MONITORING OF AGING OF AN OUT-OF-AUTOCLAVE PREPREG USING DIFFERENTIAL SCANNING CALORIMETRY

摘要

Recent advances in prepregs have enabled oven curing to achieve high quality parts at lowerrntemperature compared to autoclave curing. In aerospace applications, multiple rolls of prepregrnare often used to manufacture large parts and the material may remain outside several daysrnduring fabrication. As such, it is always a concern that the part’s quality could be affected due tornmaterial aging during out-time under ambient conditions. Although the reaction is morernprogressive at elevated temperature, extended out-time at lower temperature could also build uprnproblems, such as decrease in tackiness and processability of prepreg. In this paper, a differentialrnscanning calorimeter was utilized to study aging progress of an out-of-autoclave prepreg. It wasrnobserved that the sub-ambient glass transition temperature and percent of conversion due tornaging increased proportionally with out-time of prepreg. Additionally, total heat of reaction, peakrntemperature, and activation energy were decreased as out-time increased.