Preparation and properties of calcium sulfate whisker reinforced meta-aramid composite paper

Abstract

Electronic devices’ increasing power density and lightweighting demand drive interest in paper-based composites with excellent mechanical, flame-retardant, and electrical insulation. Meta-aramid (PMIA) paper offers high thermal stability but suffers from limited strength and compactness due to inert fiber surfaces and weak interfacial bonding. Incorporating inorganic fillers helps, and phosphogypsum, a phosphate industry solid waste, can be valorized. Here, calcium sulfate whiskers (CSWs) derived from phosphogypsum were integrated into PMIA paper via wet-forming. Low-cost, high-modulus CSWs served as reinforcement, filling voids, forming whisker–fiber interlocking, and hydrogen bonding enhanced structural integrity and dielectric performance. At 30 wt% CSWs, tensile strength reached 69.38 MPa, elongation at break 5.93%, toughness 2.92 MJ/m3, and characteristic breakdown strength increased by 15.09% over pristine PMIA paper, retaining 94.99% after 200°C aging for 24 h. This provides a cost-effective route for high-performance PMIA insulating composites and solid waste valorization.