The Effect of Resin Formulation on the Surface Appearance of Glass Fiber Reinforced Polymers

Abstract

This paper is concerned with the effect of resin formulation on the magnitude of fiber readout for polymers reinforced with continuous glass fiber mats. The observed fiber readout is the deformation of the surface with a pattern similar to the underlying fibers. In our previous studies, it was established that one of the main factors responsible for fiber readout is the coefficient of linear thermal expansion (CLTE) of the resin in the direction normal to the cosmetic surface. In the current study, the differential thermal contraction (Δ∈) between the resin and the glass fibers, a factor directly relatable to the magnitude of fiber readout, has been investigated. This direct relationship was examined by comparing the computed values for the Δ∈ with the measured magnitude of fiber readout for rein forced polyurethanes (filled with milled glass or hollow glass spheres) and polyesters (filled with calcium carbonate). For all experiments, the predicted values for (Δ∈) were found to be consistent with the experimental measurements for fiber readout.