Degradation of polyamide 11 in rotational moulding |
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Authors: | Maria Jovita Oliveira Gabriela Botelho |
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Affiliation: | a IPC - Institute for Polymers and Composites, Department of Polymer Engineering, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal b Departamento de Química, Centro de Química, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal |
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Abstract: | The degradation of polyamide 11 (PA 11) was studied in samples rotationally moulded using a range of processing temperatures. The chemical changes occurring in the moulded material were assessed using FTIR, UV-vis spectroscopy, 1H NMR spectroscopy, gas chromatography, rheometry and microscopy. The results showed that the degradation is complex and depends on the location of the material in the moulding. At the internal surface, the degradation is predominantly thermo-oxidative leading to the formation of carbon dioxide, carboxylic acids and conjugated unsaturated oligo-enimines (UV-vis-active chromophores). Away from the internal surface, the dominant process is through the recombination of broken chains and/or post-condensation reactions that increase the molecular weight without the formation of UV-vis-active chromophores. A degradation mechanism is proposed for PA 11 in rotational moulding. |
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Keywords: | Polyamide 11 Degradation Rotational moulding Mechanism UV-vis-active chromophores |
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