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Microwave pyrolysis combined with CO2 and steam environment is investigated for its feasibility as an alternative method for waste disposal. The combined use of CO2 and steam under microwave radiation created a synergistic effect in enhancing the thermal cracking of waste material during pyrolysis. The motivation of using CO2 is to replace N2 as carrier gas during pyrolysis as an effort to reduce the production of potent greenhouse gas. In this study, different types of microwave pyrolysis are performed including conventional, CO2 and CO2+steam on waste particleboard. It was found that the utilization of steam and CO2 affect the final pyrolytic products yield and composition. Incorporating CO2 and steam in microwave pyrolysis decreased the yield of char by 33% but increased the yield of bio-oil by 108%. Biochar obtained under CO2 showed well-developed and cleaner pore structure compared to biochar produced under N2. Our results demonstrate that the utilization of CO2 and steam in microwave pyrolysis shows great potential to convert wastes into value-added char and bio-oil with desirable properties.

Structural health monitoring (SHM) plays a significant role to avoid the catastrophic failure of composites during practical applications. This research developed a polyacrylonitrile and flexible barium titanate (PAN/BaTiO3) piezoelectric nanofiber membranes sensor for real-time damage detection in composites. The conversion between mechanical energy and electrical energy of the sensor was verified by an electrochemical system. The introduction of BaTiO3nanoparticles improved the mechanical-to-electrical output of 9.3 V of peak values with 15 wt% loaded piezoelectric nanofiber membranes. In the application test, slight deformation on the piezoelectric nanofiber membranes sensor instantly lighted up the commercial LED bulbs. Moreover, the piezoelectric PAN/BaTiO3sensor still created piezoelectric effect within the composite after curing with carbon fiber, and improved the interlaminated shear strength. The bending and piezoelectric properties of the composite were tested simultaneously. The composite showed good response to electrical signals during the mechanical loading and achieving real-time monitoring of the delamination failure. This sensor showed good potential as a flexible reinforcement in composite materials for SHM applications.