سال انتشار: ۱۳۹۰
محل انتشار: کنفرانس بین المللی فرآورش پلیمرها
تعداد صفحات: ۴
Mahdieh Shervin – Iran Polymer and Petrochemical Institute, P. O. Box: 14975/112, Tehran, Iran
Mohammad Hosain Beheshty –
Epoxy resins are widely used in different applications. Dicyandiamide (DDA) cured epoxy resin is a matrix system which is being used in manufacturing of structural composites. The structure property relationship in curing of epoxy resin by DDA is an important matter which it is not being extensively studied. In this paper, therefore, the curing and properties of three commercially available epoxy resins including LY564, LY5052 and LY 5210 were studied by using required molar ratio of DDA curing agent and 2phr monurone accelerator. The epoxy resins were characterized using FTIR, 1HNMR and 13CNMR spectroscopy. The curing beha-vior of epoxy-DDA systems was studied by differential scanning calorimetry. The mechanical properties of these systems where measured by lap shear tests. Characterization results showed that LY564, LY5052 and LY 5210 are based on diglycidyl ether of bisphenol A, 4,4′ –tetraglycidyl diamine diphenol methane (TGDDM) and novolak epoxy resin structures, re-spectively. Thermal analysis revealed that the peak curing temperature of all systems were 156±۱ºC and LY5210-DDA system has the highest Tg (140ºC) among the studied epoxy re-sins. The LY5052 had the highest (237J/g) and LY564 had the least (180J/g) heat of curing reactions. The lab shear strength of LY564, LY5052 and LY5210 DDA cured systems were 14.8, 12.6 and 10.8 MPa, respectively. Thermal properties and lap shear strength are attri-buted to the network epoxy structure of the cured structure of the epoxy matrix.