Recycling of thermoset fiberglass by direct molding of ground powders

Fiberglass production in western Europe exceeds one million tons per year, and data of the European Commission inform that at their end-of-life, 25% of waste fiberglass is sent to landfill. Being a thermosetting material, it polymerizes during its production, when a molecular network is generated into the matrix. This network is responsible for its optimal properties, but it prevents the material flow under heating and thus reprocessing. A new recycling process for fiberglass waste has been proposed by the authors without any use of virgin materials or additives. This technology consists of a direct molding (i.e., compression molding) of pulverized fiberglass. The material agglomeration depends on the combination of several mechanisms, from residual reactivity, to powder re-activation and incipient degradation during molding. Residual fiberglass powder has been recovered from a factory that specializes in technical laminates, where a grinding process is used to provide the expected tolerance to the products. The recovered powder has been direct molded to manufacture small samples for mechanical testing. Such powder shows thermal activation in the DSC (differential scanning calorimetry) at low temperature (about 80°C). This study shows the feasibility of recycling waste fiberglass without using any virgin material; these new findings are related to the use of industrial powders, their testing under 4-point bending and the obtaining a good, molded surface.