Stone Paper has emerged as an alternative paper-like material of growing interest, consisting predominantly of calcium carbonate (CaCO₃) and a polymeric matrix, commonly high-density polyethylene (HDPE). Unlike conventional cellulose-based paper, the performance of Stone Paper is not governed by a fibrous network but by the interactions between the mineral filler and polymer matrix and by the microstructure developed during processing. Therefore, a comprehensive understanding of the relationships among material composition, calcium carbonate characteristics, surface modification, mixing and extrusion, forming processes, microstructure, and final properties is essential for the scientific evaluation and further development of this material. In this review, studies addressing Stone Paper, together with relevant research on polyethylene/calcium carbonate composites, polymer processing, and materials engineering, are critically examined through an evidence-based framework. The available evidence indicates that increasing calcium carbonate content can enhance stiffness and modulus; however, at high filler loadings, poor dispersion, particle agglomeration, and weak interfacial adhesion may promote stress concentration, interfacial debonding, void formation, and reduced ductility. Particle size and distribution, surface modification of calcium carbonate, and processing conditions are therefore critical parameters governing interfacial interactions and microstructural development. Furthermore, mixing, extrusion, and stretching should not be regarded merely as shaping operations, because polymer-chain orientation, particle rearrangement, and process-induced void formation can substantially influence the mechanical, physical, and functional performance of the final product. The integrated analysis demonstrates that the performance of Stone Paper cannot be adequately described solely by its calcium carbonate content; rather, it results from a complex multiscale interaction among composition, filler characteristics, interfacial behavior, processing history, and microstructure. Accordingly, a materials–processing–microstructure–properties–performance framework is proposed as a useful basis for the scientific analysis and future development of Stone Paper. |
