抄録
There are three kinds of interfaces in FRP: fiber/matrix, matrix/matrix and FRP/FRP interfaces. Since these interfaces are aligned in a series in the flatwise direction of FRP, the individual property of the interface or the relation among the three interfaces can be evaluated by applying tensile load in this direction.
In this paper, the relation between the fiber/matrix and the FRP/FRP interfaces and its dependence on matrix were studied by this method in the temperature range from -40°C to 120°C. Two types of matrices selected were unsaturated polyester resins which show obvious difference in their adhesiveness and thermal properties. The reinforcement was roving glass cloth. The fiber/ matrix ratio and the condition of heat treatment (FRP/adhesive) were changed. The results obtained are as follows.
(1) The temperature dependence of the brittle or ductile behavior of the interface was not affected by the location of the weakest interface. But it was changed by the thermal properties of the matrix which depended on the condition of heat treatment.
(2) The temperature dependence of the location of the weakest interface was affected by the fiber/matrix ratio. The location of the weakest interface changed also with the type of matrix and the condition of heat treatment.
(3) The temperature dependence of the bond strength was affected by the fiber/matrix ratio. The bond strength varied with the type of matrix, the condition of heat treatment and the location of the weakest interface.
(4) In the case of the fiber/matrix ratio=100/0, the bond strength changed with the temperature dependence of the bond strength. On the other hand, in the case of the fiber/matrix ratio=0/100, the bond strength changed with the temperature dependence of the location of the weakest interface.
