Preparation Of Imidazolyl Ionic Liquid Copolymers/Composites And Their Electrorheological Properties

Ionic liquids?ILs?with unsaturated chemical bonds can undergo homopolymerization,or copolymerize with other monomers with double bonds to form macromolecules.The special properties of ionic liquids would be introduced into the polymer framework,which has great prospects in electrorheological fluid?ER?applications.However,the density of polymers formed by the homopolymerization of ionic liquids was large,and thus the prepared ER fluids had poor sedimentation properties.In addition,the formed homopolymer is unstable and easily deformed.Therefore,1-butyl-3-vinylimidazolium tetrafluoroborate ionic liquids containing unsaturated bonds were selected as the main research object and copolymerized with different monomers,after which,the electrorheological properties of the copolymers were studied.The main contents are as follows:Firstly,using 1-butyl-3-vinylimidazolium tetrafluoroborate ionic liquid?[C₄VIm][BF₄]?and styrene as comonomers,a series of cross-linked polyionic liquids P?C₄VIm/E/S?[BF₄]with different amounts of cross-linking agent?ethylene glycol dimethacrylate,EGDMA?were prepared and characterized by elemental analyses,such as FT-IR,TG,XRD and SEM.Finally,the copolymer was tested for electrorheological properties and settling performance.The results showed that when the EGDMA content was 10%?mass fraction?,the ER performance was the best,so was the settling performance.Next,we select 1-vinylimidazolium tetrafluoroborate ionic liquid?[C₄VIm][BF₄]?and double salt ionic liquid?1,6-hexanediyl-3,3'-1-vinylimidazolium tetrafluoroborate,[C₆?VIm?₂][BF₄]₂?for copolymerization.The molar ratio of the two monomers were controlled during the experiment.Four groups of Cross-Linked polyionic liquids P[H/C₄VIm][BF₄]were prepared by conventional free radical polymerization?molar ratio of double salt to mono-salt was 1:1,1:5,1:10,1:20,respectively?.A series of intermediate products and target products were characterized by IR,TG,XRD,SEM,etc.,and their electrorheological properties were tested.The results showed that when the double salt content is the least?the group of 1:20?,the prepared particles had the largest size and the best electrorheological properties.Finally,1-methyl-3?triethoxysilylpropane?imidazolium chloride?TMIC1?ionic liquid and poly-1-vinylimidazolium tetrafluoroborate polyionic liquid?P[C₄VIm][BF₄]?were used as shells respectively,using TiO₂ as the core,two composite materials IL-TiO₂ and PIL-TiO₂ were prepared.Compared with pure TiO₂,the dispersibility of the two composites became better,but the ER performance was degraded.The reasons why the ER performance of the two composites decreased need be further studied.