Modification of Halloysite Filler with Phosphonium based Deep Eutectic Solvents for PLA/HNTs Composites

Polymer nanocomposites have been extensively investigated over the past two decades, resulting in a wide range of applications because of their excellent performance. Halloysite, a type of naturally occurring aluminosilicate, has attracted increasing interest in polymer nanocomposite applications, especially for the enhancement of mechanical properties owing to its tubular structure. Herein, we report a facile to enhance the surface interaction of HNTs with polylactide or poly (lactic acid) (PLA) and to achieve good dispersion of HNTs across the PLA matrix by treating HNTs with Deep Eutectic Solvent (DES). DES system as a modification agent for HNTs was prepared using benzyl triphenyl phosphonium chloride (BTPC) as a salt, in conjugation with glycerol (Gly) as a hydrogen bond donor. Unmodified and modified HNTs were characterized by Fourier Transform Infrared Spectroscopy (FTIR) which revealed the increase of OH groups on HNTs surface. Polylactic acid/halloysite bionanocomposites were prepared with different HNTs and MHNTs loadings (0, 2.5, 5 and 7.5wt%) using solution casting method. The resultant PLA/HNTs nanocomposites were characterized for their mechanical properties. Tensile strength increased to 62.6MPa with the addition of 5wt% of PLA/MHNTs bionanocomposites which is 29 higher than pure PLA and 15% higher than unmodified (5wt%) PLA/HNTs nanocomposites.