From Poly(p-phenylene terephthalamide) Broken Paper: High-Performance Aramid Nanofibers and Their Application in Electrical Insulating Nanomaterials with Enhanced Properties

Poly(p-phenylene terephthalamide) (PPTA) paper serves as a promising matrix candidate that exhibits reduced overall weight and possesses exceptional inherent dielectric strength, thermal durability, and excellent mechanical property and processing flexibility. However, PPTA broken paper in mill is regarded as the solid waste and is landfilled eventually, resulting in severe environmental pollution and waste of resources. In this work, for the first time, an efficient and high value-added approach is proposed for the recovery of aramid nanofibers (ANFs) from PPTA broken papers by controlled deprotonation in KOH/dimethylsulfoxide (DMSO) system. A stable and uniform ANF/water dispersion and the insulating ANF films were successfully obtained. In an effort to explore those possibilities, the effect of ultrosonicon on the compact structure of PPTA broken paper was first investigated. Then the formation process, micromorphology, thermostability, crystalline structure and formation mechanism of ANFs, and the key performances of the ANF films were subsequently investigated and evaluated. The resultant insulating ANF films display higher mechanical performances and dielectric strength than that of the well-known Nomex insulating paper T410. This paper not only opens the possibility of how to recycle PPTA broken paper in an effective and high value-added strategy but also offers an alternative access to advanced nanocomposites with excellent performances.