A comprehensive review of mica-filled polymer composites for advanced industrial applications

Mica and its polymorphs are extensively utilized as functional fillers in polymer composites; however, their roles remain dispersed across various polymer matrices and application domains. In response to the increasing demand for materials that are lightweight, thermally stable, flame-retardant, dielectric, and cost-effective, this review offers a matrix-specific synthesis of mica-filled polymer composites within major thermoplastic and thermoset systems. The review critically examines peer-reviewed studies spanning several decades, with a focus on mica type, platelet morphology, surface modification, loading, dispersion, processing route, and interfacial compatibility as determinants of composite performance. The evidence indicates that mica serves functions beyond conventional reinforcement, acting as a stiffness enhancer, barrier former, nucleating agent, flame-retardant synergist, dielectric modifier, thermal stabilizer, and damping/insulation component. Across polymer systems, mica performance is influenced by matrix chemistry and interfacial design. In addition, controlled dispersion and platelet orientation facilitate stress transfer and tortuous transport pathways, whereas excessive loading or poor compatibility often result in embrittlement, reduced ductility, and toughness loss. This review thus advances a structure–processing–interface–property framework for interpreting and designing mica-filled polymer composites. Mica is established as a versatile, matrix-sensitive natural filler whose full potential depends on rational formulation, interface engineering, and sustainability-aware material selection.