermal stability,hydrophilicity,tensile resistance and degradation resistance of PMCU films were improved to some extent.In addition,the pH sensitivity of the polymers and application in drug release were studied in detail.The swelling ratios of PMCU films were:acid>neutral>alkaline?pH=1.5,7.0 and 12.0?.The swelling ratios of PMCU films increased with the increase of MDEA content in acidic,neutral and alkaline conditions.When the PMCU-5 film reached the swelling equilibrium at the 9^th hour,the swelling ratios at pH=1.5,7.0 and 12.0 were 22.6%,16.6%and 6.4%,respectively.And the drug release rate increased with the prolongation of time at pH=1.5,7.0 and 12.0,while the drug release rate was:acid>neutral>alkaline.The drug release of PMCU-5 at pH=1.5,7.0 and 12.0were 52.5%,35.5%and 15.0%,respectively.The results indicated that the drug release performance could be controlled by the pH value of the environment.?.Preparation and properties of silicone modified poly?ester-urethane?s?PU-Si?:PCL,which was prepared from BDO and?-CL,was chain-extended with an excess of aliphatic diisocyanate?HBH?,and then terminated with?-aminopropyltriethoxysilane?KH550?to give a series of products?PU-Si-?^??with different content of KH550.The chemical structures of the products were characterized by FT-IR.The influence of KH550 content on the thermal properties,water absorption,mechanical properties,crystallinity,surface hydrophilicity,in vitro degradation and biocompatibility of the polymer were studied.X-ray photoelectron spectroscopy?XPS?results showed that KH550 was successfully incorporated into PU-Si films.With the increase of KH550 content,DSC and XRD showed the hard segments of polyurethane films gathered more closely and arranged more regularly.TGA,hydrophobicity,mechanical properties and in vitro degradation tests showed that the thermal stability,hydrophobicity,tensile resistance and degradation resistance of PU-Si films were greatly improved.The study of protein adsorption and platelet adhesion showed that PU-Si films possessed outstanding low protein-adsorption quantity?1.94-15.28?g/cm²?and good anti-platelet adhesion capacity,Therefore,the modified material possessed good biocompatibility and could be used in biomedical fields.