Dielectric analysis monitoring of thermoset curing with ionic liquids: From modeling to the prediction in the resin transfer molding process. Issue 12 (28th May 2019)

• Record Type: Journal Article
• Authors: Demleitner, Martin; Sanchez‐Vazquez, Sandra Aline; Raps, Daniel; Bakis, Gökhan; Pflock, Tobias; Chaloupka, Alexander; Schmölzer, Stefan; Altstädt, Volker
• Is Part Of: Polymer composites. Volume 40:Issue 12(2019)
• Page Start: 4500
• Page End: 4509
• Publication Date: 2019-05-28
• Subjects: activation energy -- curing of polymers -- thermosets -- modeling; Polymeric composites -- Periodicals; 620.192
• DOI: 10.1002/pc.25306
• Languages: English
• ISSNs: 0272-8397

Abstract

Abstract: The aim of the present work was to establish a cure‐prediction via dielectric analysis (DEA) for a bisphenol A diglycidyl ether (DGEBA) epoxy cured with an imidazolium‐based ionic liquid [EMIM][N(CN)2 ]. Ionic liquids caught increasingly attention in the composite industry due to their potential use as efficient latent curing agent and hence possible optimization of production cycles. Dielectric analysis is a promising tool for mass‐scale composite production for monitoring cure and as feedback control system, however a profound correlation to thermal and rheological properties is necessary. For this purpose, complementary cure kinetic modeling of the neat system was first carried out via differential scanning calorimetry (DSC) to allow the prediction of the degree of cure and glass transition temperature T g during the curing cycle. The focus laid on the comparison between isoconversional and model‐based prediction and the influence of the implementation of the diffusion factor. Dielectric measurements were conducted and afterwards a cure prediction based on these results was established. Problems with ionic liquids as curing agent along with using DEA as characterization method were addressed. Consequently, to verify the previously obtained outcome, dielectric analysis was conducted to real‐time monitor the crosslinking during the resin transfer molding (RTM) process. Sufficient agreement to theoretical cure prediction based on DSC and DEA results with actual conversion during RTM was observed.