Measurement of the strength of steric barriers in non-aqueous polymer dispersions
| Autor: | R. Lambourne, A. Doroszkowski |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Journal of Polymer Science Part C: Polymer Symposia. 34:253-264 |
| ISSN: | 1935-3065 0449-2994 |
| DOI: | 10.1002/polc.5070340123 |
| Popis: | The forces of repulsion generated in the steric barriers of a series of monodisperse spherical polymer particles, varying in diameter, have been measured using a surface balance. The particles were stabilized using a graft copolymer with a poly(methyl methacrylate) backbone and heptane soluble poly(12 hydroxy stearic acid) side chains. It was established that the particles were supported on a water surface and that the stabilizing polymer was in a heptane phase in the plane of compression. From pressure-area measurements, a stabilizing barrier thickness of 130 A (independent of particle size) was found which was in good agreement with the value from viscometry. Compression of the particles at the interface permitted the measurement of the collapse pressure of the steric barrier from which the work done in compressing the barrier was computed. Two theoretical models for the system, one similar to Fischer's treatment of osmotic pressure changes associated with the overlap, or inter-penetration, of the steric barrier and another based upon Ottewill and Walker's treatment of the free energy of dilution of the steric barrier have been evaluated. Both models are in good agreement with the experimental data. |
| Databáze: | OpenAIRE |
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