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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 35: Activated and Glassy Dynamics of Soft Matter (joint session CPP/DY, organized by CPP)
CPP 35.4: Talk
Wednesday, March 9, 2016, 10:15–10:30, H51
Mechanically induced ageing and compaction of porous polymer membranes — •Ulrich A. Handge — Helmholtz-Zentrum Geesthacht, Institut für Polymerforschung, Max-Planck-Strasse 1, 21502 Geesthacht
The permeability of porous polymer membranes often is reduced by mechanical compaction caused by the applied pressure. This process is strongly determined by the viscoelastic properties of the polymer and its plasticization caused by the feed medium. In this work, the time-dependent compaction of porous polymer membranes under pressure is modelled. We focus on the influence of viscoelastic and diffusion properties of the polymer material on compaction and on the decrease of membrane permeability with time. Different membrane morphologies are discussed. The life-time of a porous polymer membrane is associated with the time at which the glass transition is achieved in a creep experiment. We calculate the maximum life-time of polymer membranes based on compaction. The analysis of our model reveals that the diffusion coefficient, the average retardation time in creep, the magnitude of creep compliance and the time-temperature-pressure shift factor strongly influence the pressure induced compaction of microporous membranes. Generally, a larger tortuosity at constant porosity leads to a lower life-time of the membrane. Buckling of cell struts is the dominant failure mechanism in porous membranes with a very high porosity.