Design And Property Research Of Hydrogels Based On Amphiphilic Silicone

Silicone hydrogels are polymer networks formed by introducing organosilicon segments into the hydrogel matrix,which are generally prepared by copolymerization of organosilicon monomers and hydrophilic monomers.Silicone hydrogels combine the advantages of high oxygen permeability of silicone rubber materials and strong hydrophilicity of hydrogel materials,and have good oxygen permeability,hydrophilicity and biocompatibility,so they are widely used in the field of biomedicine.Polydimethylsiloxane(PDMS)has an oxygen permeability value of up to 600 Barrer,excellent biocompatibility,and good mechanical properties.The copolymerization of silicone macromonomers containing PDMS segments and hydrophilic monomers is a common method for preparing high oxygen permeable silicone hydrogels.However,PDMS is highly hydrophobic,so it has poor compatibility with hydrophilic monomers.The amount of PDMS added is limited,which limits the increase in oxygen permeability of the material.Introducing hydrophilic groups into PDMS segments to obtain amphiphilicity PDMS macromonomers is an effective method to improve the compatibility of silicone macromonomers with hydrophilic monomers.In this thesis,several amphiphilic silicone monomers with different structures were designed and synthesized.Then,silicone hydrogels with different structures and properties were prepared by copolymerizing silicone monomers and hydrophilic monomers.The influences of silicone monomer structure and composition on the application performance of silicone hydrogels were discussed,and the oxygen permeability mechanism was analyzed.The main research contents and conclusions are as follows:(1)Using single-ended hydroxy polyether silicone oil(PDMS-PEG-OH)and isocyanoethyl methacrylate(IEM)as raw materials,dibutyltin dilaurate as a catalyst,single methacrylate terminated silicone monomer(S-PDMS)was designed and synthesized.Using double-end hydroxy polyether silicone oil(HO-PEG-PDMS-PEG-OH),isophorone diisocyanate(IPDI)and hydroxyethyl methacrylate(HEMA)as raw materials,double hydroxyethyl methacrylate terminated silicone monomer(D-PDMS)was synthesized through a two-step reaction.The reaction process was tracked by Fourier Infrared Spectroscopy(FTIR),and the optimal reaction time was determined.The structures of the products were characterized by NMR spectroscopy(~1H-NMR).(2)Using single-ended hydroxy silicone oil(PDMS-OH)and double-ended hydroxy silicone oil(HO-PDMS-OH)as raw materials,single monomethacrylate terminated silicone macromonomers(PDMS-1)and Double methacrylate terminated silicone macromonomer(PDMS-2)were prepared.A series of silicone hydrogels with different crosslinking densities and free siloxane chain lengths were prepared by copolymerizing hydrophilic monomers and organosilicon macromonomers with different numbers of reactive terminated groups.The effects of crosslinking density and free siloxane chain length on the oxygen permeability,equilibrium water content(EWC),light transmittance and mechanical properties of silicone hydrogels were studied.The results showed that the silicone hydrogel S1 prepared from PDMS-1 had the highest oxygen permeability,EWC and elongation at break,which were 153 Barrer,40%and 178%,respectively.With the increase of the number of reactive terminated groups of the silicone macromonomers,the crosslinking densities of the silicone hydrogels increased and the free siloxane chain length became shorter,so that its oxygen permeability,EWC and elongation at break were reduced.And its light transmittance and elastic modulus have been improved.The results showed that the oxygen permeability of the hydrogel could be adjusted by changing the number of polymerizable groups of the silicone macromonomer.(3)Using the D-PDMS and sodium dodecyl sulfate(SDS)as raw materials,SDS-Si nanomicelle particles with a diameter of 132 nm were prepared by a self-assembly method.Using the nanomicelle particles SDS-Si as a crosslinking agent,a series of highly hydrophilic silicone hydrogels with different silicon content were prepared by copolymerizing the hydrophilic monomers HEMA and N-vinylpyrrolidone(NVP).The effects of silicon content and hydrophilic monomer composition on the EWC,contact angle and oxygen permeability of silicone hydrogels were studied.The Study showed that the addition of a small amount of silicon monomer can greatly improve the oxygen permeability of the hydrogel material,and at the same time,the hydrogel can maintain better hydrophilicity.