Depolymerization of thermosetting epoxy resin with environmental-friendly heteropolyacid catalyst at temperatures between 270°C-350°C in H2O medium. The effect of the factors catalyst, temperature and time on the depolymerization was researched. UV spectrum was used to characterize the thermal stability of heteropolyacid catalyst. The products of depolymerization were analysed qualitatively and quantitatively by means of GC/MS and GC. The results indicated that the main depolymerized products were phenol, p-isopropylphenol and bisphenol-A (BPA). The results showed adding heteropolyacid contribute to enhancing the rate of depolymerization and increasing the yield of BPA. Also, the depolymerization kinetics of epoxy resin was researched and the activation energy was calculated.
Hydrothermal depolymerization of DGEBA/EDA epoxy resin was carried out in a stainless autoclave at temperatures of 270°C to 350°C in H2O medium. The effect of the factors catalyst, temperature and time on the depolymerization was researched. The products of depolymerization were analyzed qualitatively and quantitatively by means of GC/MS and GC. The results indicated that the main depolymerized products were phenol, p-isopropylphenol and bisphenol-A (BPA). The epoxy resin composite based on glass fiber and the solid residue after reaction using catalytic hydrothermal depolymerization technology were analyzed by SEM. Also, the depolymerization kinetics of epoxy resin with 3% catalyst and no catalyst were researched and the activation energy was calculated.
The activated carbon was prepared by the two-steps carbonization-activation process with printed circuit board (PCB), using KOH, K2CO3, NaOH and Na2CO3 as activators. The influence of temperature, reaction time and the ratio between activator and material on methylene blue value was discussed. Box-behnken design was applied using Design-Expert software to optimize the conditions of preparation according to Response Surface Methodology (RSM).Results showed that activated carbon prepared by chemical activation with KOH or NaOH achieved higher adsorption of methylene blue.
Poly (ethylene-co-tetrafluoroethylene) (ETFE) membranes were irradiated by electron beams and then acrylic acid (AA) and sodium styrene sulfonate (SSS) were grafted onto the membranes, in an attempt to prepare cation exchange membranes containing -COOH and -SO3Na groups. The grafting yield was found to be strongly dependent on the synthesis condition such as irradiation dose, co-monomer composition. Infrared spectroscopy of the grafted membrane confirmed the existence of sulfonate and carboxylic acid groups. The membrane resistance decreases with the increasing of grafting yield
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