Polymer-polymer interdiffusion: a brief overview and a study outline on example of coextruded polymer films

A brief overview of the mechanisms of polymer-polymer interdiffusion is presented based on numerous sources. Various existing models describing the diffusion mechanisms are summarized, including the Fick´s law, theories based on the obstruction ef-fects, hydrodynamic models and free volume theories. The strengths and weaknesses of these models are briefly discussed focusing on their applicability for describing polymer melts. The layer boundaries of several combinations of coextruded thermodynamically incompatible plastics, such as PC-PMMA, PC-ABS are visualized using microtome sections and light microscopy. The boundaries were found to be clearly defined, with the interdiffusion layer not visible under light microscopy. A question is raised regarding the impact of the polymer interdiffusion on the adhesion strength between two coextruded polymer layers specifically for polymers with large solubility differences. An outline of the future study and a preliminary experimental approach are briefly described.