Evaluation of intercalation and interaction in in-situ polymerized PLA-HNT bionanocomposites

We report the in-situ synthesis of poly(lactic acid)–halloysite nanotubes (PLA-HNT) bionanocomposites, with a perspective to improve the interaction between PLA and HNT. Three PLA-HNT bionanocomposites with different HNT weight percentages were synthesized by polycondensation, followed by azeotropic distillation technique. Fourier transform infrared spectroscopy studies indicated the existence of hydrogen bonding between terminal hydroxyl groups of PLA and Si–O–Si groups present in the outer surface of HNT. Wide-angle X-ray diffraction, ²⁹Si- and ²⁷Al-nuclear magnetic resonance spectroscopy analysis confirmed the intercalation of PLA into HNT. Scanning electron microscopy analysis confirmed that there was no significant agglomeration and PLA matrix was found to be embedded with HNT. Transmission electron microscopy analysis also gave ample proof to substantiate the intercalation of PLA chains into HNT. Studies on zeta potential of PLA-HNT bionanocomposites, as compared with PLA, also confirmed the interactions between PLA and HNT. Single melting peak in differential scanning calorimetry analysis indicated the existence of one form of crystalline structure.