Preparation Of Polysiloxane-polyurethane Film And Its Copolymerization With Hydrophilic Monomers

Silicone polymers have extensively been used due to their excellent properties such as heat and cold resistance,weatherability,good biocompatibility,ozone resistance,and UV damage capability.Polyurethane materials have also extensively been used owing to their excellent properties such as excellent abrasion resistance,oil resistance,chemical resistance and tensile strength,high elongation,and good shock absorption effect.Therefore,preparing polysiloxane-polyurethane copolymers to obtain a material that combines the excellent properties of both is a very important research topic.Firstly,the PDMS-IPDI intermediate macromonomer was obtained through the reaction of carbinol(hydroxyl)terminated polydimethylsiloxane and isophorone diisocyanate.It was then capped with 2-hydroxyethyl methacrylate(HEMA)to obtain the PDMS-PU macromonomer.The polysiloxane-polyurethane(PDMS-PU)film was prepared by radical polymerization,the reactions are performed without solvents and additives,The preparation process was verified by infrared spectroscopy.Through testing the mechanical properties of the film,it is found that its tensile properties and elastic modulus properties are good,and the film has good optical transparency,indicating that the prepared PDMS-PU film does not produce phase separation.Then,PDMS-PU-co-DMA-co-NVP films were prepared by radical copolymerization of the prepared PDMS-PU macromonomer with hydrophilic monomers and their properties were investigated.It was found that due to the formation of a crosslinked network,the addition of hydrophilic monomers in the polysiloxane-polyurethane leads to an increase in mechanical properties.However,as the content of the hydrophilic monomer increases,the compatibility of the two decreases and the optical transparency of the copolymer film decreases.However,copolymerization with hydrophilic monomers did not improve the hydrophilicity of the polysiloxane system.The results from the surface element analysis showed that although the N element in the hydrophilic monomer appeared on the surface of the copolymer film,the content of Si on the surface did not significantly reduced,and in addition the siloxane is readily accumulate to the surface,all of which make the prepared copolymer membrane still hydrophobic.The incompatibility of the silicone with the hydrophilic monomer causes the wavy structure to appear on the surface of the copolymer film.Finally,this study explored a one-step reversal method to improve the surface hydrophilicity of PDMS film.Hydrophilizing agent(TMSEMA)was added to the PDMS preparation system,The trimethylsiloxy structure in TMSEMA is then hydrolyzed by a one-step soaking treatment with a potassium hydroxide solution to form hydrophilicity hydroxyl group,which imparts hydrophilicity to the PDMS film in a reverse manner.Through testing,it has been found that the hydrophilicity of PDMS has been greatly improved.The ATR-FTIR test also showed the production of hydrophilic group hydroxyl and carboxylate salts.In addition,the saturated water content,surface morphology and protein adsorption performance of PDMS film before and after modification were also tested.