Nano-biochar reinforced polymer composites: Interfacial engineering, functionalization and high-performance applications

As the environmental impact of petroleum-based plastics and non-renewable reinforcement fillers mounts, sustainable and multifunctional composite materials are emerging as a priority. Among the emerging alternatives, nano-biochar’s inexpensive, carbon-negative, multi-functional and tunable surface chemistry properties are getting considerable attention. This review examines the recent innovations in nano-biochar reinforced polymer composites, focusing on feedstocks, thermochemical conversion technologies, surface functionalization, polymer-nano-biochar interactions and polymer fabrication technologies. Several studies indicates that optimized nano-biochar can improve the tensile strength by 15%–45% and flexural strength by 10%–40%, thermal stability by 20°C70°C, moisture absorption by 15%–40% and EMI-shielding effectiveness of 30–40 dB, depending on the matrix, nano-biochar dosage, particle size and functionalization method. Nano-biochar imparts enhanced mechanical, electrical, thermal, barrier and flame properties that offer multifunctional advantages over conventional fillers and also sequesters CO 2 while circularizing the resource stream. However, numerous challenges like feedstock variability, dispersion, lack of standardization, restricted large-scale processing and insufficient understanding of the degradation mechanism still exist is a drawback that is delaying its commercialization. Further research is needed on AI-enabled materials design, scalable functionalization methods, hybrid nanofiller systems and life cycle optimization for commercialization of high-performance sustainable biochar nanocomposites for usage in automotive, energy storage, biomedical, packaging and electronic applications.