Cork-Based Composite Materials for Multifunctional Engineering Applications: Processing, Performance and Research Challenges

Cork-based composite materials have emerged as multifunctional, lightweight, and environmentally friendly alternatives to conventional polymer foams in engineering applications requiring energy absorption, thermal insulation, and damage tolerance. This review provides a critical synthesis of advances in cork composites reported between 2015 and 2025, including additive manufacturing approaches, bio-based polymer systems, and impact-resistant structural configurations. Following PRISMA guidelines, 54 peer-reviewed articles were selected from Scopus and Web of Science and analysed using a process-structure-property framework. Cork integration reliably reduces density, provides thermal insulation, and improves damping in fused deposition modelling, stereolithography, and extrusion-based cementitious printing, however, at high cork loadings, printability and interfacial strength suffer. Hybridisation with biodegradable polymers, natural fibres, aerogels, and bio-resins increases acoustic, fire, and moisture-buffering performance in bio-based composite systems, but at the expense of stiffness, durability, and resistance to environmental ageing. Impact-oriented studies indicate that cork-based cores can outperform certain synthetic foams (e.g. EPS or PVC) under low-velocity and repeated impact, particularly in terms of energy absorption and recovery behaviour. Advanced hybrid concepts incorporating shear-thickening fluids and architected layers have been shown to extend performance limits. Despite these advances, major challenges remain, such as a lack of industrial-scale demonstrations, poor understanding of long-term durability under ultraviolet radiation, humidity, and thermal cycling, and a lack of standardised life-cycle assessment frameworks. This review identifies key research priorities necessary to propel cork composites from laboratory-scale development to reliable, high-performance engineering solutions, positioning cork not only as a sustainable substitute but also as an enabler for next-generation multifunctional composite systems in mobility, construction, aerospace, and energy applications.