Effect of an alkalized-modified halloysite on PLA crystallization, morphology, mechanical, and thermal properties of PLA/halloysite nanocomposites

Poly(lactic acid) (PLA)/alkalized halloysite nanotube (HNTa) nanocomposites were prepared by melt mixing. The morphology, crystallization behavior, mechanical properties, and thermal stability of the nanocomposites were investigated in comparison with those of the pristine PLA. HNTa can nucleate PLA, leading to a lower recrystallization temperature and higher crystallinity. Infrared spectra revealed that the hydroxyl groups of the PLA interacted with the external hydroxyl groups of HNTa nanofillers via hydrogen bonding. The thermal stability of the nanocomposites was improved with the addition of HNTa. The PLA/HNTa nanocomposites exhibited higher modulus and tensile strength than those of the PLA composites containing unmodified halloysite nanotubes (HNTs). The improvement in properties was probably due to a better dispersion of the HNTa in the PLA matrix compared to that of the unmodified HNTs. Therefore, the facile alkali treatment of HNTs offers a low cost nanofiller for the preparation of PLA based nanocomposites with high tensile modulus and tensile strength. (C) 2016 Wiley Periodicals, Inc.