Physical characteristics and morphologies of PTT/m-iPP bi-component filaments of the island-in-sea type

The work discusses preparation, structure and selected properties of two special filaments based on poly(trimethylene terephthalate) (PTT) and metallocene isotactic polypropylene (m-iPP) bi-component filaments of the island-in-sea type. PTT microfilaments are formed by removing m-iPP from PTT (island)/m-iPP (sea) conjugated filaments. m-iPP exhaust dyeable filaments are produced from m-iPP (island)/PTT (sea) conjugated filaments. This study thoroughly investigates the physical characteristics and morphologies of PTT/m-iPP bi-component filaments of the island-in-sea type. The dye exhaustions of the fabrics made of PTT series filaments are compared. Experimental DSC results indicated that PTT and m-iPP crystallites formed an immiscible system. The tenacity of the PTT/m-iPP (and m-iPP/PTT) conjugated filaments initially declined and then increased as the proportion of m-iPP (and PTT) increased. Clearly, the 50/50 weight ratio PTT/m-iPP had the lowest tenacity. The experimental crystallinities revealed that PTT and m-iPP crystallites easily formed individual domains, indicating that PTT and m-iPP together constituted an immiscible system. On the morphology, the blends were had a dispersed phase structure. PTT and m-iPP polymers were immiscible. In this investigation, PTT microfilaments were produced and a large size from 2.3 to 2.6 mu m in diameter was clearly observed. m-iPP exhaust dyeable filaments were also prepared. The dye exhaustions of various fabrics followed the order, m-iPP exhaust dyeable filaments, conventional PTT filaments, PTT microfilaments respectively.