Glass fibre reinforced plastic (GRP) wastes are often disposed of in landfill,
incinerated or processed into powders. GRP waste powders can be recycled as filler in
virgin polymers and should be characterised before they are added to avoid processing
problems. A GRP waste powder was characterised using advanced measuring and
analytical techniques. These included, scanning electron microscopy, Fourier
transform infrared spectrometry, particle size analyser, differential scanning
calorimetry, X-ray photo-electron spectroscopy and energy dispersive X-ray
microanalyser. The results showed that the waste powder consisted of irregular
shaped particles and glass fibre fragments up to 700 m in size. Moreover, the waste
powder was a thermoset polyester resin and its chemical constituents were calcium,
oxygen, aluminium, silica, chlorine, bromine and carbon. When up to 25 parts per
hundred rubber by weight of the GRP waste powder was mixed with a sulphur cure-
based styrene-butadiene rubber, the viscosity, scorch and optimum cure times
increased, and the rate of cure decreased. The tearing energy, elongation at break,
tensile strength, stored energy density at break, and Young’s modulus of the
vulcanisate improved as the loading of the waste powder was raised