A novel novolac curing agent containing both naphthalene and dicyclopentadiene （DCPD） moieties was prepared to produce a highly heat-resistant cured polymer network. The chemical structure was characterized using Fourier transform infrared spectroscopy, nuclear magnetic resonance, mass spectrometry, and gel permeation chromatography analyses. The thermal properties of the resulting polymer from diglycidyl ether of bisphenol A epoxy resin cured with the novel curing agent were evaluated using dynamic mechanical thermal analysis and thermogravimetric analysis. Compared with the conventional curing agent, the resulting polymer cured with naphthalene/DCPD navolac shows considerable improvement in heat resistant properties such as higher glass transition temperature （Tg） and thermal stability. The result also shows better moisture resistance because of the hydrophobic nature of naphthalene/DCPD structure. 相似文献
Abstract Six modified bismaleimide (BMI) resin systems are developed. The modifier is diallyl bisphenol A, diallyl bisphenol A ether. TDE-85 epoxy/MNA anhydride, and styrene. respectively. In view of structure of those cured resins, relationships between structure and dielectric properties have been studied emphatically, while effects of postcure temperature and catalysts on dielectric properties were also shown. Results indicate that dielectric properties lie on structure of cured resin and postcure temperature; catalysts can strikingly improve the heat-resistance of materials, but has little effect on the dielectric properties. In addition, mechanical and thermal properties of neat resins were also shown. 相似文献
We have synthesized a series of epoxy resins containing melamine phosphate (MP) and investigated their thermal and flame retardation properties. MP functions as a hardener and a flame retardant or as an additive of the cured epoxy resin to enhance flame retardation properties of epoxy resins. The reactions of DGEBA cured in the presence of MP were monitored by NMR and FTIR. Our results show that in both reactive and additive modes, MP is effective in increasing limiting oxide index (LOI) and the char yields of epoxy resins at lower phosphorous content. We observed that flame retardation by MP in its reactive mode is better than in its additive mode; the same phenomenon was found also for the glass-transition temperature (Tg). Thermogravimetric analysis (TGA) demonstrated that epoxy resins containing MP decompose at relatively lower temperatures than those lacking MP; this decomposition results in a protective layer forming that prevents the epoxy resins from decomposing further by combustion. 相似文献
The effect of catalyst content on the thermal and mechanical properties of diglycidyl ethers of bisphenol A (DGEBA)/BPH system was investigated at elevated temperatures. The contents of the catalyst, N‐benzylpyrazinium hexafluoroantimonate (BPH), examined were 0.5, 1, and 3 wt.‐% and the elapsed heating time was varied from 0 to 1 024 h. As a result, the thermal‐oxidative resistance and mechanical properties, including flexural strength, elastic modulus in flexure, and impact strength showed a maximum value at 1 wt.‐% BPH. By increasing the elapsed time to 4 h, the thermal and mechanical properties of the specimens were also improved. These results showed that the internal structure of the epoxy system was stabilized and post‐cured as the elapsed time increased, resulting in an improvement of the thermal and mechanical properties of the specimens.
Impact strength of the DGEBA/BPH system as a function of BPH content and elapsed heating time. 相似文献
