Successful closed-loop recycling of thermoset composites

Re-use assessment of thermoset composite wastes as aggregate and filler replacement for concrete-polymer composite materials: A case study regarding GFRP pultrusion wastes

“…Relevant properties of the recyclates that will affect the performance of the final composite are dictated by these key operations. This feature is also stressed in Rikards et al (1994) and Palmer et al (2009), some of the few thorough investigations that take into consideration fibre and filler fractions, various combinations of recyclate grades and replacement percentages. With a well-designed combination of powder and fibre fractions, better properties on the final composites could be achieved due to a better packing of overall aggregate system, without compromising both workability and wettability of the mixture.…”

“…Filler or reinforcement material for artificial wood (Demura et al, 1995), high density polyethylene plastic lumber (George and Dillman, 2000), wood particle board (Conroy et al, 2006), rubber pavements blocks (Itoh and Kaneko, 2002), cement based concrete materials (Asokan et al, 2009(Asokan et al, , 2010Correia et al, 2011;Kojima and Furukawa, 1995;Osmani and Pappu, 2010;Tittarelli and Moriconi, 2010;Wakasuhi and Sugiura, 1995;Yamada k Mihashi, 1995), bulk and sheet moulding compounds (DeRosa et al, 2005a(DeRosa et al, , 2005bJutte and Graham, 1991) and core material for textile sandwich structures (Adolphs and Branca, 2001), were some of the foreseen potential applications for the recyclates. Most of them have failed at an industrial scale due to one or both of the following reasons: (a) tendency of recyclate addition to negatively affect the mechanical properties of final composite; and (b) negative cost balance, where recycling and refining operation costs outweighed the market value of the virgin products (calcium carbonate and glass fibres); (Halliwell, 2006;Palmer et al, 2009;Pickering, 2006).…”

“…Ensuring that feasible market outlets exist, mechanical recycling is so far considered the favoured recovering technique, at least for relative low cost and clean GFRP waste materials (Palmer et al, 2009;Pickering, 2006). However, mechanically recycled GFRP wastes have not been yet reflected in industry market mainly due to a lack of cost-effective end-use applications for the recyclates, and clearly developed recycling routes (logistics, infrastructures and recycling facilities) between waste producers and potential consumers for the recyclates (Conroy et al, 2006;Palmer et al, 2009;Pickering, 2006). Higher value end markets need to be identified for the recyclates.…”

An integrated recycling approach for GFRP pultrusion wastes: recycling and reuse assessment into new composite materials using Fuzzy Boolean Nets

“…Most of them have not succeeded for one or both of the following rea-sons: a) tendency of the recyclate addition to negatively affect the mechanical properties of final composite; and b) negative cost balance, where mechanical recycling and sorting operational costs outweighed the market value of the virgin product (chop-ped glass fibres and calcium carbonate) (Halliwell, 2006;Palmer et al, 2009).…”

“…Nevertheless, GFRP products obtained by pultrusion process do not contain promoter, only initiator, as polymerisation reaction is induced by tempera-ture; hence, risk of fire during mechanical recycling process of these materials is avoided. Guaranteeing that viable markets out-lets exist for the recyclates, mechanical recycling could be considered as the most cost-effective recycling technique, at least for relatively low-cost and clean GFRP waste materials proceeding from promoter-free manufacturing processes (Palmer et al, 2009;Pickering, 2006).…”