pH-Sensitive PP/Clay Nanocomposites for Beverage Smart Packaging

The modification of clay by ion exchange reaction with cationic surfactants plays an important role in the greater interlayer spacing of Na-bentonite. Four types of quaternary alkyl ammonium ions, DO AM, DOEM, DCEM and DTDM, were introduced into the clay in order to investigate the effects of intercalation of the cationic surfactants. The organobentonites were characterized by XRD, FTIR and TGA. From WAXD patterns, DOEM-B exhibited the largest interlayer spacing, promissing the most suitable choice for producing PP/clay nanocomposites. The nanoclay composites incorporating pH indicator were melt compounding through a twin screw extruder using Surlynreg as a reactive compatibilizer. Subsequently, the nanoclay composites were fabricated into the sample sheet for pH-sensitive test.