| Because the backbone of low molecular weight polyisobutylene(LMPIB) consists of saturated carbons, LMPIB possesses excellent ozone resistance, ultraviolet resistance, chemical resistance, and moisture barrier. Also, it exhitbis high volume resistivity and electrical insulation, it is compatibile with high non-polar polymeric materials, and can disperse well in non-polar materials at low temperature. These features makes LMPIB very useful for fuel additives, rubber processing aid, food packaging, electrical cable and so many aspects. However, a LMPIB chain has only one end with unsaturated C=C double bond and the reactivity of the double bonds is relative low. It may extend the applications of LMPIB to increase the end double bond and functionalization of the end double bond.In this work, firstly, LMPIB was pyrolyzed to increase the functionality of end double bonds and synthesize telechelic polyisobutylene; then, LMPIB and telechelic polyisobutylene were epoxidized with two organic epoxidizing agents; finally, the synthesized epoxides were blended with cycloalicyclic epoxy resins.Telechelic polyisobutylene could be obtained after pyrolysis of LMPIB. A method to determine the functionality of double bonds was established based on viscosity and Iodometry method. The structure of end double bonds of the products were analyzed with FT-IR and 13C-NMR and the effects of pyrolysis conditions on the functionality of double bond were investigated. The parameters of pyrolysis were optimumized. After pyrolysis at 315℃for 1hr, the functionality of double bonds could be 1.63.Dimethyl dioxirane(DMDO) and tert-butyl hydroperoxide(TBHP)/Mo O3 were adopted as epoxidizting agents. The effects of added solvents, raw material ratio, reaction temperature, reaction time on the conversion of double bonds and yield as well as the epoxy value of the products were investigated. It was found that TBHP/Mo O3 system is better than DMDO for epoxidizing LMPIB. With DMDO, the conversion of double bonds could be 69.10% and the yield could be 66.95% for LMPIB; the epoxy value of the product could be 0.1388 mol/100 g. For TLMPIB, the conversion and yield could be 31.87% and 79.7%, respectively and the epoxy value is 0.0513mol/100 g. With TBHP/Mo O3,the conversion of double bonds could be 76.02% and the yield could be 72.49% for LMPIB; the epoxy value of EPIB is 0.1682 mol /100 g. For TLMPIB the conversion and yield could be 33.59% and 98.02%, respectively, the epoxy value of ETPIB is 0.0665 mol/100 g.DSC analysis indicated that the reactivity of epoxidized LMPIB are similar to that of cycloalicyclic epoxy resins. They reduced the activation temperature of TTA22 with anhydride and increased the activation temperature of CY179 slightly. In epoxy resin blending system, with the increasing EPIB and ETPIB quantity, light transmittance of products decrease about 5%. EPIB and ETPIB have better compatibility with TTA22, TTA26 and CY179 according to the calculated solubility parameter based on three-dimensional solubility parameter resins inferred consistent resin compatibility. Thermogravimetric analysis(TGA) showed that EPIB and ETPIB improved thermal stability of TTA22 and CY179 cured resin system product, the thermal decomposition temperature is increased. After thermal aging and UV aging experiments each 7 days, CY179 and TTA22 blends cured product transmittance and yellowing factor show, EPIB and ETPIB oxygen is added to improve the heat resistance and UV aging properties of epoxy curing system. |
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