Reinforcement of Polyvinyl Chloride Using Plasma‐Activated Aramid Fibers and Surface‐Bonded Compatibilizer

ABSTRACT This study investigated the application of a two‐step compatibilization procedure to aramid fiber–polyvinyl chloride (PVC) composites. Aramid fibers were subjected to high radio frequency power air plasma treatment and incorporated into the PVC matrix in the presence of polypropylene‐graft‐maleic anhydride (PP‐g‐MA) as a compatibilizer. Plasma treatment substantially increased the nitrogen and oxygen contents of the fiber surface, introduced higher concentrations of functional groups such as amines and carboxylic acids, and significantly enhanced surface roughness. These modifications promoted strong physicochemical interactions between the fibers and the polymer matrix. The resulting composites exhibited substantial improvements in tensile and flexural properties, viscoelastic behavior, and thermal stability, with performance exceeding those previously reported for similar systems. The enhanced compatibility is consistent with covalent bonding between fiber‐bound functional groups and maleic anhydride moieties on the compatibilizer, together with possible interdiffusion and entanglements between polypropylene and PVC chains. Contrary to the previously‐studied thermoplastic polyolefin (TPO) composites, where plasma treatment alone markedly improved composite properties, PVC systems demonstrated significant compatibilization effects only when plasma treatment was coupled with compatibilizer incorporation. Different reinforcement mechanisms using the same fiber treatment procedure highlighted the role of the host polymer in the effectiveness of interfacial coupling. This work presents a distinctive, environmentally benign compatibilization approach for aramid fiber–PVC systems, addressing a long‐standing challenge in thermoplastic composite design. By leveraging surface chemistry modification and targeted interfacial coupling, the method achieves unprecedented property enhancements without resorting to hazardous treatments. The strategy offers a scalable route to high‐performance fiber‐reinforced thermoplastics with broad applications.