Modified abaca fiber prepared by radiation-induced graft polymerization as a reinforcement for unsaturated polyester resin composites

In this study, the preparation and characterization of unsaturated polyester resin (UPR) composites reinforced with abaca fibers modified using radiation-induced graft polymerization are investigated. The aim is to assess the influences of these modified abaca fibers as reinforcement materials on the thermal stability, moisture resistance, and mechanical properties of the composites. The results demonstrate significant enhancements in the tensile and flexural strengths of the prepared composites relative to those reinforced with untreated fibers, yielding minimum increases of 23% in tensile strength and 59% in flexural strength. The most substantial improvement is achieved with abaca fibers modified through the reversible addition-fragmentation chain-transfer-mediated grafting mechanism. In addition, short, grafted chains on abaca fibers produce the greatest enhancement in mechanical strength. The modified composites exhibit improved thermal stability and moisture resistance. These enhancements can be attributed to the improved interfacial adhesion between the modified abaca fibers and the UPR matrix, as confirmed by scanning electron microscope analysis. Overall, these findings highlight the potential of this approach as a surface modification technique for enhancing the applicability of natural fibers in the composite industry. The effect of radiation-induced graft polymerization (RIGP) on abaca fibers was evaluated for composite reinforcement. Using grafted fibers improved composite properties, especially when RIGP was carried out under reversible addition-fragmentation chain transfer (RAFT) mechanism. Controlled chain growth of grafted polymer could be achieved by RAFT-RIGP and this led to the highest improvement in mechanical strength versus pristine fibers and those modified by conventional RIGP. These findings show the capability of RAFT-RIGP to optimize the effectiveness of natural fibers in the composite industry.