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Ramie fabrics were first pretreated in alcohol and then plasma treated in helium gas for differenttreatment times of 30seconds, 1 and 3minutes in atmospheric conditions. Surface chemistry ofthe treated fabrics was characterized through FTIR analysis and static contact angle. FTIRanalysis showed that the amount of-CH-groups increased on the treated fabrics, which couldhave been as a result of grafting of alkyl layers on the fiber surface.Contact angle measurementsshowed higher contact angles for the alcohol pretreated fibers when compared to the untreatedfibers and the fibers that were only plasma treated without being alcohol pretreated.
Ramie fabric (RF)-Polypropylene (PP) composite materials were fabricated through heat pressmethod and the effect of surface modification on the mechanical properties of the compositeswas characterized through tensile, shear and flexural tests.The fabricated composites showedimproved mechanical properties when compared to the untreated samples.Shear strength showedprogressive increase with increase in treatment time of up to 11.7MPa.Tensile strength increasedby about 20% in 1minute treated composites when compared to untreated fiber composites andthen decreased after 3minute treatment time.Flexural strength also showed a similar trend as totensile properties, flexural strength increasing after 1 minute treatment time and then decreasingafter 3 minutes treatment time.Water absorption properties in the treated samples also showedimprovement, with decrease in water absorption noted with increase in treatment time when thesamples were soaked in distilled water for a total of 480 minutes.SEM images of fracturedsurfaces showed improved bonding between the fibers and the PP matrix with increasedtreatment time.It was concluded that the alcohol pretreatment prior to plasma treatment improved the mechanical properties of the ramie fabric-polypropylene composites through improved surface properties.