| Polymer liquid crystals(LCPs),which have extremely high strength and modulus,excellent dielectric and flame retardancy.high temperature and chemical resistance,and low expansion coefficient,shrinkage and density,are widely used.In the high-tech fields such as electronics and electrical appliances,aerospace,defense and military,optical communications,and various industrial sectors of the national economy such as automobiles,machinery,and chemicals.Polymer liquid crystals based on supramolecular interaction have attracted much attention in recent years due to their ease of design and regulation.The acrylate polymers have excellent oil resistance,weather resistance and aging resistance.Acrylate copolymers have excellent oil resistance,weathering resistance and aging resistance.Acrylate copolymers with different compositions and structures are synthesized and ionized.Polymer liquid crystals are formed based on supramolecular interaction.The relationship between composition and structure and liquid crystal behavior is studied,which can lay a foundation for the preparation of high performance acrylate copolymer liquid crystals.Several acrylate copolymers were synthesized by radical polymerization and reversible addition-fragmentation chain transfer polymerization,and their functional structural units were ionized to construct polymer liquid crystals by supramolecular action.The polymer structure was characterized by FTIR,'H NMR and GPC.The thermal properties of the polymer were investigated by DSC.The liquid crystal polymer liquid crystal texture was observed by POM.The results of FTIR and 1H NMR indicated that the absorption peaks of the functional groups corresponding to the structural units in the copolymer and the chemical shifts of the hydrogen atoms appeared in the corresponding spectra of the polymer,and the amounts of the components were substantially close to the feed ratio.The molecular weight and distribution test results of GPC showed that the molecular weight distribution of the block copolymer synthesized by RAFT was relatively narrow,and both were less than 2.0.DSC results showed that the copolymer liquid crystal formed by polymerization of DMAEMA and LMA or MMA respectively,in which the liquid crystal system of the random copolymer had a high liquid crystal cell content,section changes appeared in the high temperature,and the block copolymer liquid crystal system as well as had transition in high temperature around 175?.For the block copolymer P4VP/MO-b-PnBA,the transition occurs between 210? and 230?,and the temperature increases to some extent with the increase of 4VP content.The POM results showed that the liquid crystal texture can be observed in the corresponding temperature range of the block copolymer liquid crystal,while the liquid crystal texture can be observed only in part of the random copolymer liquid crystal,and the block copolymers were more likely to form the liquid crystal phase.For block copolymer P4VP/MO-b-PnBA,except that the polarized texture can not be observed with 10%4VP content,the other two can be observed.The reason why the polarized texture can not be observed is that the content of liquid crystal elements is poor.And the results observed by POM were consistent with DSC.The tensile test results of the block copolymer P4VP-b-PnBA showed that under the premise of the content of 4 VP was less than 30%,the elongation at break and the breaking strength of the block copolymer are both to some extent with the increase of the content of 4VP.When the content of 4VP is 10%,the elongation at break is 243%,and the strength at break is 1.43 MPa;when the content is 20%,the elongation at break is 251%,and the strength at break is 5.59 MPa;when the content is 30%,the elongation at break is 320%,and the strength at break is 10.77 MPa. |
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