Effect of fly ash on the in-service performance of bamboo–plastic composites for insulation applications

To assess the feasibility of using bamboo–plastic composites in electrical insulation applications, the effect of fly ash—a type of highly productive coal power solid waste—on the in-service performance of bamboo–plastic composites for insulation (hereafter referred to as bamboo–plastic insulating materials) was investigated. The evaluation was based on four standard criteria for solid insulation materials: water repellency, mechanical properties, electrical properties, and voltage resistance. The results showed that with increasing fly ash content, all four properties initially improved and then declined. The maximum reductions in water absorption and the dielectric loss factor were 20.7% and 35.8%, respectively, while the maximum increases in contact angle, tensile strength, flexural strength, insulation resistance, surface flashover voltage, and breakdown voltage were 25.0%, 21.3%, 14.4%, 36.1%, 35.9%, and 7.5%, respectively. Following the breakdown, the microstructure of the bamboo–plastic insulating materials, irrespective of fly ash content, exhibited continuous conductive channels and irregularly distributed pitting.