Advancing sustainability: circular economy strategies for fibrous polymer composites

• Comparative assessment of mechanical, thermal, and chemical recycling reveals clear trade-offs in fiber recovery and energy demand. • Life cycle evaluation shows recycled HDPE, PET, and carbon fibers outperform virgin materials in cost and environmental impact under policy incentives. • Hybrid recycling with process control achieves ∼90% fiber quality retention while reducing overall processing costs. • AI- and IoT-enabled monitoring improves traceability, process efficiency, and circular-economy performance. Fibrous polymer composites are widely used in aerospace, automotive, and renewable energy due to their lightweight and high-strength properties. Traditional linear production and disposal methods, however, cause resource depletion and environmental impacts. This review critically synthesizes circular economy strategies for fibrous polymer composites, integrating material selection, additive manufacturing, and recycling pathways. Mechanical, thermal, and chemical recycling methods are compared in terms of fiber recovery (60–90%), energy consumption (0.5–5.0 MJ/kg), and economic feasibility, highlighting trade-offs between efficiency and scalability. Agro-based and synthetic fibers are evaluated for their performance and sustainability potential. Implementable strategies such as design-for-disassembly, hybrid recycling, AI-driven material traceability, and policy–industry collaboration are discussed to enhance circularity. By providing a systems-level framework linking composite design, end-of-life management, and industrial application, this review identifies critical research gaps, informs sustainable composite development, and offers policy-relevant guidance to promote environmental and economic benefits. By emphasizing recycling, renewable fibers, and resource-efficient design, this study supports the advancement of cleaner, more sustainable composite materials.