Styrene emissions during gel-coating of composites

The manufacture of fibre-reinforced polymer matrix composites may release potentially harmful volatile organic compounds into the workplace and the environment. Styrene, in unsaturated polyester or vinyl ester resins, can be a significant source of emissions especially in open mould processes. The styrene monomer is implicated in a number of health issues. This paper compares conventional hand-painted gel-coating, in-mould gel-coating and in-mould surfacing processes to establish if styrene levels can be significantly reduced by the adoption of closed mould systems. The conventional hand-painted technology was found to have significantly higher levels of styrene emission than the two closed mould processes. For the open mould process, the average styrene levels were in the range 28-70 ppm. The two closed mould technologies significantly reduce the measured styrene levels to lie in the range 0.23-0.37 ppm. The new processes offer a reduction in average styrene emission levels of >98% (worst new/best old) with obvious benefits for worker health and the reduction of environmental burdens.