Berlin 2005 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 30: POSTER: Chemical physics
CPP 30.61: Poster
Tuesday, March 8, 2005, 16:30–18:30, Poster TU D
Sol Molecular Weight Distribution of Ion irradiated Polystyrene — •Ralf Delto and Rüdiger Brenn — Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str.3, 79104 Freiburg
Irradiation of polymers with high energetic ions results in a change of molecular weight distribution and produces gel and sol fractions by breaking of chains and formation of crosslinks.
While the crosslinked chains can form an insoluble network (gel), there remains a soluble part (sol). The distribution of molecular weights in the sol depends on the applied ion dose and can hence be controlled experimentally. We calculate the Mw distributions with statistical methods and with numerical simulations.
Measurements are performed on polystyrene (PS) thin films. We use 1 MeV protons for irradiation. The irradiated sol (dPS) diffuses into a polymer network (PS) while heating above Tg. As the diffusion constant depends on the molecular weight, the different species diffuse unequally fast. Thus the diffusion profiles contain information about the abundance of chains of different degrees of polymerisation in the sol. Diffusion depths profiles for the deuterated component (sol) are determined with 3He nuclear reaction analysis.