| The emerging of polyhedral oligomeric silsesquioxane (POSS) organic-inorganic hybrid nanocomposites that combine the processibility and flexibility of typical organic thermoplastics with high service temperature and oxidation resistance of inorganic ceramics, has received great attentions recently. Generally, POSS cages which have the precise three-dimension size, can be incorporated into epoxy molecular network via copolymerization or grafting polymerization to improve the thermal properties and oxidation resistance of epoxy systems.In this paper, the triglycidyl p-aminophenol epoxy resin (AFG-90) was first modified by trisilanolphenyl polyhedral oligomeric silsesquioxanes (TSP-POSS) and then cured by two kinds of curing agents, 3-(or 4)- methyl-tetrahydrophthalic anhydride (MeTHPA) and 4,4'-diamino-diphenyl-sulfone (DDS), respectively. According to the thermal propertites of epoxy systems modified with TSP-POSS via differents technics, the proper modification technics is that TSP-POSS can be properly dispersed in AFG-90 resin by ultrasonic, the pre-reactive time of AFG-90 resin and TSP-POSS is 15 hours, and the loadings of catalyst triethylamine (TEA) of AFG-90/MeTHPA system is 0.3 wt%, while TEA is not compatible with the AFG-90/DDS system.The investigation of curing kinetics of modified epoxy systems indicates that the studied curing process can be described by the two-parameter expended Prout-Tompkins kinetic model with autocatalysis. The molecular structures of AFG-90/MeTHPA system and AFG-90/DDS system were characterized by Fourier transform infrared spectroscop. The results show that epoxy groups disappeared after cured by MeTHPA or DDS, ester and tertiary amine structures were formed, accordingly, while the structures of TSP-POSS cages were not destroyed. Phase separation was not observed in the epoxy systems modified by TSP-POSS by scanning electronic microscopy, except for the AFG-90/DDS system with TSP-POSS content of 10wt %.The thermal and mechanical properties of the epoxy systems modified by TSP-POSS were also measured. It shows that the glass transition temperature, thermal deformation temperature, the thermal dimensional stability, and bending storage module E of Epoxy/TSP-POSS increased with increasing content of TSP-POSS, while the thermal expansion coefficient and tanδpeak intensity decreased. The maximal enhancement of glass transition temperature of AFG-90/ MeTHPA system and AFG-90/DDS system were 23.80℃and 22.78℃, respectively. However, the flexural strength, tensile strength and breaking extension of Epoxy/TSP-POSS decreased with increasing content of TSP-POSS, while the flexural module and tensile module increased.Furthermore, the chemo-rheology investigation indicates that the viscosity of AFG-90 resin was greatly increased after modified with TSP-POSS, and the present of TSP-POSS in AFG-90/ MeTHPA had little influence on the initial viscosity, but no evidence was found that it had influence on the viscosity at the initial reaction stage. A rheological model based on dual-Arrhenius equation was established and used to simulate chemo-rheological behavior of the AFG-90/MeTHPA/TSP-POSS system. The viscosity estimated by the model was in good agreement with that of the experiment results at the initialization reaction stage. The rheological model shows that the optimum processing temperature of the resin system for RTM process is between 20℃and 30℃.
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