Dissertation > Industrial Technology > Chemical Industry > Synthetic resins and plastics industry > Polycondensation resin and plastic > Epoxy resins and plastics

Synthysis and Cure Kinetics of Imine and 1, 4-Dihydroxy-benzene Liquid Crystalline Epoxy Resins

Author ZhangXiaoNa
Tutor GaoJunGang
School Hebei University
Course Polymer Chemistry and Physics
Keywords Liquid crystalline diepoxides curing reaction kinetics thermal analysis mechanical properties
CLC TQ323.5
Type Master's thesis
Year 2009
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Three novel epoxy-terminated monomers were synthesized from different disruptors i n the central core. Their molecular structures were characterized by 1HNMR, FTIR, X RD,DSC and polarzing optical microscope (POM). The results show that the three co mpounds are all thermotropic liquid crystal. N,N-Bis[(4-(2,3-epoxypropoxy)-benzyliden)-4,4-diamino-diphenylether](BEPBDDE) and N,N-Bis[(4-(2,3-epoxypropoxy)-benzyliden)-4, 4-diamino-diphenylmethane] (BEPBDDM) are smectic mesophases, N,N-Bis[(4-(2,3-ep oxypropoxy)-benzyliden) phenylene-1,4-diamine] (BEPBPD) is nematic texture. The cur e kinetics of the three liquid crystal epoxy compounds with 4,4-diaminodiphenyl ether (DDE) was investigated by non-isothermal DSC method.The mixtures of the three liquid crystal epoxy resins with bisphenol-A epoxy resin (BPAER) were cured with a curing reagent of DDE, respectively. The curing processes, kinetics and thermal behaviors of those systems were investigated by DSC and torsional braid analysis (TBA).The morphological structure was measured by XRD, POM and SEM. The results show that the LC structure was fixed in the cured epoxy resin system. The impact strength and Tg were increased than that of the common bisphenol-A epoxy resin.The cure kinetics of liquid crystalline epoxy compound of p-phenylene di[4-(2,3-epoxypropyl) benzoate] (p-PEPB) with DDE was studied by non-isothermal DSC method. For the curing reaction, the initial temperature Ti, peak temperature Tp and finishing temperature Tf are 386K,409K and 430K, respectively. The average activation energy Ea was obtained by the isoconversional method of Ozawa. The reaction molecular mechanism was proposed. The co-curing reaction of p-PEPB with BPAER used DDE as a curing reagent was investigated by DSC.The results show that the p-PEPB and BPAER has well compatibility and can co-cure with DDE. The autocatalytic Sestak-Berggren model can describe the cure kinetics of the studied systems. The kinetics equation of p-PEPB/BPAER/DDE curing system is

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