IN-PROCESS CONTROL OF EPOXY COMPOSITE BY MICRODIELECTROMETRIC ANALYSIS - PART II - ONLINE REAL-TIME DIELECTRIC MEASUREMENTS DURING A COMPRESSION MOLDING PROCESS

The curing of a fiberglass epoxy composite based on diglycidyl. ether of bisphenol A (DGEBA) with dicyanodiamide (DDA) as the hardener and i midazole as the catalyst agent was analyzed using microdielectrometry, The curing behavior of thick epoxy composite parts was examined in a production environment for compression molding process; The particular focus of this paper is to present the method used to collect on-line real-time conversion measurements during an epoxy/fiberglass composite cure. For this purpose, temperature and ionic conductivity profiles d uring industrial moldings of a thick epoxy part were recorded. Corresp onding conversion profiles were deducted from a previous empirically e stablished correlation and discussed in terms of cure gradients as a f unction of the through-the-thickness location and of the cure cycle ti me.