POS9-0550
PET/PBT/PTMEG Random Compatibilizers for PET/PBT/TPU Ternary Blends
Topic
S9. Polymer Technology for Sustainability
When and Where
Sep 30, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Heesuk KIM
Jinhye BAE
Presenter(s)
Junyong Seo (BK21 FOUR Department of Materials Science and Engineering, Korea University, Seoul, 02841, Republic of Korea)
Co-Author(s)
Abstract
Mechanical recycling of mixed plastic waste is often limited by phase separation, weak interfacial adhesion, and unstable morphology during melt processing. In this study, PET/PBT/poly(tetramethylene ether glycol) copolyesters (PEBTG) were designed as compatibilizers for melt-mixed PET/PBT/TPU ternary blends. The PEBTG series was synthesized through one-pot melt transesterification/polycondensation, yielding random sequences composed of rigid polyester segments and flexible PTMEG-derived soft segments. The PTMEG content was systematically controlled to tune the segmental balance and interfacial affinity toward both polyester-rich and TPU-rich phases. Chemical structures and compositions were confirmed by ¹H NMR and FT-IR spectroscopy, while GPC and TGA results indicated sufficient molar mass and thermal stability for melt compounding. When incorporated into PET/PBT/TPU blends, PEBTG improved phase interaction and suppressed coarse phase separation. SEM and optical image analyses indicated enhanced interfacial adhesion and macroscopic uniformity in the compatibilized blends. DSC and WAXD analyses further showed that PEBTG modified the crystallization behavior of polyester-rich domains while preserving polyester-derived crystalline features without inducing a new crystalline phase. These morphological and crystallization-related changes were reflected in tensile performance. The elongation at break increased from 298 ± 74% for the compatibilizer-free blend to 494 ± 28% for the optimized compatibilized blend, and toughness increased from 65 to 103 MJ m⁻³, while tensile strength remained within a practical range of 29–36 MPa. These results demonstrate that PET/PBT/PTMEG copolyesters can serve as effective compatibilizers for multicomponent plastic blends and provide a scalable melt-processing strategy for high-value mechanical recycling of real-world mixed plastic waste streams.
