Polylactide/poly(butylene adipate-co-terephthalate)/rare earth complexes as biodegradable light conversion agricultural films

Rare earth europium(III) complex with alpha-thenoyltrifluoroacetone and triphenylphosphine oxide (Eu (TTA)(3)(TPPO)(2), shortened as EuTT) was synthesized in this paper, then blended with polylactide (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) to prepare the biodegradable agricultural films. Through the optical performance, mechanical properties, and other research, the results showed that the rare earth complex could convert the sun's ultraviolet light to red light when doped polymer. Moreover, the relative intensity ratio of D-5(0)/F-7(2) to D-5(0)/F-7(1) of PLA/PBAT/EuTT film could reach 3.79, which implied that the film had strong fluorescence intensity and high color purity. The highest tensile strength of the film could reach 36.7/25.2 MPa, and the elongation at break was 462.8/483.0% in the machine and in the transverse direction when the added amount of Eu (TTA)(3)(TPPO)(2) was 0.1 wt%. The tensile strength of the film was 33.3/20.1 MPa, and the elongation at break could reach 535.8/413.6% when the added amount of Eu (TTA)(3)(TPPO)(2) was increased up to 0.3 wt%. Gel permeation chromatography showed that the Eu (TTA)(3)(TPPO)(2) could cause depolymerization of polylactide, resulting in a decrease in the molecular weight of PLA. Furthermore, the crystallization ability of PLA was also improved. In this paper, the biodegradable films exhibited excellent ultraviolet light conversion ability and mechanical properties.