Assessing supply chain resilience and scale-up economics of Kenaf-PLA biocomposites for China automotive markets

Ensuring resilient supply chains and achieving scalable economics are critical prerequisites for the commercial deployment of kenaf (Hibiscus cannabinus L.) fiber-reinforced polylactic acid (PLA) biocomposites in China's rapidly expanding automotive sector. This study evaluates the supply chain architecture—spanning kenaf cultivation in Jiangxi, Hunan, Guangdong, and Zhejiang provinces, controlled tank-retting, alkali-silane surface modification, and twin-screw extrusion compounding—through an integrated resilience and cost-scaling lens. Two-season field experiments established optimal agronomic conditions (180 kg N ha⁻¹; 450,000 plants ha⁻¹), yielding a maximum dry stem output of 7842 ± 134 kg ha⁻¹ and a bast fiber yield of 2318 ± 47 kg ha⁻¹. Controlled tank-retting (32°C, 21 days) significantly reduced fiber quality variability—a key supply chain resilience indicator—achieving peak tensile strength of 621.4 ± 9.3 MPa. Combined alkali (6% NaOH, 4 h) and silane treatment (1.0 wt% APTES) enhanced interfacial shear strength by 61.2%. Biocomposites at the scale-optimized 30 wt% fiber loading achieved tensile strength of 78.6 ± 2.4 MPa, flexural modulus of 5.84 ± 0.11 GPa, and impact resistance of 42.3 ± 1.8 kJ m⁻², meeting Chinese automotive standards (GB/T 1449–2005; GB/T 1447–2005; GB/T 1843–2008) for non-sun-exposed interior components. Scale-up cost analysis indicates price competitiveness with glass fiber/polypropylene panels at > 50,000 units per annum. Life-cycle assessment demonstrated a 38.2% reduction in global warming potential (2.84 vs. 4.60 kg CO₂-eq kg⁻¹ panel). This work delivers a quantitative, supply-chain-informed roadmap for scaling kenaf-PLA biocomposites within China's dual-carbon policy framework.