| Ramie fabrics were first pretreated in alcohol and then plasma treated in helium gas for different treatment times of30seconds,1and3minutes in atmospheric conditions. Surface chemistry of the treated fabrics was characterized through FTIR analysis and static contact angle. FTIR analysis showed that the amount of-CH-groups increased on the treated fabrics, which could have been as a result of grafting of alkyl layers on the fiber surface. Contact angle measurements showed higher contact angles for the alcohol pretreated fibers when compared to the untreated fibers and the fibers that were only plasma treated without being alcohol pretreated.Ramie fabric (RF)-Polypropylene (PP) composite materials were fabricated through heat press method and the effect of surface modification on the mechanical properties of the composites was characterized through tensile, shear and flexural tests. The fabricated composites showed improved mechanical properties when compared to the untreated samples. Shear strength showed progressive increase with increase in treatment time of up to11.7MPa. Tensile strength increased by about20%in Iminute treated composites when compared to untreated fiber composites and then decreased after3minute treatment time. Flexural strength also showed a similar trend as to tensile properties, flexural strength increasing after I minute treatment time and then decreasing after3minutes treatment time. Water absorption properties in the treated samples also showed improvement, with decrease in water absorption noted with increase in treatment time when the samples were soaked in distilled water for a total of480minutes. SKM images of fractured surfaces showed improved bonding between the fibers and the PP matrix with increased treatment time. It was concluded that the alcohol pretrealment prior to plasma treatment improved the mechanical properties of the ramie fabric-polypropylene composites through improved surface properties. |
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