Synthesis And Properties Of Temperature Sensitive Functional Polymer Materials Containing Liquid Crystal Phase

Poly N-isopropyl acrylamide(PNIPAM),as a kind of temperature-sensitive polymer with low critical solution temperature(LCST),has a phase transition temperature of around 32 ℃,and can be brought close to the human body through appropriate modification.The temperature has thus been extensively studied by people.At the same time,by introducing some functional groups into the PNIPAM,it is possible to give it a variety of intelligent characteristics of stimuli response.Based on the temperature-sensitive properties of NIPAM,this topic prepares a functional polymer material with double response of light and temperature by copolymerizing it with a monomer of a conventional azobenzene chromophore.On the basis of this,the use of cardanol instead of phenol for the reaction,the problem of miscibility and poor thermal stability of conventional azo is improved,and the monomer containing the cardanol azo chromophore is prepared and combined with NIPAM.After polymerization,the performance changes of both the light and temperature were studied.Finally,the research of the subject was further extended,and the copolymer of cholesteric liquid crystal and NIPAM was attempted to explore the influence of the introduction of cholesteric liquid crystal on the optical properties and other properties of the polymer.The specific work is as follows:(1)A phenol azobenzene compound is prepared,and a monomer is obtained by introducing a flexible spacer group and a double bond,and copolymerized with NIPAM to prepare a temperature sensitive material containing an azo liquid crystal phase.The products and intermediates were characterized by Fourier transform infrared spectroscopy(FTIR)and nuclear magnetic resonance spectroscopy.Ultraviolet spectroscopy(UV-Vis)and polarized light microscopy(POM)were used to study the optical properties of the polymer.The UV-visible spectrophotometer was used to investigate the factors affecting the temperature sensitivity of the polymer.(2)Using cardanol instead of phenol,preparing a cardanol azo monomer,and copolymerizing it with NIPAM to prepare a temperature sensitive material containing a cardanol azo liquid crystal phase.The structures of the products and intermediates were characterized by Fourier transform infrared spectroscopy(FTIR)and nuclear magnetic resonance spectroscopy.Ultraviolet spectroscopy(UV-Vis)was used to study the optical properties of the polymer.The relative molecular mass and relative molecular mass distribution of the product obtained by copolymerization were confirmed by gel chromatography(GPC).The spectrophotometer test acquires the LCST of the copolymer and studies the factors affecting its LCST.(3)The cholesteric derivative monomers were separately prepared by two methods,and the prepared monomers were solution-polymerized with NIPAM.The structures of the products and intermediates were characterized by Fourier transform infrared spectroscopy(FTIR)and nuclear magnetic resonance spectroscopy.The optical properties of the Liquid crystal monomer were investigated using a polarizing microscope(POM)and the temperature sensitivity of the polymer was investigated by means of an ultraviolet-visible spectrophotometer.