POS1-0692
Molecular Twisting of Poly(butylene terephthalate) through Spirocyclic Comonomer Design
Topic
S1. Polymer Synthesis
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
JIN YOUNG LEE (Chungnam national university)
Co-Author(s)
Abstract
Poly(butylene terephthalate) (PBT) is a widely used engineering polyester owing to its excellent mechanical properties and rapid crystallization; however, its high molding shrinkage, limited transparency, and relatively low glass transition temperature restrict its broader application, particularly in areas requiring dimensional stability and optical clarity. To address these limitations, structural modification through copolymerization has been explored as an intrinsic approach to tailoring PBT properties.
In this study, spiroglycol (SPG), a bulky, nonplanar diol with a rigid spirocyclic structure, was introduced as a comonomer to tailor the chain architecture of PBT. Poly(butylene-co-spirocyclic terephthalate) (PBST) copolyesters containing up to 30 mol% SPG were synthesized via transesterification and polycondensation. The incorporation of SPG units increased the spacing between adjacent polymer chains and disrupted regular chain packing, thereby reducing crystallinity and altering crystallization behavior.
As a result, PBST exhibited modified thermal transition characteristics and more tunable processing behavior compared with neat PBT. In particular, the reduced crystallinity and disrupted chain packing led to enhanced optical transparency, highlighting the effectiveness of SPG incorporation in improving the optical clarity of PBT-based copolyesters. Despite these structural changes, PBST maintained a Young’s modulus of approximately 2.0 GPa, comparable to that of neat PBT, indicating that PBT-like stiffness was preserved. Furthermore, acid-cleavable acetal linkages in the SPG moiety introduced a chemically responsive feature that may enable controlled degradation under acidic conditions.
In this study, spiroglycol (SPG), a bulky, nonplanar diol with a rigid spirocyclic structure, was introduced as a comonomer to tailor the chain architecture of PBT. Poly(butylene-co-spirocyclic terephthalate) (PBST) copolyesters containing up to 30 mol% SPG were synthesized via transesterification and polycondensation. The incorporation of SPG units increased the spacing between adjacent polymer chains and disrupted regular chain packing, thereby reducing crystallinity and altering crystallization behavior.
As a result, PBST exhibited modified thermal transition characteristics and more tunable processing behavior compared with neat PBT. In particular, the reduced crystallinity and disrupted chain packing led to enhanced optical transparency, highlighting the effectiveness of SPG incorporation in improving the optical clarity of PBT-based copolyesters. Despite these structural changes, PBST maintained a Young’s modulus of approximately 2.0 GPa, comparable to that of neat PBT, indicating that PBT-like stiffness was preserved. Furthermore, acid-cleavable acetal linkages in the SPG moiety introduced a chemically responsive feature that may enable controlled degradation under acidic conditions.
