Study on the poly(lactic acid)/nano MOFs composites: Insights into the MOFs-induced crystallization mechanism and the effects of MOFs on the properties of the composites

- The isothermal crystallization kinetics of PLA/MOFs were studied.
- The MOFs-induced crystallization mechanism was discussed.
- The effects of MOFs on the properties of PLA were investigated systematically.
- The mechanical properties and Tg of the composite are significantly increased.

This work aims to develop the poly(lactic acid) (PLA) composites with fast crystallization rate and improved mechanical properties utilizing some unique properties of metal-organic frameworks (MOFs). The MOFs comprised of Zn-O-Zn dinuclear units and multidentate pyridine-2, 5-dicarboxylate linkers were synthesized. SEM and AFM were used to study the distribution of MOFs in PLA matrix and the results indicated MOFs dispersed well in PLA matrix. The significant impacts of MOFs on the crystallization of PLA were observed by DSC and POM. The tensile strength, storage modulus and Tg were improved owing to the reinforcement of MOFs crystals in the PLA/MOFs composites. The tensile strength, storage modulus at 40 °C and Tg of the PLA/MOFs composites with 1 wt% MOFs are increased to 56 MPa, 3425 MPa and 77.9 °C compared with 49 MPa, 1507 MPa and 66.2 °C for neat PLA, respectively.