Preparation and properties of poly (butylene succinate-co-butylene terephthalate)/poly (L-lactic acid) composite films reinforced with coal gangue as a functional filler

Poly (butylene succinate- co -butylene terephthalate)/poly (L-lactic acid) (PBST/PLLA) composite films based on industrially compostable polyester matrices have attracted increasing attention owing to their favorable mechanical properties and packaging potential. In this work, PBST/PLLA was used as the polymer matrix, and an epoxy chain extender was introduced to improve the compatibility between the two phases. Surface-modified coal gangue was further incorporated as a functional filler to regulate the properties of the composite films. The results demonstrated that the dispersibility and interfacial adhesion of modified CG (CGKH 1.0 ) in the matrix were significantly improved. Compared with the composite film material containing unmodified CG (CG-9), the tensile strength and elongation at break of the CGKH 1.0 -9 film increased by 16.2% and 29.5%, respectively. Meanwhile, CG incorporation improved the CO 2 barrier and light-shielding performance, while KH550 modification partially reduced the additional water vapor permeability caused by unmodified CG: the water vapor transmission coefficient ( Pwv ) and carbon dioxide transmission coefficient ( Pco 2 ) of the CGKH 1.0 -9 film were lower than those of the pure PBST/PLLA film, and it also exhibited improved resistance under UV irradiation, hygrothermal aging (85 °C/85% RH), and aqueous hydrolytic environments. This work demonstrates that coal gangue can be transformed into a functional filler for PBST/PLLA composite films, providing a feasible strategy for the high-value utilization of coal gangue in polymer composites. Download: Download high-res image (214KB) Download: Download full-size image