PLA-PBAT-PLA tri-block copolymers: Effective compatibilizers for promotion of the mechanical and rheological properties of PLA/PBAT blends

• Published in: Polymer degradation and stability Vol. 147; pp. 41 - 48
• Main Authors: Ding, Yue, Lu, Bo, Wang, Pingli, Wang, Gexia, Ji, Junhui
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.01.2018; Elsevier BV
• Subjects: Block copolymers; carbon; Chemical synthesis; Compatibility; Compatibilizer; Compatibilizers; composite polymers; Copolymers; Elongation; Interfacial interaction; Mechanical properties; Miscibility; Mixtures; NMR; Nuclear magnetic resonance; nuclear magnetic resonance spectroscopy; Particle size; PLA-PBAT-PLA; Rheological properties; Rheology; stable isotopes; Terephthalate; Miscibility; PLA-PBAT-PLA; Compatibilizer; Interfacial interaction
• ISSN: 0141-3910; 1873-2321
• DOI: 10.1016/j.polymdegradstab.2017.11.012

Polylactide-poly(butylene adipate-co-terephthalate)-polylactide tri-block copolymers incorporating PLA blocks (LPB and HPB) with different chain lengths were synthesized as compatibilizers for PLA/PBAT blends. The structure of the tri-block copolymers could be adjusted by varying the feeding ratios of the monomer and macro-initiator, and the polymers were characterized by 1H NMR, 13C NMR, GPC, and DSC measurements. Compared to the short chains of the PLA blocks (LPB) in the copolymers, HPB was a more effective compatibilizer for two immiscible blends because the long chains achieve enhanced interpenetration of the relevant homopolymers. The elongation between the blocks of the PLA/PBAT blends with 5% HPB compatibilizer was seven times more than that of the pristine blends. The addition of compatibilizer reduced the particle size of the dispersed phase from 1.5 μm to 0.5 μm and improved the miscibility of PLA and PBAT, as confirmed by the thermal, morphological, and rheological properties. The experimental results established that tri-block copolymers improved the interfacial interaction and the miscibility between PLA and PBAT. •Two types of PLA-PBAT-PLA tri-block copolymers were synthesized with definite structure.•The elongation of the blend with 5% HPB compatibilizer was seven times more than that of the pristine blends.•The interfacial phase become indistinct and the size of dispersed phase decrease from 1.5 μm to 0.5 μm.