Fabrication and characterization of biodegradable poly(butylene succinate-co-adipate) nanocomposites with halloysite nanotube and organo-montmorillonite as nanofillers

Biodegradable poly(butylene succinate-co-adipate) (PBSA)-based nanocomposites were successfully prepared. A commercial halloysite nanotube (HNT) and an organo-montmorillonite (denoted as 15A) served as reinforcing fillers. Scanning electron microscopy and transmission electron microscopy results confirmed the nano-scale dispersion of HNT and 15A in the composites. Differential scanning calorimetry results showed that 15A served as nucleating agent for PBSA crystallization, but HNT hardly affected the nucleation of PBSA. Both nanofillers assisted the isothermal crystallization of PBSA, with 15A demonstrating superior efficiency. Melting behavior study suggests that the presence of HNT or 15A hampered the melting-recrystallization process of the originally less stable crystals during heating scans. Thermogravimetric analyses revealed that 15A enhanced the thermal stability of PBSA in air environment, but HNT caused a decline at high loadings. The rigidity of PBSA, including Young's/flexural moduli, evidently increased after the addition of HNT or 15A, with 15A showing higher enhancing efficiency than HNT at similar loadings. The flexural modulus increased up to 94% with 20 wt% in HNT and up to 48% with 5 wt% 15A loading. The rheological property measurements confirmed the achievement of pseudo-network structure at 5 wt% 15A loading, whereas the HNT-included system did not develop a network structure.