Synthesis And Modification Of 1,3-Pentadiene-based C₅ Resin

C6 petroleum resin is a kind of thermoplastic resins prepared using C5 fraction as raw material. It can improve viscosity and be dissolved in benzene, toluene, and so on. It is miscible with some resins, such as ethylene-vinyl acetate copolymer and polyethylene. There are widespread applications in many fields, such as tackifier for hot melt adhesive, traffic paints and rubber component. C5 petroleum resin was prepared using aluminium trichloride or alkyl aluminium chlorides as the catalyst and toluene as the solvent. The effects of solvent and catalyst on molecular weight, microstructure and property of polymer were obviously. Aluminium trichloride or alkyl aluminium chloride's separation from the reaction system was difficult. A lot of waste water was produced.In the present thesis, cationic polymerizations of 1,3-pentadiene,1,3-pentadiene and isoprene, and 1,3-pentadiene and styrene have been carried out by using SbCl3/AlCl3 or Et3NHCl-AlCl3 as catalysts. Microstructure and properties of polymers were characterized and analyzed by FT-IR, 1H NMR,13C NMR, GPC, TGA and DSC. The detailed results and conclusions are as follows:Firstly, poly(1,3-pentadiene) was synthesized using concentrated 1,3-pentadiene as raw material, SbCl3/AlCl3 as catalysts, and n-heptane, toluene or CH2Cl2 as solvent. Microstructure of polymer was characterized by FT-IR,1H NMR and 13C NMR. The effects of concentration of SbCl3, concentration of AlCl3, kinds and concentration of solvent, and reaction temperature on properties of polymer were investigated. The reason that the solvent significantly affected molecular weight and microstructure of poly(1,3-pentadiene) was discussed. Thermal properties were analyzed by DSC and TGA. The softening point of poly (1,3-pentadiene) was 139? which is the highest softening point of 1,3-pentadiene-based resin reported. Finally, it was compared with commercially available resins.Secondly, poly(1,3-pentadiene) was synthesized using Et3NHCl-AlCl3 as catalyst and toluene or CHCl3 as solvent. The effects of composition of ionic liquid, amount and kinds of solvent, polymerization temperature and polymerization time on microstructure and properties of the resin were investigated. Thermal properties and color stability were analyzed. The effects of amount of ionic liquid and yield on cyclization degree were investigated. Initiation mechanism and cyclization mechanism were studied. Ionic liquid were easily separated from the system in the post-processing. Ionic liquid could substitute for the traditional catalyst AlCl3 and solve these problems of traditional catalyst encountered, such as emulsion and waste production. It was a green technology for producing petroleum resin.Thirdly, the high softening point and light copolymers were synthesized using isoprene and styrene as comonomers, Et3NHCl-AlCl3 as catalyst, and chloroform as solvent under the above green technology. The effects of polymerization conditions on microstructure and properties were investigated. The relationship between microstructure and properties of copolymer were studied by 1H NMR, TGA and DSC. It is concluded that cyclization reaction is more likely to occur when two monomers are added simultaneously in the copolymerization of isoprene with 1,3-pentadiene. Because the cationization of pendent double bonds (initiation step of cyclization) in 3,4-units of isoprene is favoured by both the smaller steric hindrance for proton attack on 1,1-di-substituted double bonds and the high stability of the formed tertiary carbocation, the cyclization degree of copolymer are more higher. The stabler benzene ring is introduced into the polymer chain in the copolymerization of styrene with 1,3-pentadiene, the color of polymer becomes lighter. The glass transition temperatures of two kinds of copolymers have only one, which shows that they are random copolymers.Finally, the grafted resin was synthesized using glycidyl methacrylate as grafting monomer, and styrene as comonomer. Structure of the grafted resin was characterized by FT-IR. The absorption peak of benzene ring was found, which showed that styrene did participate in the grafting process of glycidyl methacrylate onto poly(1,3-pentadiene). The main influence factors of grafting conditions were studied by Plackett-Burman design method. The grafting mechanism was discussed. Experimental results show that styrene can promote glycidyl methacrylate to graft 1,3-pentadiene-based resin.