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

Abstract

The paper describes the effect of structure on moisture regain and dye uptake of copolyester fibers of poly(ethylene terephthalate) and poly(hexamethylene terephthalate), poly(octamethylene terephthalate), and poly(decamethylene terephthalate). The increase in the methylene groups per repeat unit of copolyesters resulted in an increase in moisture regain and dye uptake. The diffusion coefficient values for dye uptake in copolyester fibers containing decamethylene groups were exceptionally high.Water absorption and dyeability are important fiber properties that depend on the chemical nature and the fine structure of the fiber. 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. Copolymerization is a convenient way for improving the dyeability and moisture regain of PET. Several attempts have been made to add a comonomer as a block or in a random manner [1,3,4, 10] to obtain better properties in polymers. In this paper we report the changes in the dyeability and moisture sorption of PET by the incorporation of poly(alkylene terephthalate) units in the backbone. Six copolyester samples were prepared by melt fusion of high molecular weight PET with oligomeric poly-(hexamethylene terephthalate) (PHT), poly(octamethylene terephthalate) (POT), and poly(decamethylene terephthalate) (PDT). The backbone structure of these copolyesters can be depicted as where m = 6 (FH) or 8 (FO) or 10 (FD). (Figures in parentheses indicate the letter designations for these copolyesters.) The copolyesters were prepared by melt fusion of 0.05 mole fraction of PHT/POT/PDT (samples FHI/ / FO,/FD,) with PET. 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. Relative humidities of 65 ± 2% and 84 ± 2% were maintained using saturated salt solution. The fibers were kept for 48 hours at these humidities and then weighed. The dry weight of the fibers was obtained by placing in a vacuum desiccator over phosphorus pentaoxide for 5 days till a constant weight was ...

Poly(alkylene terephthalate)s: From current developments in synthetic strategies towards applications

“…The highest moisture regain and dye uptake was noticed when PAT(p=10) was included in the copolymer because of the lower Tg which increased the segmental mobility and free volume. [11,181] In 2019, Xu et al proved an enhanced ductility when bio-based 1,10-decanediol was incorporated in PBT via a green polycondensation-coupling ring-opening polymerisation. [182] As eco-friendly and sustainable alternative for packaging, Chebbi et al synthesised a series of biobased copolyesters starting from 1,10-decanediol, isosorbide and dimethylfuran-2,5-dicarboxylate monomers.…”

Kinetics of the polycondensation and copolycondensation of bis(3‐hydroxypropyl) terephthalate and bis(4‐hydroxybutyl) terephthalate

“…Therefore, PTT has not been studied as actively as poly(ethylene terephthalate) (PET) and PBT. One possible use of PTT is the improvement of the mechanical, thermal, and elastic properties of polyesters through copolymerization with both monomeric and oligomeric forms as reactants 11–19…”

Characterization of poly(trimethylene/butylene terephthalate) copolymer prepared by the copolycondensation of bis(3‐hydroxypropyl terephthalate) and bis(4‐hydroxybutyl terephthalate)

“…Misra and Garg10, 11 synthesized PET–PBT block copolymers to increase the crystallization rate of PET. Varma et al12, 13 synthesized a PET–poly(alkylene terephthalate) copolymer to enhance the dyeability and hydrophilicity of PET. Smith et al14 investigated the physical properties of P(ET/TT) and P(ET/BT) copolymers.…”