A study on Dyeing Behavior of Modified PP Fibers Produced as Polyblend Fibers Part 1: The Effects of Fibers Draw Ratio and Disperse Dyes Molecular Weight

In this investigation the dye absorption behavior of modified polypropylene (PP) fibers were studied. The modified PP fibers were produced as polyblend polypropylene/poly(butylene terephthalate) (PP/PBT) fibers with an industrial melt spinning machine. The effects of two very important parameters including; draw ratio of fibers and molecular weight of dispersed dyes were considered on dye absorption of pure and modified PP fibers. The results of differential scanning calorimetric (DSC) analysis showed that increasing the draw ratio resulting in decreasing the dye absorption of both pure and modified PP fibers due to the increasing the total crystallinity of fibers. Also, the dye absorption of as-spun and drawn fiber samples have a significant dependency on molecular weight of the dispersed dyes too. So that the lowest dye absorption decrease between as-spun and drawn pure and modified PP fiber samples were observed in the medium molecular weight of the dispersed dye. Scanning electron micrographs of the PBT dispersed phase of polyblend fiber samples showed that the structural variations (such as crystallinity and amorphous regions) are more effective on dye absorption than the morphological properties. Fastness studies of dyed samples were carried out by washing and light fastness of PP modified fibers. The results showed that the mentioned fastnesses depend on both draw ratio of fibers and molecular weight of dispersed dyes.