Influence of Molecular Structure and Packing on Sorption and Transport Properties of Dichloromethane in Polyetherimides |
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| Authors: | F Galvani A Ruvolo‐Filho |
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| Institution: | 1. Universidade Federal de S?o Carlos, Graduate Program in Materials Science and Engineering , S?o Carlos, Brazil;2. Universidade Federal de S?o Carlos, Graduate Program in Materials Science and Engineering , S?o Carlos, Brazil;3. Universidade Federal de S?o Carlos, Chemistry Department , S?o Carlos, Brazil |
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| Abstract: | The effects of thermal history on dichloromethane vapor sorption and transport properties of polyetherimides were studied. Films were prepared by solution casting at room temperature and heat treated for 24 h at different temperatures below the corresponding glass transition temperature of each material. Changes of the transport properties due to heat treatment were observed and are correlated to changes in density, free volume, and thermal transitions. Deviation from Fick's and Henry's laws was observed for all the samples studied. Without heat treatment and at low activities of the penetrant, the materials studied show sorption kinetics similar to the Fickian behavior. On the other hand, sorption measurements tests for the heat‐treated films at high activities of dichloromethane show kinetics similar to Case II diffusion. Equilibrium sorption data obtained at different penetrant concentrations show deviation from Henry's law behavior depending on the thermal history of the sample. |
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| Keywords: | polyetherimide free volume density heat treatment sorption transport properties |
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