Constructing Amide and Hydrogen Bonds on Glass Fibers for Antistatic Polypropylene Composites Achieving Simultaneous Low Percolation Threshold and High Strength

ABSTRACT Polypropylene random copolymer (PPR) composites are widely employed across various industries; however, their inherently high surface resistivity severely restricts applications requiring antistatic performance. At present, the high filler loadings needed to achieve effective antistatic behavior often compromise interfacial integrity and mechanical properties. To address this challenge, this study proposes a novel strategy to simultaneously realize a low electrical percolation threshold and high mechanical performance in PPR composites. γ‐Aminopropyltriethoxysilane‐sized long glass fibers (LGFs) were utilized as reinforcements, while ionic lithium bis(trifluoromethanesulfonyl)imide (Li‐TFSI) was introduced as an antistatic agent and maleic anhydride‐grafted polypropylene (MPPR) as a compatibilizer, enabling the construction of conductive networks and the optimization of the fiber–matrix interface. The results reveal that Li‐TFSI exhibits a pronounced heterogeneous nucleation effect. However, when its content is below the electrical percolation threshold, coordination bonding between Li ⁺ ions and –NH ₂ groups on the LGF surface suppresses Li‐TFSI from acting as active heterogeneous nucleation sites. As the Li‐TFSI content increases to the percolation threshold of 0.35 wt%, Li ⁺ ions in Li‐TFSI adsorb onto the LGF surface via ion–dipole interactions, leading to the formation of a three‐dimensional conductive network. Meanwhile, the remaining amino groups on the LGF surface react with the carbonyl groups of maleic anhydride to form amide bonds, which still result in a 21.3% enhancement in tensile strength. This study provides theoretical support for the interface‐engineering design of high‐performance antistatic thermoplastic composites.