Catalytic pyrolysis and kinetic study of glass fbre‑reinforced epoxy resin over CNTs, graphene and carbon black particles/ZSM‑5 zeolite hybrid catalysts

Abstract

The recovery of short fbre and epoxy resin from glass fbre-reinforced epoxy resin composites (GFRP) poses a major chal- lenge to the waste recycling sector. These challenges grow when GFRP is mixed with other additives such as carbon nano- tubes (CNTs), graphene (GA), and carbon black particles (CB). However, the complexity in terms of activation energy (Ea) can be decreased through involvement of ZSM-5 zeolite catalyst in the pyrolysis process to convert resin component into chemical and energy products. Within this context, this research aims to study the catalytic pyrolysis of GFRP mixed with three fllers with diferent structures and dimensions (nanofllers “CNTs, GA” and micro-fller “CB”) over zeolite catalyst, where these fllers can be used alongside zeolite particles as hybrid catalysts during the thermal conversion process. The GFRP mixed with diferent fller panels were prepared in the laboratory using a vacuum-assisted resin transfer method, then they were ground to fne particles and mixed with 200 mass% of ZSM-5 catalyst to prepare them for thermochemical experiments using thermogravimetry (TGA) at 5–30 °C min−1. The efect of various hybrids on the formulated pyrolysis vapours was studied using TG-FTIR and GC–Ms measurements. The kinetic Ea of each batch was studied using three linear isoconversional methods and two nonlinear isoconversional methods to investigate their efect on the decomposition mecha- nism. Besides, their thermochemical decomposition curves (TGA-DTG) were numerically simulated using DAEM and IPR models. The FTIR and GC analyses revealed that the hybrid catalyst had enhanced formation of aliphatic compounds and phenol compound in case of nanofllers up to 54% (CNTs) and 57% (GA), hence improving them by 17 and 54%, respec- tively. Meanwhile, the kinetic analysis showed that hybrid catalysts can contribute to a signifcant reduction in Ea up to 158 kJ mol−1 (CNTs), 127 kJ mol−1 (GA), and 124 kJ mol−1 (CB), which means that the decomposition of GFRP, becomes easier and requires less energy. Also, the simulated and experimental results showed big consistency in terms of smaller reac- tion complexity and higher generation of volatile compounds with increasing heating rates and addition of hybrid catalysts.