Influence of aging and wetting on dynamic mechanical properties of multi-functional epoxy resins filled with pitch-based carbon short fibers

• Published in: Advanced composite materials 1998-01, Vol.7 (2), p.117-135
• Main Authors: Yamaguchi, Muneaki, Tanaka, Yuko, Tanaka, Katsutoshi
• Format: Article
• Language: English
• Subjects: aging; composite materials; dynamic mechanical properties; Multi-functional epoxy resin; pitch-based carbon short fiber; wetting
• ISSN: 0924-3046; 1568-5519
• DOI: 10.1163/156855198X00093

Pitch-based carbon and graphite short fibers (PCF and PGF) as functional filler materials were filled in multi-functional epoxy resin (EP) using five types of hardeners with 22.2 wt%. Influence of aging and wetting on dynamic mechanical properties of these materials was measured by the use of the nonresonant forced vibration method. Aging of the specimens were carried out at 130°C for 5000 h and wetting was carried out at 21°C in distilled water for 5000 h. The longer the aging time, the less the weight of the specimens which reached a maximum was 5.3 wt% after 5000 h. The glass transition temperature (T g ) for all the specimens increased. The storage moduli (E') for the aged specimens did not change much at low and room temperatures compared with those for the unaged specimens (UA) but they increased at high temperatures. The maximum wetting rate of the specimens was 5.1 wt% and the values of T g decreased for all the specimens. The values of E' increased in the range from a low temperature (-140°C) to a room temperature (25°C) but they decreased at a high temperature (200°C). This tendency was more significantly observed in specimens cured with diamine hardeners than specimens cured with acid anhydrous hardeners.