Synthesis and characterization of biodegradable aliphatic-aromatic nanocomposites fabricated using maleic acid-grafted poly[(butylene adipate)-co-terephthalate] and organically modified layered zinc phenylphosphonate

Abstract

A new series of biodegradable aliphatic–aromatic nanocomposites containing maleic acid-grafted poly[(butylene adipate)-co-terephthalate] (g-PBAT) and organically modified layered zinc phenylphosphonate (m-PPZn) were successfully synthesized through transesterification and polycondensation processes with covalent linkages between the polymeric and inorganic materials. Fourier transform infrared and 13C NMR spectra demonstrate the successful grafting of maleic acid to PBAT. The morphology of g-PBAT/m-PPZn nanocomposites was investigated using wide-angle X-ray diffraction and transmission electron microscopy. Results showed that the stacking layers of m-PPZn were distributed and intercalated into the g-PBAT polymer matrix. The incorporation of m-PPZn into the g-PBAT matrix significantly enhanced the storage modulus at −70 °C as compared to that of neat g-PBAT. A reduction in thermal stability was observed for all g-PBAT/m-PPZn systems, which is probably due to the lower thermal stability of m-PPZn. The biodegradation of neat g-PBAT copolymers and g-PBAT/m-PPZn nanocomposites was investigated using lipase from Pseudomonas sp. The degradation rates of neat g-PBAT copolymers decrease in the order g-PBAT-80 > g-PBAT-50 > g-PBAT-20. The faster degradation rate of g-PBAT-80 is a result of the higher content of adipate acid units and the chain flexibility of the polymer backbone. Furthermore, the weight loss increases as the loading of m-PPZn increases, indicating that the presence of m-PPZn improves the degradation of the g-PBAT copolymers. This result might be accounted for by the lower degree of crystallinity for g-PBAT/m-PPZn nanocomposites. © 2019 Society of Chemical Industry