Isothermal Cure of anEpoxy System Containing Tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM), a Multifunctional Novolac Glycidyl Ether and 4,4′-Diaminodiphenylsulphone (DDS): Vitrification and Gelation

✍ Scribed by Barral, L.; Cano, J.; López, J.; Nogueira, P.; Ramírez, C.; Abad, M. J.

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 330 KB
• Volume: 42
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199703)42:3<301::aid-pi714>3.0.co;2-f

✦ Synopsis

Times to gelation and vitriÐcation have been determined at di †erent isothermal curing temperatures between 200 and 240¡C for an epoxy/amine system containing both tetraglycidyl-4,4@-diaminodiphenylmethane (TGDDM) and a multifunctional Novolac glycidyl ether with 4,4@-diaminodiphenylsulphone (DDS). The mixture was rich in epoxy, with an amine/epoxide ratio of 0É64. Gelation occurred around 44% conversion. VitriÐcation was determined from data curves of glass transition temperature, versus curing time obtained from T g , di †erential scanning calorimetry experiments. The minimum and maximum values determined for this epoxy system were and T g T g0 \ 12¡C T gmax \ 242¡C. Values of activation energy for the cure reaction were obtained from versus T g time shift factors, and gel time measurements. These values were, respectively, a T , 76É2 kJ mol~1 and 61É0 kJ mol~1. The isothermal timeÈtemperatureÈ transformation (TTT) diagram for this system has been established. VitriÐcation and gelation curves cross at a cure temperature of 102¡C, which corresponds to glass transition temperature of the gel.