Toughening mechanism of epoxy modified with CTBN elastomer adhesive j oints

Authors: Ochi, M.; Mimura, K.; Motobe, H.

Source: Journal of Adhesion Science and Technology, Volume 8, Number 3, 1994 , pp. 223-233(11)

Buy & download fulltext article:

Price: $35.00 plus tax (Refund Policy)

Abstract:

The effect of modification with CTBN on the bonding properties of an epoxy system cured with 1-o-tolylbiguanide (TBG) was investigated and compared with the results of the system cured with ethylenediamine (EDA). TBG was used as a model of dicyandiamide, which is a typical latent curing agent. The bond strength and toughness of the TBG-cured system increased considerably with the addition of the CTBN modifier, whereas the values for the EDA-cured system were not influenced by the modification. In the former system, cavitation of the CTBN-dispersed phase and plastic deformation of the epoxy matrix were observed in the vicinity of the crack tip. These phenomena were not observed in the EDA-cured system. In addition, the crosslink density of the TBG-cured system was much lower than that of the EDA-cured system. Thus, it was concluded that the high bond strength in the TBG-cured system modified with CTBN is caused by cavitation and also by shear yielding of the low-crosslinked epoxy matrix.

Keywords: Epoxy resin; dicyandiamide; adhesive property; toughening mechanism; adhesive joints

Document Type: Research article

DOI: http://dx.doi.org/10.1163/156856194X01077

Affiliations: 1: Department of Applied Chemistry, Faculty of Engineering, Kansai University, Osaka, 564, Japan

Publication date: 1994-01-01