In-situ lignin modified corn straw/polyethylene/carbon black composites for electromagnetic shielding and inflaming retarding

Abstract

The functionalization of wood-plastic composites (WPCs) represents a significant demand in the fields of green building and the automotive industry. However, the superior distribution of functional components within the polymer matrix remains a challenging endeavor. In this paper, a novel conductive corn straw/polyethylene/ carbon black composite was constructed through an in-situ lignin regeneration strategy, during which the lignin in corn straw (CS) migrated to the surfaces of fibers and the interfacial compatibility among each component was optimized through the polarity modulating of CS. The in-situ lignin modified CS promoted the uniform distribution of conductive carbon black (CB) in the high-density polyethylene (HDPE) matrix, and resulted in LRCS-HDPE-CB_x composites with superior conductivity (12.94 S/m), mechanical properties (e.g., a tensile strength of ∼29.05 MPa for LRCS-HDPE-CB₃₀), thermal stability, as well as promising EMI shielding effectiveness (∼24.00 dB, 8.2–12.4 GHz) and self-extinguishing capability (a limiting oxygen index of 23.5 %) when compared to unmodified CS-HDPE-CB_x composites. Thus, this work provides a simple and viable method for the fabrication of conductive wood-plastic composites exhibiting a uniform compositional distribution and promising functionality.