The effects of residual solvent content, curing agent/ accelerator ratio, and hygrothermal aging on the curing behavior of the epoxy/dicyandiamide system.

• Main Authors: WU, CHANG SHENG, 吳長昇
• Other Authors: HONG S. G.
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/29283340088225782972

碩士 === 元智工學院 === 化學工程學系 === 85 === The effects of specimens configurations, residual solvents, curingagent/accelerators ratios, and hygrothermal aging on the curing behaviors ofan epoxy (diglycidyl ether of bisphenol A) and dicyandiamide (DICY)/2-methylimidazole system are studied with differential scanning calorimeter (DSC) andFourier transform infrared spectroscopy (FT-IR). In DSC analyses, the reactionexotherm (DH), the time to maximal cuing rate (tp), the glass trnsitiontemperature (Tg), the rate constant (k), and the reaction order (n)obtainedfrom the open cell system are all smaller than those from the close cell system. The differences are confirmed with FT-IR results in which a variation in curedstructures are observed in specimens from two configurations. The curingcharacteristics are also changed by the presence of residual solvent in theepoxy system. The changes are in the order of toluene > tetra-hydrofuran > acetoneand which are consistent with the order of boiling temperatures. The result fromDSC and FT-IR analyses indicate that the DICY/2-MI ratio applied also affectsthe curing kinetics and curing structures of the resin system because the complextemperature dependent curing reactions are affected differently by the changesin reaction rates and reacting probabilities of functional groups. In addition,the hygrothermal aging of epoxide function groups results in a decrease of DH butan increase of tp.