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Various methods have been used by the researchers in order to improve the interfacial adhesion of para aramid fibers. In the present research, poly para-phenylene terephthalamide (PPTA) fibers were treated by an innovative method through the utilization of plasma jet in atmospheric pressure using a mixture of oxygen and argon as inlet gases. The effect of the volume ratio of O2/Ar and the treatment time were investigated on the interfacial properties of the fibers via SEM, AFM, ATR-FTIR analyses, and moisture sorption as well as the mechanical tests. SEM images demonstrated significant effect on the surface morphology of the fibers. In addition, ATR-FTIR spectra resulted in the creation of COOH, NH2, and OH groups on the surface of fibers. The increase in the surface functionality led to an improvement in the surface adhesion of the fibers, as observed from the pull-out tests (a maximum of 31% improvement) and moisture sorption tests (a maximum of 54% improvement). According to the results of the tensile and pull-out tests via the design expert software, the optimum condition predicted that using atmospheric pressure plasma jet employing O2/Ar volume ratio of 45.54/54.46% for 20 min results the best adhesion between the fibers and resin.

In this study, indigo-dyed denim fabric was decolorized by washing and printing with separate and simultaneous applications of laccase enzyme, sodium hydrosul te, and cellulase enzyme. In this regard, the surface re ectance and color coordinates of the discolored fabrics were analyzed, and SEM photographs of the treated fabrics were prepared to analyze their surfaces. Finally, the effects of the discoloration process and materials on various parameters of the treated samples were investigated, including moisture content, creaserecovery angle, air permeability, and abrasion resistance. The color experiments showed that the discoloration mechanism with the combined use of laccase enzyme, sodium hydrosul te, and cellulose enzyme had a signi cant effect on the improvement of the lightness (L*) of the samples, as the lightness of the treated samples was improved by 101.18 percent and 55.79 percent in both printing and washing, respectively. Furthermore, examination of specimen color coordinates revealed that the hue of the treated samples was changed to blue and green, and the purity of color (C*) was improved. The increased moisture content and air permeability of the treated specimens suggested that the comfort of the jeans clothing provided by these treatment methods had improved. As a result, it should be noted that the mediating action of sodium hydrosul te was signi cantly in uential for discoloration of denim with the laccase enzyme.