Polymer mediated growth and morphology in MNA/PMMA guest/host microdispersed composites

The structure and morphology in the meta-nitroaniline (MNA) dispersed poly( methyl methacrylate) (PMMA) guest/host system was investigated with respect to composition and different techniques of crystallization. Large changes in the intensities of various X-ray diffraction peaks were observed for bot h solution grown (SC) and melt crystallized (MC) MNA/PMMA composite films. However, in the former case, the peak corresponding to (060) reflection had maximum intensity, while in the latter, the peak corresponding to (112) re flection was most prominent. At low concentrations, the films appeared to b e amorphous and transparent, but electron diffraction studies revealed smal l ordered domains. Both solution and melt grown MNA/PMMA films contained tw o types of crystallites having different structures: one having the origina l orthorhombic structure (a = 6.51 Angstrom, b = 19.35 Angstrom, c = 5.07 A ngstrom) of hulk MNA, while the other crystallized in new monoclinic phase with a = 13.0 Angstrom, b = 19.35 Angstrom, c = 10.15 Angstrom and beta = 6 4 degrees. The presence of the new structure that formed could be due to a formation of complex between PMMA and MNA. This complex formation and new s tructure was further confirmed by differential scanning calorimeter (DSC) a nd infrared analysis (IR). (C) 2001 John Wiley & Sons, Inc.