Homopolymerization Of Acrylate And Copolymerization With Acrylonitrile Initiated By Lewis Base In Dmso Solvent

The research on the polymerization of polar vinyl monomers has attracted much attention thanks to the special functionality of the polymers prepared by such monomers.In addition,the living controlled polymerization of polar vinyl monomers has always been an important goal pursued by academia.In this paper,using DMSO as solvent and metal-free Lewis base as initiator under mild conditions,the homopolymerization of acrylate and the copolymerization of methyl acrylate and acrylonitrile were studied.The main research contents and conclusions are as follows:1.Research on homopolymerization of acrylate.In various solvents(THF,DMF,DMSO,etc.),using DBU as initiatior,the polymerization of MA is conducted at room temperature.It was found that only in DMSO solvent,the medium active monomer MA can be polymerized by LB nucleophilic attack.Detailed research on the polymerization conditions shows that lower temperature and monomer concentration help to inhibit the occurrence of polymerization side reactions.When the reaction temperature is 15? and the monomer concentration is 25 wt.%,The monomer conversion rate reaches 25%.Mn=5000 g/mol,PDI=1.17.Mechanism studies conducted by means of NMR,FT-IR,MALDI-TOF,etc.The results show that the MA monomer can be activated in DMSO solvent and attccked by DBU thtough Michael addition.The active chain is mainly terminated by carbon anions back biting the carbonyl group.Based on the above research,the polymerization behavior of other monomers initiated by LB/DMSO was preliminarily discussed.The results showed that the steric hindrance and electronic effect of the substituent had a significant effect on the conversion rate of the monomer,EA>MA>BA,MMA cannot polymerize,4-vinylpyridine(4-VP)containing strong electron-withdrawing groups and vinylidene chloride do not polymerize2.Study on copolymerization of methyl acrylate and acrylonitrile.It was found that DBU can initiate the copolymerization of AN and MA:copolymerization in DMSO solvent.Further study on copolymerization kinetics,the results show that the two monomers AN and MA can initiate each other.Futhermore,we carefully examined the effects of the conditions on the copolymerization.The results show that lower reaction temperature and monomer concentration contribute to the increase in polymer linearity and yield,when the reaction temperature is 15? monomer concentration reached at 22 wt.%,the polymerization yield reached 63%,Mw=70×104 g/mol,PDI=1.84,[MA]/[AN]=1.5/98.5.The copolymer can be electrospun and has good spinnability.DSC/TGA research shows that compared with commercial polyacrylonitrile,the AN-MA copolymer has a low preoxidation cyclization temperature,a wide temperature range,and a high-temperature carbon retention rate of 56-61%,which has potential advantages in the preparation of high-performance carbon fibers.3.Anionic polymerization of 1,2-diphenyl-1,3-butadiene(1,2-DPB).We using strong nucleophilic alkyllithium as iniatior,carefully examined the effects of the conditions on the anionic polymerization of 1,2-DPB.The results show that THF-CHX mixed solvent can effectively suppress the occurrence of side reactions and improve the polymerization efficiency,the conversion rate reached 99%,Mn=21000 g/mol,PDI=1.05.It is found that the microstructure of P(1,2-DPB)is mainly affected by temperature,and the content of 1,4-structure increases with decreasing temperature.