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The decomposition of bisphenol A diglycidyl ether/alicyclic amine hardened networks in near-critical water was studied in this paper. It is possible to decompose thermosetting epoxy resin completely at 260 °C for 1 h with 1 g/5 ml feedstock ratio. The decomposition rate of epoxy resin increased with an increase in reaction temperature. The decrease in sample size led to higher decomposition rate, and the catalysts NH4 Cl and H2 SO4 had the higher positive effect on the decomposition rate. Thermogravimetry analysis (TGA) showed that thermal decomposition was not the primary factor for the collapse of networks in the temperature range studied. Gas Chromatography-Mass Spectrometry (GC-MS) showed the main components of the soluble decomposed compounds were bisphenol A, hydroxybenzene, olefin and ketone compounds and their content varied during the reaction. The hydrolysis of ether bond was regarded as the key factor in the process of decomposition reaction of bisphenol A diglycidyl ether/alicyclic amine hardened networks. [ABSTRACT FROM AUTHOR]

Chemical degradation of aramid/epoxy composites to the recycle of aramid fibers is presented in this article. 1,2,3,4-Tetrahydronaphthalene served as the main solvent decomposes the epoxy matrix and the virgin fibers are released under different decomposition conditions. The influence of reaction time, temperature, and feedstock ratio on the decomposition rate is investigated to ascertain the optimum condition of this recycle process. Gas chromatography mass spectrometry (GC-MS), single fiber tensile strength, and scanning electron microscope (SEM) are used to characterize the recycled fibers respectively, illustrating that aramid/epoxy composites can be decomposed successfully with this chemical method on the experimental condition. The hydrogenative mechanism of epoxy resin is also discussed tentatively according to the experimental result. [ABSTRACT FROM AUTHOR]

The cationic photoinitiator S,S-dialkyl-S-(3,5-dimethyl-4-hydroxyphenyl) sulfonium (called 4HPS simply) was synthesized in this article. The synthesis was proved successfully through FT-IR spectrum, 1H-NMR, and elemental analysis. The cure kinetics of photoinitiator/ ZH92-21 were studied through FT-IR spectrum combined with a high pressure mercury lamp. The concentrations of residual epoxy group, curing rate Rp and kinetics of polymerize termination were discussed. The results showed that the cure termination reaction of HPS photoinitiator/ZH92-21 was diradical-termination. [ABSTRACT FROM AUTHOR]

This study reports the method of recovery of glass fibers from glass/epoxy composites through the solvent method. It is possible to decompose epoxy resin with a yield of more than 99 wt% soluble products in a nitric acid solution (8 M) at 90°C for 5 h. The decomposition rate of epoxy resin increases with an increase in temperature and concentration of acid solution. The glass fibers can be recovered with very little contamination and they have a tensile strength reduction of 3.5% under decomposition conditions of T=70°C, t=250h, C=6M and α=6g/100mL. These fibers can be used as reinforcement to prepare new composites. The interlaminar shear strength (ILSS) of recovered short fiber-reinforced composites produce strength reductions of only 2.5% compared with pristine composites. [ABSTRACT FROM AUTHOR]