Sustainable biobased composites for advanced applications: recent trends and future opportunities - A critical review

The rising environmental and sustainability consciousness has motivated efforts for configuring biobased composite materials for different end-use applications and as a novel alternative to conventional non-renewable synthetic fibers such as glass and carbon reinforced composites. On the other hand, biocomposite materials are not a problem-free substitute, and they have some drawbacks such as poor moisture resistance (hydrophilicity), fiber/matrix incompatibility, supply logistic issues, low thermal stability, flammability, poor electrical properties, extraction, processing, surface modification, machining, manufacturing and characterization associated challenges, and highly anisotropic properties. In recent times, extensive research has been performed to address the challenges allied with long-term durability, reliability, serviceability, properties and sustainable production (via adopting a circular economy in biocomposites). This article presents a critical review of the recent works allied with different aspects of biocomposites. We initially review the overall characteristic including, the extraction, chemical composition, and physical and mechanical properties of the most popular biopolymers and biofibers (based on natural and synthetic resources) employed for fabricating biocomposites. The approaches and advances in enhancing the properties of biocomposites are also reviewed, including fiber treatment and modification, fiber hybridization, incorporation of fillers, advanced manufacturing techniques, and exploration of new biofiber and polymer resources. Also, the present techniques and the developments employed for the manufacturing of biocomposites are discussed, with an emphasis on additive manufacturing techniques (AM) in order to meet the aspirations of lightweight composites. The opportunities and challenges allied with fused filament fabrication (FFF) AM of biocomposite are also discussed in detail. Finally, the characterization techniques, environmental effects, major applications, and trends and challenges of biocomposites are briefly discussed. This review article provides vital information on advanced bio-based materials and their composites for their prospective usage in different high-performance applications.