Molecular dynamics simulation of polylactic acid/ organoclay nanocomposites: Effects of different organic modifiers

A molecular dynamics study was performed to analyze the effects of different organic modifiers (OMs) on the atomic scale structure, binding energies and basal spacing of polylactic acid/organoclay nanocomposites. Each supercell comprising one molecule of polylactic acid (PLA), montmorillonite (MMT) with a cation exchange capacity (CEC) of 102 mmol/100 g organomodified with several quaternary alkylammonium ions (Quats) and two positively charged amino acids(arginine and lysine) was constructed during simulation tasks. According to the results, amino acids exhibit strong affinity to MMT surface and create considerable spacing room which is very important to intercalation procedure. In contrasting, ordinary Quats demonstrate weaker interaction with MMT unless they are carboxylic modified. This work gave an instructive suggestion for PLA nanocomposites preparation.