A reactive compatibilization with the compound containing four epoxy groups for polylactic acid/poly(butylene adipate-co-terephthalate)/thermoplastic starch ternary bio-composites

• Published in: International journal of biological macromolecules Vol. 262; no. Pt 1; p. 129998
• Main Authors: Fang, Yong-Gan, Lin, Jian-Yun, Zhang, You-Cai, Qiu, Qi-Wen, Zeng, Yong, Li, Wen-Xi, Wang, Zhao-Yang
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-03-2024
• Subjects: Adipates; Alkenes; Epoxy compound; Epoxy Resins; Melt reactive extrusion; Phthalic Acids; Poly(butylene adipate-co-terephthalate); Polyesters; Polylactic acid; Starch; Thermoplastic starch; Epoxy compound; Thermoplastic starch; Melt reactive extrusion; Polylactic acid; Poly(butylene adipate-co-terephthalate)
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2024.129998

How to effectively improve the poor interfacial adhesion between polylactic acid/poly(butylene adipate-co-terephthalate) (PLA/PBAT) matrix and thermoplastic starch (TPS) is still a challenge. Therefore, this work aims to introduce a convenient method to enhance the performance of PLA/PBAT/TPS blend by melt reactive extrusion. Here, using 4,4′-methylene-bis(N,N-diglycidyl-aniline) (MBDG) containing four epoxy groups as a reactive compatibilizer, and respectively using 1-methylimidazole (MI) or triethylenediamine (TD) as a catalyzer, serial PLA/PBAT/TPS ternary bio-composites are successfully prepared via melt reactive extrusion. The results showed that, under the catalysis of organic base, especially MI, the epoxy groups of MBDG can effectively react with hydroxyl and carboxyl groups of PLA/PBAT and hydroxyl groups in TPS to form chain-expanded and cross-linked structures. The tensile strength of the composites is increased by 20.0 % from 21.1 MPa, and the elongation at break is increased by 182.4 % from 17.6 % owing to the chain extension and the forming of cross-linked structures. The molecular weight, thermal stability, crystallinity, and surface hydrophobicity of the materials are gradually improved with the increase of MBDG content. The melt fluidity of the composites is also improved due to the enhancement of compatibility. The obtained PLA/PBAT/TPS materials have the potential to be green plastic products with good properties.
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•A series of PLA-based ternary bio-composites are prepared by melt reactive extrusion.•The compound MBDG containing four epoxy groups acts as an effective compatibilizer.•The elongation at break can be greatly increased up to 182.4 % as designed reaction.•The biodegradable and low-cost PLA/PBAT/TPS has great potential in green materials.