Specific features of the formation of poly(vinylchloride)-dye composites based on solvent-crazed nanostructured polymer matrices

Abstract

Healing and migration of dye molecules in porous nanostructured amorphous-polymer-dye systems prepared by solvent crazing are studied by the method of spectroscopy in the visible spectral region. The conversion of the above processes is controlled by the temperature in the temperature interval above Tg of the bulk polymer. Both processes proceed simultaneously and are independent. After the removal of AALE from the composite and shrinkage of the polymer sample at room temperature, crazes preserve their fibrillar structure, which can be identified by light scattering at 400–600 nm. The main contribution to healing from the fibrillar material of crazes is provided by the reptational mobility of macromolecules, a conclusion that is confirmed by the power dependence of light scattering of the sample on the duration of its thermal treatment with an exponent of 1/4 as well as by the activation energy of this process, which is ∼400 kJ/mol. The kinetic dependences of the intensity of absorption bands of monomer forms of a dye on annealing time have an exponent of 1/2 and show two linear regions. This behavior can be explained by the migration of dye molecules in their monomer form from their absorbed state on the surface of the fibrillar crazed material first into the volume of fibrils and then into the volume of bulk-polymer regions. All the above phenomena are provided by the unique structure of the solvent-crazed polymer material (alternation of the closely spaced regions containing fibrillar material and bulk-polymer regions).