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Glass fiber-reinforced polyester composite (GFRPs) scraps from manufacturing of polyester laminates were pyrolyzed at 500, 550 and 600°C in an 70 Kg innovative batch pilot plant that processes whole parts. The presence of a hydraulic guard guarantees the safety of the process. The influence of the maximum process temperature on yields and chemical-physical properties of pyrolysis products was investigated: the oil fraction was analysed by GC-MS, Viscometer and XRF, while the gas fraction was monitored online during the entire pyrolysis process by µ-GC. Substantial fractions of methane (20.7 vol %) and hydrogen (11.5 vol %) were produced. The solid residue (glass fibers covered by a thin carbonaceous layer) underwent an oxidative process at 500 and 600°C at different residence times to provide clean glass fibers free of organic residues. The effects of both pyrolysis and oxidative step on the glass fibers, obtained in different process conditions, were evaluated by SEM and Raman spectroscopy.

This work focuses on the optimization of pyro‐gasification process of carbon fiber reinforced polymers (CFRPs) with the aim of recovering carbon fibers (CFs) with properties suitable for the production of new more sustainable composites with high performances. In particular, the pyro‐gasification process is carried out on cured CFRPs panels based on both epoxy (EC) and vinyl ester (VC) matrices, which are the two most used resins for CFRPs. The matrix degradation is evaluated via sample's weight loss measurement and the recovered CFs obtained after different time of treatment are analyzed to identify convenient pyro‐gasification conditions to avoid damaging of the recovered CFs. The obtained results highlight the importance of the thickness of the composites to be treated for the identification of the more suitable pyro‐gasification conditions. [ABSTRACT FROM AUTHOR]

Carbon-fiber-reinforced polymers (CFRPs) are increasingly used in a variety of applications demanding a unique combination of mechanical properties and lightweight characteristics such as automotive and aerospace, wind turbines, and sport and leisure equipment. This growing use, however, has not yet been accompanied by the setting of an adequate recycling industry, with landfilling still being the main management route for related waste and end-of-life products. Considering the fossil-based nature of carbon fibers, the development of recovery and recycling technologies is hence prioritized to address the environmental sustainability challenges in a bid to approach mitigating the climate emergency and achieving circularity in materials' life cycles. To this aim, we scaled up and tested a novel semi-industrial pilot plant to pyrolysis and subsequent oxidation of uncured prepreg offcuts and cured waste of CFRPs manufacturing. The environmental performance of the process proposed has been evaluated by means of a life cycle assessment to estimate the associated carbon footprint and cumulative energy demand according to three scenarios. The scale-up of the process has been performed by investigating the influence of the main parameters to improve the quality of the recovered fibers and the setting of preferable operating conditions. The pyro-gasification process attested to a reduction of 40 kgCO2eq per kg of recycled CFs, compared to virgin CFs. If the pyro-gasification process was implemented in the current manufacturing of CFRPs, the estimated reduction of the carbon footprint, depending on the composite breakdown, would result in 12% and 15%. This reduction may theoretically increase up to 59–73% when cutting and trimming waste-optimized remanufacturing is combined with circular economy strategies based on the ideal recycling of CFRPs at end-of-life. [ABSTRACT FROM AUTHOR]

New and end of life tires have been pyrolyzed in an innovative pilot plant that processes whole tires, thus saving the energy costs of shredding while allowing energy and materials recovery. Furthermore, the presence of a hydraulic guard guarantees high process safety. Several tests at different temperatures have been performed and the collected solid, liquid and gaseous products have been quantified and characterized. The influence of the maximum process temperature on yields and chemical-physical properties of pyrolysis products has also been evaluated. In view of a plant scale-up to continuous mode, we have studied the influence of variation of tires type and wear and the effects of the final products aging. [ABSTRACT FROM AUTHOR]

Cured and uncured scraps from manufacturing of epoxy based carbon fiber reinforced composites were treated with a pyrolytic process to provide, as solid residue, carbon fibers to be re-used in new composites production. The industrial scraps were pyrolyzed at different temperatures in a 70 kg batch pilot plant and the pyrolysis products (gas, oil, and solid) were fully characterized. The solid residue (carbon fibers covered by a carbonaceous layer) was subjected to a further oxidative step at 500 and 600°C for different residence times to provide fibers devoid of any organic residue that did not volatilize during pyrolysis. The effects of both pyrolysis and oxidative process on the recovered fibers were evaluated by scanning electron microscopy and Raman Spectroscopy. The reinforcement behavior of pyrolyzed and pyrolyzed/oxidized chopped fibers, compared to virgin fibers, was tested in the production of new Chopped Carbon Fiber Reinforced Composites. The optimized double pyrolysis/oxidation process was found to provide fibers whose performance in the composites were comparable to the virgin ones. POLYM. COMPOS., 36:1084-1095, 2015. © 2015 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]