Low moisture absorptive epoxy formulations for Gr/Ep laminates

• Published in: Polymer composites 1999-06, Vol.20 (3), p.472-481
• Main Authors: Lin, King-fu, Yeh, Ren-jie
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Forms of application and semi-finished materials; Laminates; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0272-8397; 1548-0569
• DOI: 10.1002/pc.10371

The incorporation of 2‐undecyl‐imidazole (C11Z) and chromium acetylacetonate (Cr(acac)3) additives into N, N, N′, N′‐tetraglycidyl diaminodiphenylmethane (TGDDM)/diaminodiphenylsulfone (DDS) epoxy formulations was found to significantly decrease the moisture absorption of their prepared graphite/epoxy laminates. However, the same additions did not much affect the moisture absorption of the cured TGDDM/DDS neat resins. Thus, the former case was attributed to the processing effects in view of the fact that C11Z pre‐reacting with TGDDM during lay‐up process produced the ether‐linkage polymer chains in the epoxy networks and raised the viscosity. The following compacting stage of laminates was believed to squeeze the small molecules such as unreacted TGDDM, DDS and Cr(acac)3, toward the surface of carbon fibers and increase the chance of Cr(acac)3 to block the hydroxyl groups in the epoxy networks produced by the reactions between TGDDM and DDS. Some evidence was provided to support the above hypothesis in this study.