Synthesis of Poly(Butylene Adipate-co-Butylene-2,6-Naphthalate) Copolymer and Fibers: Characteristics, Thermal and Mechanical Properties

Abstract

This study aimed to improve the spinnability of poly(butylene adipate) polyester through the addition of naphthalene ring structures. First, poly(butylene adipate-co-buthylene-2,6-naphthalate) (PBABN) copolyesters of different ratios were produced through a one-pot polymerization of 1,4-butanediol, adipic acid, and 2,6-naphthalene dicarboxylate (NDC). All PBABN copolyesters maintained good thermal stabilities. As the naphthalene content was increased from 0 to 100 mol%, the glass transition temperature (T_g) of the PBABN copolyester increased from − 60 to 90 °C while its melting temperature (T_m) increased from 50 to 240 °C. When 30 mol% BN units were added, the elongation at break of the PBABN copolyester exceeded 2000%, indicating that the addition of a specific ratio of NDC could improve the elongation of the copolyester. Additionally, PBABN-50 material showed a higher Young’s modulus of 79 MPa, a yield strength of 19 MPa, and an elongation at break of 800%, which show its applicability to packaging materials, agricultural films, and fibers. Second, PBABN copolyesters with BN units above 50% were chosen for melt-spinning into fibers and were post-drawn with a ratio of 3.0 to enhance the fiber strength. The maximum stress values of the fibers with 50, 70, 90, and 100 mol% NDC were 1.93 ± 0.08, 2.82 ± 0.06, 3.89 ± 0.05, and 5.93 ± 0.12 g den^–1, respectively.

Graphical Abstract