Design, Synthesis, And Phase Behavior Of Side Chain Liquid Crystalline Polymers Without Flexible Spacer

This dissertation is focused on the investigation of the phase behavior and phasestructures of side chain liquid crystalline polymers (SLCPs) without flexible spacer.Different chemical structures polymers were synthesized in order to study thefunction of flexible spacer in side chain liquid crystalline polymers. Meantime, sidechain liquid crystalline polymers without flexible spacer is successfully synthesizedthrough ATRP living radical polymerization in order to investigate the function ofmolecular weight and side chain to this kind of side chain liquid crystalline polymers.Through the studying,we can understand some essence about the side chain liquidcrystalline polymers without flexible spacer.(1)A series of polymers with different steric hindrance, poly{2-[(4’-decyloxybiphenyl)oxycarbonyl]-styrenes},poly{3-[(4’-decyloxybiphenyl)oxycarbonyl]-styrenes}, poly{4-[(4’-decyloxy biphenyl)oxycarbonyl]-styrenes}(PVDDE-1～PVDDE-3)were designed and successfully synthesized via free radical polymerization. Theexperiment results revealed that the phase behavior of side chain liquid crystallinepolymers without flexible spacer was strongly depended on the steric hindrancebetween main chain and side chain. Steric hindrance of PVDDE-1～PVDDE-3decreases, thermal stability and phase stability of the polymers gradually increases.This results show that steric hindrance hinder the formation of ordered structure.(2) A series of side chain liquid crystalline polymers with different molecularweights (Mn) and low molecular weight distributions have been successfullysynthesized via atom transfer radical polymerization. The experiment results revealedthat phase behaviors of polymers were strongly influenced by molecular weights,glass transition temperature and phase transition temperature and decompositiontemperature of polymers gradually increased with the increase of molecular weights.molecular weights beneficial to stabilize the liquid crystalline phase.(3) A series of side chain liquid crystalline polymers with different side chain havebeen successfully synthesized through free radical polymerization. The experimentalresults show that only PVDDE-3form ordered liquid crystalline structure. It isrevealed that the foemation of liquid crystalline structure were strongly influenced byside chain structure.