The mass transport of methanol mixed with ferric chloride hexahydrate (FeCl3 (.) 6H(2)O) in poly(methyl methacrylate) and poly(methyl methacrylate)/iron carbonate particulate(p) nanocomposites is prepared by chemical vapor crystallization and the resulting materials, which are subjected to characterization to evaluate thermal and optical properties, have boon investigated. Mass transport is all anomalous and endothermic process and satisfies the van't Hoff plot. We have prepared successfully poly(methyl methacrylate)(PMMA) /iron carbonate particulates nanocomposites using CO, gas slowly diffused into saturated solvent mixture-treated poly(methyl methacrylate) for 48 h. After SEM observation, approximately 80 nm iron carbonate particulates were precipitated and evenly distributed in the poly(methyl methacrylate) matrix. In comparison with solvent mixture-treated PMMA, the cut-off wavelength of transmittance in nanocomposites shifts to the shorter wavelength side (red shift). The presence of nanoscale iron carbonate particulates increased the glass transition temperature of the nanocomposites as determined by differential scanning calorimeter, and the glass transition temperature increased with increasing content of nanoscale iron carbonate particulates. The FTIR spectra of solvent mixture-treated poly(methyl methacrylate) and nanocomposites are also studied. (c) 2005 Wiley Periodicals, Inc.