Ageing of polyamide 11 used in the manufacture of flexible piping |
| |
| Authors: | Wanderson Romão Eustáquio V R Castro Elói A S Filho Regina C L Guimarães Ana L N Silva Sylvia C S Teixeira Marco‐A de Paoli Geovane L de Sena |
| |
| Affiliation: | 1. Departamento de Química, Laboratório de Materiais Poliméricos, Universidade Federal do Espírito Santo, Av. Fernando Ferrari 514, Goiabeiras 29075‐910, Vitória, Espirito Santo, Brazil;2. PETROBRAS S.A./CENPES, Centro de Pesquisa e Desenvolvimento, Cidade Universitária, Quadra 7, 21949‐900 Rio de Janeiro, Brazil;3. Laboratório de Polímeros e Reciclagem, Instituto de Química, Unicamp, C. Postal 6154, 13083‐970 Campinas, Sao Paulo, Brazil |
| |
| Abstract: | The influence of temperature and pH on the ageing of piping made from polyamide 11 (PA‐11) was studied using water from an oilfield (pH = 5.5) and deionized water (pH = 7.0) with monitoring by corrected inherent viscosity (CIV) measurements. The hydrolytic degradation was more extensive at high temperatures in oilfield water. When the system reaches equilibrium, the pH affects mainly the CIV plateau values. Thermogravimetry, energy‐dispersive X‐ray spectroscopy, differential scanning calorimetry, X‐ray diffraction, and scanning electron microscopy measurements were also used to investigate aspects involved in the ageing PA‐11. The hydrolytic degradation of PA‐11 leads to formation of low molar mass compounds, such as oligomers dispersed in the polymeric matrix. This is a process that occurs preferentially in the amorphous domain of PA‐11, which leads to an increase in the degree of crystallinity and the formation of a new γ‐phase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 |
| |
| Keywords: | ageing degradation polyamides viscosity |
|
|
