Investigation of tensile properties and dyeing behavior of various polypropylene/polyamide 6 blends using a mixture experimental design

Polypropylene has many advantages over other polymeric fibers such as high tensile strength, good abrasion resistance, high chemical resistance and very competitive price. However, the use of polypropylene fiber is restricted by the lack of affinity of conventional dyestuffs for this fiber. Many attempts have been made to improve the dyeability of polypropylene by various techniques. It must however, be noted that enhanced dyeability of polypropylene should not adversely impair its other properties, in particular its mechanical properties. To this end, in the present investigation, a mixture experimental design was used in order to attain an optimal region of proportions of three components namely polypropylene (PP), maleated polypropylene (polypropylene grafted with maleic anhydride (MAH-PP) as a compatibilizing agent) and polyamide 6 (PA6); where enhanced dyeability as well as retained mechanical properties would be achieved. Additionally, in order to analyze the morphology of the blends, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used. Finally, in order to evaluate effect of each component on fastness properties of the blends, wash, rub and light fastnesses were determined by the corresponding standard test methods.

► The design provided two predictive models for tensile properties, both with adequate goodness-of-fit.
► These models reveal that the compatiblizer is effective in improving tensile properties.
► The design also provided a predictive model for K/Smax with adequate goodness-of-fit.
► This model reveals that the PA6 is significant in enhancing disperse dye uptake.
► None of the components have a significant effect on fastness properties of the blends.