Effect of encapsulation with zeolite and coating with TiO2 on the thermal stability of caffeine during melt extrusion of a PET/TiO2@(zeolite/caffeine) nanocomposite

摘要

The practice of encapsulating a functional material in a thermally stable porous material displays great potential in preventing decomposition during high-temperature processing. In this study, caffeine encapsulated in zeolite was coated with TiO2 to withstand high-temperature melt extrusion with poly(ethylene terephthalate) (PET). Two coating processes were trialed: in situ encapsulation and coating where TiO2 precursor was added to zeolite/caffeine solution; and ex situ coating in which pre prepared zeolite/caffeine capsules were added to the TiO2 precursor for coating. The TiO2-coated nanocomposites were melt-extruded with PET at 285 degrees C. Residual amounts of caffeine confirmed the shielding effect of the TiO2 coating during the high-temperature melt extrusion. The in situ TiO2 coating process was more effective than the ex situ process. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.