The interfacial shear strength (IFSS) is commonly used for evaluating the adhesion at the interface between fibre and matrix. A glass fibre/epoxy matrix system was investigated. The surface coatings applied to glass fibres may result in a discrepancy in the amine:epoxide group ratio between the interface and the bulk matrix, consequently moving the ratio away from the optimum stoichiometric ratio most often used. The amine:epoxide group ratio in the matrix was varied to obtain the optimum ratio at the interface. The study found that the amine:epoxide ratio influenced the IFSS with an optimum just below the stoichiometric ratio. The microbond test was conducted in a thermal mechanical analyser (TMA) to determine the IFSS thus revealing an inverse dependency on the testing temperature: an increased testing temperature yields a decrease of IFSS. IFSS determined at temperatures below the glass transition temperature displays a decreasing trend at high amine:epoxide ratio whereas IFSS measured at testing temperatures above the glass transition temperature steadily increases as the amine:epoxide ratio increases. The microbond test was conducted using both a tensile tester and a TMA setup. The two microbond test setups yielded results with same behaviour of the IFSS as a function of the amine:epoxide ratio.
- adhesion and bonding
- stress transfer mechanism
Petersen, H. N., Minty, R. F., Thomason, J. L., Yang, L., Kusano, Y., Brønsted, P., & Almdal, K. (2018). The amine:epoxide ratio at the interface of a glass fibre/epoxy matrix system and its influence on the interfacial shear strength. Composite Interfaces, 1-13. https://doi.org/10.1080/09276440.2018.1511107