Poly(ethylene Terephthalate)/Poly(alkylene Terephthalate) Copolyester Fibers: Mechanical and Physical Properties

Abstract

Copolyesters were prepared by melt condensation of poly(ethylene terephthalate) (PET) with poly(hexamethylene terephthalate), poly(octamethylene terephthalate), and poly(decamethylene terephthalate). These polymers were characterized by 13C- NMR and intrinsic viscosity measurements. The PET and the copolyesters were spun into fibers using the conventional melt spinning technique. The fibers were drawn to ratios of 3, 4, and 5. Decreases in Tg, Tc, Tm, density, birefringence, crystallinity, and orientation were observed in the copolyester fibers, with an increase in the number of methylene groups in the PET backbone.

The Structure and Properties of Typical Melt-spun Fibres

“…A decrease in Tg, crystallization temperature, and melting temperature was observed [96] in the copolyester fibres PET/poly(alkylene tereph thai ate) with an increase in the nunt)er of methyl ene groups in the polyester backbone.…”

“…The mechanical and physical properties of PET/poly(alkylene terephthalate) copolyester fibres were discussed by Varma et al [257]. A decrease in glasstransition, crystallization, and melting temperature and a decrease in density, birefringence, crystal!inity, and orientation .were observed in copolyester fibres, with an increase in the number of methylene groups in the polyester backbone.…”

Poly(ethylene Terephthalate)/Poly(alkylene Terephthalate) Copolyester Fibers: Sorption and Dyeability

“…The main factors governing , the dyeing behavior of polymers are crystallinity, orientation, and size of crystalline region, as well as the mobility of the polymer chains characterized by the glass transition temperature. Thus the total number of amorphous regions and the accessibility of these regions control the dye uptake and moisture absorption in hydrophobic fibers such as poly(ethylene terephthalate) [2].In our earlier papers, we have reported the changes in the Tg, T & d q u o ; & d q u o ; and fine structure of PET by incorporating a low mole fraction of a comonomer in the backbone [5,6,7,8,9,11 ]. The comonomer unit disturbs the packing of molecular chains, thereby decreasing the crystallinity and orientation and increasing the amorphous regions.…”

“…In our earlier papers, we have reported the changes in the Tg, T & d q u o ; & d q u o ; and fine structure of PET by incorporating a low mole fraction of a comonomer in the backbone [5,6,7,8,9,11 ]. The comonomer unit disturbs the packing of molecular chains, thereby decreasing the crystallinity and orientation and increasing the amorphous regions.…”

“…Samples FH2 and F02 were obtained by melt fusion of 0.07 mole fraction of PHT/ POT with PET, while sample FH3 was prepared by melt fusion of 0.10 mole fraction of PHT with 0.9 mole fraction of PET. The details of preparation and characteristics of these copolyesters and of their spinning into fibers have been reported elsewhere [7]. Experimental ' Moisture regain of 5DR heat set copolyester fibers was measured by the vacuum desiccator method.…”