Kinetic examination of the mechanical transition of polymethyl methacrylate films prepared from aqueous dispersions
| Autor: | JM Newton, S.V. Lafferty, Fridrun Podczeck |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Phase transition
Range (particle radiation) Materials science Temperature Pharmaceutical Science Aqueous dispersion Activation energy Atmospheric temperature range Kinetic energy Viscoelasticity Excipients Kinetics Polymethacrylic Acids Suspensions Polymer chemistry Polymethyl Methacrylate Stress Mechanical Composite material Thermal analysis Algorithms |
| Zdroj: | International journal of pharmaceutics. 239(1-2) |
| ISSN: | 0378-5173 |
| Popis: | The activation energy of the phase transition of cast polymethyl methacrylate films produced from an aqueous dispersion (Eudragit NE30D) has been estimated from Dynamic Mechanical Thermal Analysis. The value was found to lie between 170 and 350 kJ mol −1 , the variation arising from the different specimen test geometry and testing conditions. From experiments conducted at a range of frequencies and temperatures it was found possible to utilise the concept of frequency shift to produce a master curve, which could relate viscoelastic properties over the temperature range of 5–55 °C and a frequency range of 0.1 to 50 Hz. |
| Databáze: | OpenAIRE |
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