Study On Preparation And Modification Of Low-toxicity Non-isocyanate Polyurethane Photosensitive Resin

With the continuous development of modern medical technology,customized medical devices combined with 3D printing technology have been widely used clinically.Photosensitive resin is one of the materials commonly used in the manufacture of customized medical devices,but traditional photosensitive resins have problems such as easy volatilization of monomers and high biological toxicity in the preparation of raw materials,which seriously hinder the application of photosensitive resins in medical treatment.At present,medical-grade photosensitive resins that can be used for 3D printing are seldom studied and are monopolized by a few foreign companies.Polyurethane materials have excellent biocompatibility and mechanical properties,and are considered to be one of the most ideal biomedical materials at present.However,the preparation of commonly used polyurethane materials mostly uses isocyanate monomers,which are more toxic.Non-isocyanate polyurethane is comparable to traditional polyurethane due to its simple synthesis route,environmentally friendly source of monomer raw materials,biocompatibility and mechanical properties,and has become a research hotspot in recent years.In this study,the Diels-Alder reaction of alicyclic diamine and propylene carbonate was used to synthesize a low molecular weight non-isocyanate polyurethane(NIPU)low molecular weight monomer without using any catalyst and solvent.Isocyanate polyurethane prepolymer(NIPU)reacts with methacrylic chloride to synthesize a non-isocyanate polyurethane methacrylate(NIPUMA)monomer.Adopt polyethylene glycol diacrylate(PEGDA)as modified material,triethylene glycol dimethacrylate(TEGDMA)as crosslinking agent and diluent,camphor ketone(CQ)and 2-(dimethylamino)Ethyl methacrylate(DMAEMA)was used as a photoinitiator to prepare a non-isocyanate polyurethane(NIPU)photosensitive resin,and its cytotoxicity and blood compatibility were evaluated.The research results show that when the content of PEGDA is 6 wt.%～27 wt.%,the photo-sensitive resin has no potential cytotoxicity and is a low-toxic NIPU photosensitive resin,and when its content is 13 wt.%,the tensile and flexural strengths have the best values,respectively.It is 63.05 MPa and 118 MPa.On this basis,further explore the performance changes of low-toxic NIPU photosensitive resin with 0 wt.%～24 wt.% PEGDA content.The results show that the heat distortion temperature of NIPU photosensitive resin is between 66.9℃ ～ 79.5℃,and with the increase of PEGDA content,the tensile strength and flexural strength of the resin first increase and then decrease.When the PEGDA content reaches 12 wt.%,there is a maximum value are 63.92 MPa and 90.78 MPa,respectively.With the increase of PEGDA content,the tensile strength and flexural strength of the resin first increase and then decrease.When the PEGDA content reaches 12 wt.%,there is an optimal value,which is 63.92 MPa and 90.78 MPa,respectively.In addition,according to the results of TGA analysis,heat deflection temperature analysis and DMA analysis,when the content of PEGDA is between 12 wt.% and 20 wt.%,NIPU photosensitive resin exhibits higher thermal stability,and the initial thermal decomposition temperature is about 254℃,the highest heat distortion temperature can reach 79.5℃,and the highest glass transition temperature can reach 120.43℃;the evaluation results of cytotoxicity and hemolysis rate show that when the content of PEGDA is less than 24 wt.%,the cells co-cultured with NIPU photosensitive resin extract can survive exceeds 80%,and the hemolysis rate is less than 0.2%,indicating that the resin has no potential cytotoxicity and hemolysis.The photosensitive resin prepared in this study has the characteristics of higher tensile and flexural strength,better thermal stability,and low toxicity.It has certain significance for further promoting the clinical application of customized medical devices and improving the quality of life of patients.