Kinetic analysis of the RAFT copolymerization of styrene and maleic anhydride by differential scanning calorimetry
| Autor: | Eduardo Vivaldo-Lima, María de los Ángeles Vargas-Hernández, José Alfredo Tenorio-López, Humberto Vázquez-Torres, Juan José Benvenuta-Tapia |
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| Rok vydání: | 2018 |
| Předmět: |
Analytical chemistry
Maleic anhydride 02 engineering and technology Raft Activation energy 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Isothermal process 0104 chemical sciences Styrene chemistry.chemical_compound Differential scanning calorimetry chemistry Polymerization Copolymer Physical and Theoretical Chemistry 0210 nano-technology Instrumentation |
| Zdroj: | Thermochimica Acta. 667:93-101 |
| ISSN: | 0040-6031 |
| Popis: | A kinetic study of the copolymerization of styrene (S) and maleic anhydride (MA) in the presence of dibenzyl trithiocarbonate (DBTTC) as RAFT agent monitored by differential scanning calorimetry, is presented. The results obtained indicate that the polymerization proceeded in a controlled manner. The average activation energy (E) of the copolymerization obtained by Ozawa and Kissinger methods (62 ± 2 kJ mol−1) showed good agreement with the E value obtained by the isothermal method (67 ± 2 kJ mol−1). These values agree well with the value of 65 kJ mol−1 reported for the nitroxide-mediated copolymerization of S and MA. Calculations using isoconversional methods show that Ea is not constant within the whole conversion range. As the reaction proceeds and higher conversions are reached, Ea decreases to lower values due to diffusion-controlled effects. A first-order reaction model is applied to determine overall kinetic rate constants at different temperatures and different MA molar feed fractions. Polymerization rate increased approximately four orders of magnitude when temperature changed from 90 °C to 110 °C. Polymerization rate is also strongly affected by MA content. It increased by a factor of about three when MA changed from 30% to 50% molar content in the copolymer. |
| Databáze: | OpenAIRE |
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