Interpenetrating network formation in agarose–sodium gellan gel composites
| Autor: | Eleonora Amici, Valery Normand, Allan H. Clark, N. B. Johnson |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
chemistry.chemical_classification
Aqueous solution Materials science Polymers and Plastics Organic Chemistry Concentration effect Polymer Microstructure Natural gum chemistry.chemical_compound Differential scanning calorimetry chemistry Materials Chemistry Agarose Interpenetrating polymer network Composite material |
| Zdroj: | Carbohydrate Polymers. 46:383-391 |
| ISSN: | 0144-8617 |
| DOI: | 10.1016/s0144-8617(00)00342-8 |
| Popis: | Aqueous cold-set gels from mixtures of agarose and sodium gellan have been characterised structurally and mechanically using optical and electron microscopy, turbidity measurements, differential scanning calorimetry, mechanical spectroscopy and compression testing. Consistent with expectations for charged–uncharged polymer combinations at low ionic strength there is no liquid–liquid demixing in sols prior to gelation, and although transmission electron microscopy reveals heterogeneities in gel microstructures at the higher polymer concentrations, these are small in extent, and are unlikely to arise from normal segregative demixing. Overall, ‘molecularly’ interpenetrating networks (IPNs) are indicated, in which the gellan and agarose architectures pass through one another on a distance scale comparable to their pore sizes. At concentrations greater than 2% w/w gellan, where gellan is the first gelling species, and when the agarose concentration is greater than 0.5% w/w, the composite modulus falls below that expected for the agarose alone. At 0.5% w/w agarose, on the other hand, modulus contributions from the components are much closer to additive. These findings are reflected in the results of large deformation compression testing where breaking stresses show similar trends. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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