The Effect of Time and Temperature on the Flexural Strength of a Silica Particle Filled Epoxy Resin

Abstract

Composite materials that use an epoxy as a matrix resins have superior mechanical properties but these materials exhibit time and temperature behavior when used for long periods and under high temperatures. This time and temperature behavior has not been fully explained. The purpose of this paper is to further describe this time and temperature behavior, therefore increasing the reliability of these types of composite materials. The time and temperature dependence of flexural strength was examined by flexural static and fatigue testing. Initially the neat resin's viscoelastic mechanical behavior was determined experimentally to be later compared to the composites. Static tests were carried out at various constant deflection rates and temperatures below the glass transition temperature of the epoxy resin. It was shown that the time-temperature superposition principle is applicable for the flexural static strength. Comparison of the neat resin and the composite results show that the neat resin is a major influence on the time and temperature behavior of the composite materials static strength behavior. Fatigue tests were carried out at several stress ratios and various temperatures below the glass transition temperature of the matrix resin. It was shown that the time-temperature superposition principle is applicable for the initial flexural fatigue strength by using the time-temperature behavior of the matrix resin. As temperature and stress ratio increased, the creep influence increased in both the flexural strength and the modulus.

Fatigue life predictions in polymer particle composites

“…McMurray and Amagi [3] studied the effect of temperature and stress ratio on fatigue strength of a silica-filled epoxy resin. They studied only one volume fraction (60%) of silica with an average size of 7 µm.…”

Retardation and repair of fatigue cracks in a microcapsule toughened epoxy composite – Part I: Manual infiltration

“…Susceptibility to cyclic loading is particularly problematic because a crack will grow, however slowly, above a threshold range of stress intensities ΔK th that is significantly lower than the critical stress intensity K IC . Prevention of fatigue failure currently depends on accurate life prediction and implementation of inspection procedures.Polymer fatigue has been studied extensively in both homogeneous and composite structures (e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]). In most polymers, fatigue crack growth rates (da/dN) are accurately described by the Paris power law [16],…”

“…reduce n, and (d) increasing the threshold ΔK th at which crack growth arrests. In the case of brittle thermosetting polymers, incorporation of a rubbery second phase [8][9][10], solid particles [11][12][13] or microcapsules [14,15] significantly improves fatigue performance by increasing the fracture toughness (Fig. 1a) and decreasing the Paris power law exponent (Fig.…”

Mechanical Behaviors Study of Epoxy Resins Reinforced with Nano-SiO2 Particles

“…There is a keen interest to clarify the relevance of the primary properties of SiO 2 particles on the rheological characteristics of the composite system [1][2][3][4]. The study found that, the mechanical property of epoxy resin can be improved by the addition of nanoparticles in the epoxy resin.…”