Jabalkumar D Thanki and Parsotam H Parsania
Marwadi University, India
Saurashtra University, India
Posters & Accepted Abstracts: J Material Sci Eng
Dynamic DSC curing kinetics of epoxy resin of 9,9'-bis(4-hydroxyphenyl) anthrone-10 (EAN) was carried out at 5o, 10o, 15o and 20o min-1 heating rates in nitrogen atmosphere using 4,4'-diaminodiphenyl sulfone (DDS), 4,4'-diaminodiphenyl methane (DDM) and tetrahydrophthalic anhydride (THPA) hardeners. Peak exotherms shifted towards higher temperature range with increasing heating rate. DSC data were analyzed by Ozawa, Kissinger and Flynn-Wall-Ozawa methods to derive activation energy (Ea) and frequency factor (A). Observed trend in Ea and A is EAN-DDS > EAN > EAN-THPA > EAN-DDM. For EAN-amine systems both Ea and A decreased with increasing conversion and for EAN-THPA they increased up to 30% conversion and then decreased slowly with increasing conversion. Friedman plots showed autocatalytic nature of the EAN-hardener systems. Autocatalytic nature is due to dehydration of secondary alcohol groups with simultaneous formation of allylic double bonds. Thermogravimatric study at 10oC min-1 heating rate in nitrogen atmosphere revealed that cured resins (3100c-3370c) are more thermally stable than thermally cured EAN (2790c) and followed either one or two step degradation kinetics.
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