Intercalated nanocomposites comprised of polyethylene oxide (PEO) and MPS3 (M = Mn, Cd) or MoO3 are prepared by the direct heating of the alkali-metal intercalated host with PEG. This process, known as melt intercalation, has previously been applied to polymers with layered silicates. Reaction rates and yields are low below the melting temperature for PEG, but at 125 degrees C a significant or quantitative conversion to the ordered nanocomposite can be achieved in 5-30 h. Intercalated nanocomposite yields an followed by powder X-ray diffraction to provide relative reaction rates at 50, 75, and 125 degrees C for PEO with M-w = 1 x 10(5) and 5 x 10(6).