Effect of a compatibilizer on the morphology and properties of polypropylene/polyethylentherephthalate spun fibers

Fibers spun by melt spinning of binary and ternary polypropylene/ polyethylenetherephthalate blends have been produced and characterized in order to investigate the effect of a compatibilizer on their morphology and mechanical properties. The compatibilizer was a maleic anhydride-functionalized rubber copolymer. The effect of the compatibilizer was well evident in the isotropic state, as the morphology became very fine, the size of the dispersed particles was very small, and the adhesion was better. The effect of the compatibilizer on the mechanical properties is very relevant, especially in the elongation at break. On the contrary, no relevant effect was observed in the anisotropic oriented fibers. Although the average diameter of the microfibrils of the dispersed phase of the compatibilized blend generated during the hot drawing was much smaller than that of the microfibrils of the same particles of the uncompatibilized blend, the mechanical properties were almost the same. This behavior has been attributed to the length of the smaller microfibrils of the ternary blends, which was lower that of the microfibrils of the binary blend. This has been explained in terms of reduced initial droplet size, and therefore of lesser possibility of stretching the droplets to very long fibrils in these samples.