Characterisation and use of glass fibre reinforced plastic waste powder as filler in styrene-butadiene rubber

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.