Thermal degradation and pyrolysis kinetic behaviour of glass fibre-reinforced thermoplastic resin by TG-FTIR, Py-GC/MS, linear and nonlinear isoconversional models

Abstract

Recently, global demand for glass fibre-reinforced thermoplastic (GFRP) composites and their applications in the production of wind turbine blades has increased due to their bigger strength, impact resistance, toughness, etc. compared to thermosetting resin. In this work, the thermal degradation and pyrolysis kinetic behaviour of GFRP were studied using TG-FTIR, Py-GC/MS, linear and nonlinear isoconversional models to investigate potential applications in the use of pyrolysis technology in end-of-life GFRP treatment. The experiments were carried out on milled glass fibre/poly(methyl methacrylate)-PMMA composites prepared using the vacuum-assisted resin transfer method and the grinding process. The morphological, ultimate, and proximate properties of the feedstock were observed. The thermal and chemical degeneration of the milled GFRP was studied using TG-FTIR, while the composition of the obtained volatile products was identified using Py-GC/MS. With regard to pyrolysis kinetic behaviour of GFRP, the activation energy (Ea) of whole pyrolysis treatment was determined using Kissinger model, while linear and nonlinear isoconversional models were employed to calculate Ea for each conversion phase. Finally, the kinetic methods of distributed activation energy and the independent parallel reactions were employed to fit TG-DTG experimental data. The results revealed that the GFRP is rich in volatile content (49%), while TG-FTIR analysis showed that C–H, CO, N–O, C–O–C were the main functional groups in the formulated volatile products. Meanwhile, GC/MS measurements showed that methacrylic acid (at 5 °C/min) and 2-Butenoic acid, methyl ester, (Z) (at 10–30 °C/min) were the major compounds in the obtained volatile products with abundance of 92% and 88%, respectively. Meanwhile, the kinetic study showed that Ea was estimated at 200 KJ/mol (Kissinger), 143–184 KJ/mol (linear models), and 153–157 KJ/mol (nonlinear model) with R2 in the range of 92–96.

Keywords

• Glass fibre-reinforced polymers
• Thermoplastic resin
• Pyrolysis treatment
• Poly(methyl methacrylate)-PMMA
• Pyrolysis kinetics