Structure–property relationship in copolyesters. I. Preparation and characterization of ethylene terephthalate–hexamethylene terephthalate copolymers

摘要

AbstractPoly(ethylene terephthalate)‐containing ethylene and hexamethylene residues in the polymer backbone were prepared by melt condensation reaction of dimethyl terephthalate (DMT) and diffrent quantities of ethylene glycol (EG) and 1,6‐hexane diol (H) in the initial monomer feed. Several polyester samples were prepared by varying the mol of 1,6‐hexane diol with respect to ethylene glycol in the initial monomer feed. These included 0.0 (PET), 2.5 (H1), 5.0 (H2), 7.5 (H3), 10.0 (H4), 12.5 (H5), 15.0 (H6), 17.5 (H7), 20.0 (H8), 50.0 (H9), 80.0 (H10), and 100.0 (H11), respectively. The polymers were characterized by recording IR spectra and intrinsic viscosity measurements. The relative thermal stability of the polymers was evaluated by dynamic thermogravimetry in air. An increase in mol of 1,6‐hexane diol resulted in a decrease in melting points and thermal stability of copolymers. PET and copolyesters were spun to fibers by using the melt‐spinning technique. The fibers were drawn to draw ratios 2,3,4, and 5. In case of copolymes, tensile strength decreases slightly with increasing mol of H whereas elongation increases. The moisture regain and dye uptake in copolyesters was treatly enhanced as compar