Chlorinated Water Induced Aging of Pipe Grade Polypropylene Random Copolymers
Polypropylene random copolymers (PP-R) are common materials for pressurized hot water pipes. In many pipe systems, potable water is disinfected by chlorine to prevent waterborne diseases. This paper deals with hot chlorinated water induced aging of two PP-R grades with varying morphology. One materi...
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| Format: | Article |
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MDPI AG
2019-06-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/11/6/996 |
| _version_ | 1811264607646384128 |
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| author | Joerg Fischer Paul J. Freudenthaler Reinhold W. Lang Wolfgang Buchberger Susan C. Mantell |
| author_facet | Joerg Fischer Paul J. Freudenthaler Reinhold W. Lang Wolfgang Buchberger Susan C. Mantell |
| author_sort | Joerg Fischer |
| collection | DOAJ |
| description | Polypropylene random copolymers (PP-R) are common materials for pressurized hot water pipes. In many pipe systems, potable water is disinfected by chlorine to prevent waterborne diseases. This paper deals with hot chlorinated water induced aging of two PP-R grades with varying morphology. One material had a conventional monoclinic α crystal form (PP-Rα), whereas the other was explicitly beta-nucleated resulting in a trigonal β crystal form with a fine spherulite structure (PP-Rβ). Micro-sized specimens with a thickness of 100 µm were used for aging experiments at 60 °C in chlorinated water with 5 mg/L free chlorine, and aging indicators were monitored for exposure times of up to 2000 h. On the other hand, superimposed mechanical-environmental tests were carried out by using cracked round bar specimens with a diameter of 14 mm to determine the fatigue crack growth (FCG) resistance of both PP-R grades at 60 °C in non-chlorinated and chlorinated water. PP-Rβ was found to outperform PP-Rα with an about 30% higher time-to-embrittlement value of 2000 h. Furthermore, PP-Rβ exhibited an enhanced FCG resistance in both non-chlorinated and chlorinated water. The effect of chlorine content on the deterioration of the FCG resistances was significantly more pronounced for PP-Rα. |
| first_indexed | 2024-04-12T20:07:24Z |
| format | Article |
| id | doaj.art-de91faff16004672a8ed55d67cf5f8fa |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-04-12T20:07:24Z |
| publishDate | 2019-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-de91faff16004672a8ed55d67cf5f8fa2022-12-22T03:18:22ZengMDPI AGPolymers2073-43602019-06-0111699610.3390/polym11060996polym11060996Chlorinated Water Induced Aging of Pipe Grade Polypropylene Random CopolymersJoerg Fischer0Paul J. Freudenthaler1Reinhold W. Lang2Wolfgang Buchberger3Susan C. Mantell4Johannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, AustriaJohannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, AustriaJohannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, AustriaJohannes Kepler University Linz, Altenberger Strasse 69, 4040 Linz, AustriaDepartment of Mechanical Engineering, University of Minnesota, 111 Church Street SE, Minneapolis, MN 55455, USAPolypropylene random copolymers (PP-R) are common materials for pressurized hot water pipes. In many pipe systems, potable water is disinfected by chlorine to prevent waterborne diseases. This paper deals with hot chlorinated water induced aging of two PP-R grades with varying morphology. One material had a conventional monoclinic α crystal form (PP-Rα), whereas the other was explicitly beta-nucleated resulting in a trigonal β crystal form with a fine spherulite structure (PP-Rβ). Micro-sized specimens with a thickness of 100 µm were used for aging experiments at 60 °C in chlorinated water with 5 mg/L free chlorine, and aging indicators were monitored for exposure times of up to 2000 h. On the other hand, superimposed mechanical-environmental tests were carried out by using cracked round bar specimens with a diameter of 14 mm to determine the fatigue crack growth (FCG) resistance of both PP-R grades at 60 °C in non-chlorinated and chlorinated water. PP-Rβ was found to outperform PP-Rα with an about 30% higher time-to-embrittlement value of 2000 h. Furthermore, PP-Rβ exhibited an enhanced FCG resistance in both non-chlorinated and chlorinated water. The effect of chlorine content on the deterioration of the FCG resistances was significantly more pronounced for PP-Rα.https://www.mdpi.com/2073-4360/11/6/996polypropylenepipe gradeschlorinated wateragingfatigue crack growth resistancesuperimposed mechanical-environmental testing |
| spellingShingle | Joerg Fischer Paul J. Freudenthaler Reinhold W. Lang Wolfgang Buchberger Susan C. Mantell Chlorinated Water Induced Aging of Pipe Grade Polypropylene Random Copolymers Polymers polypropylene pipe grades chlorinated water aging fatigue crack growth resistance superimposed mechanical-environmental testing |
| title | Chlorinated Water Induced Aging of Pipe Grade Polypropylene Random Copolymers |
| title_full | Chlorinated Water Induced Aging of Pipe Grade Polypropylene Random Copolymers |
| title_fullStr | Chlorinated Water Induced Aging of Pipe Grade Polypropylene Random Copolymers |
| title_full_unstemmed | Chlorinated Water Induced Aging of Pipe Grade Polypropylene Random Copolymers |
| title_short | Chlorinated Water Induced Aging of Pipe Grade Polypropylene Random Copolymers |
| title_sort | chlorinated water induced aging of pipe grade polypropylene random copolymers |
| topic | polypropylene pipe grades chlorinated water aging fatigue crack growth resistance superimposed mechanical-environmental testing |
| url | https://www.mdpi.com/2073-4360/11/6/996 |
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