Study On Synthesis And Properties Of Oxyheterocyclic Butane Based Silicone Containing Monomers For Cationic Photopolymerzation

Cationic photopolymerization has advantages of oxygen-insensitivity,low volume shrinkage,strong adhesion and post-curing,therefore,it plays an irreplaceable role in the field of photopolymerization.However,at present,there are few monomers used for cationic photopolymerization,and the polymerization rate of the monomers used for cationic photopolymerization is slower than that of the monomers used for free radical photopolymerization,which limits the application of cationic photopolymerization in industry.Hence,the development of monomers with high reactivity and excellent physical and mechanical properties used for cationic photopolymerization is of great significance to promote the development of cationic photopolymerization.Polysiloxane has excellent heat resistance,hydrophobicity,electrical insulation and physiological inertia,while oxyheterocyclic butane monomers have low viscosity,good adhesion,low volume shrinkage,high polymerization activity and low toxicity,therefore,the monomers,which combine the structures of both plolysiloxane and oxyheterocyclic butane,will have advantages of both compounds and a broader application prospect.The development of the monomers has important theoretical significance and application value.Based on this,a series of oxyheterocyclic butane-based silicon-containing monomers was synthesized in this study.The influences of monomer structures on their photopolymerization activity,and the physical and mechanical properties,and surface properties of polymers with them were explored in detail to obtain the internal connection between their structures and properties and provide theoretical basis and experimental data for their practical application.The main research contents and conclusions are as follows:1.In this paper,an oxyheterocyclic butylsilane coupling agent(ETPO),three mono-oxyheterocyclic butane-based organosiloxane monomers with different molecular weights(MOSi-n,n=3,6,9),3-ethyl-3-((2-(vinyloxy)ethoxy)methyl)oxo-heterocyclic butane(EVEO)and a bi-oxyheterocyclic butane-based organosiloxane monomer(BOSi)were synthesized.2.The photopolymerization kinetics of ETPO,MOSi-n,EVEO and BOSi were studied.It was found that the increase of initiator concentration and light intensity can enhance the conversion and polymerization rate of monomers.ETPO is better than KH560 in enhancing the conversion of E4221.For EVEO,the polymerization of double bonds can promote the conversion and the polymerization rate of epoxy groups.Among the MOSi-n,MOSi-9 has the best photopolymerization performance.The epoxy conversion of BOSi is higher than that of MOSi-6,but slightly lower than that of MOSi-9.3.ETPO can improve the tensile property,adhesion and water contact angle of cured films of E4221 and TPGDA/E4221.The tensile strength of the cured film of E4221 reached 15.9 MPa,the elongation at break was 21.4%,the adhesion for PVC was 5B,and the water contact angle was 85.3°.The tensile strength of hybrid cured film of TPGDA/E4221 reached 11.9 MPa,elongation at break was 15.7%,the adhesion for iron sheet was 5B,and the water contact angle reached 88.2°.4.MOSi-n can enhance the heat resistance,tensile property,adhesion and hydrophobicity of the cured film of E4221.The cured film of E4221 containing MOSi-9 exhibited the best comprehensive performance.Its water contact angle reached 91.7°,and tensile strength and elongation at break were 14.3 MPa and 30.6%,respectively.Its adhesion for PVC reached 5B.5.BOSi can boost the tensile property,heat resistance,adhesion and water contact angle of cured films of E4221 and TPGDA/E4221.When BOSi content was 15 wt%,cured films had excellent properties.T5%,Tmax1 and Tmax2 of the cured film of E4221 were 326?,416? and 590?,respectively.Its tensile strength and elongation at break reached 23.5 MPa and 15.4%,respectively.Its adhesion for PVC was 5B,and its water contact angle on the surface was 87.4°.The tensile strength and elongation at break of the cured film of TPGDA/E4221 reached 18.6 MPa and 17.4%,respectively.Its adhesion for iron sheet was 5B,and its water contact angle was 90.6°.