Microwave-assisted recycling of carbon fiber-reinforced polymers

The increasing annual demand for carbon fiber-reinforced polymers results in substantial end-of-life and industrial waste. Although landfill disposal is common, alternative waste management methods can provide significant environmental and economic benefits. One of the upcoming and promising methods involves using microwave irradiation to remove the polymer matrix and recover carbon fibers for recycling into new products. In this study, we demonstrate the application of microwave irradiation pyrolyzed for removing the polymer matrix and recovering carbon fibers for recycling into new products, with a particular emphasis on carbon fiber-reinforced polymers produced via three-dimensional printing technology. Microwave irradiation pyrolyzed experiments were conducted on 112 work-pieces with varying carbon fiber volume fractions, subjected to different power levels on two different matrices: onyx and white nylon. Thermogravimetry, X-ray computed tomography, light, and scanning electron microscopy were employed to analyze the decomposition processes and integrity of the recovered carbon fibers. The findings reveal a significant influence of carbon fiber volume fractions on pyrolysis time. Decomposition temperatures were identified to range from 380°C to 500°C, with notable differences between the onyx and white nylon matrices. X-ray computed tomography indicated that polymer decomposition initiates from the interior regions of the samples, culminating in the recovery of carbon fibers through a pyrolysis process of the matrix. Optical and electron microscopy confirmed that the recovered carbon fibers maintained their structural integrity with diameter change, showing no evidence of cracks or damage. These results suggest that carbon fibers recovered through microwave irradiation pyrolyzed can be effectively reused in new products, such as car seats and airplane seat backs. This method offers a sustainable solution for the disposal of carbon fiber-reinforced polymer wast