High-temperature chemical and microstructural transformations of a nanocomposite organoceramic

This paper describes the microstructural and chemical transformations occurring at high temperatures in polymer/inorganic crystal nanocomposites referred to as organoceramics. The organoceramic investigated consists of alternating layers of poly(vinyl alcohol) (PVA) and the layered double hydroxide [Ca₂Al(OH)₆]⁺[(OH)•3H₂O] ^-, with a structural repeat distance of approximately 18 Å. The nanocomposite was heated to various temperatures up to 1000°C and analyzed using X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and chemical analysis. The layered structure of the organoceramic was found to be stable up to a temperature of 400°C, whereas the pure layered double hydroxide lacking organic material decomposed at 125°C. The high thermal stability of the organoceramic nanocomposite may arise from an extensive and strongly bonded interface between organic and inorganic components. Interestingly, the organoceramic heated to 1000°C transforms into an inorganic solid which has a different phase composition than the layered double hydroxide heated to the same temperature.