Effect of 200 days of cyclic weathering and salt spray on the performance of PU coating applied on a composite substrate
The effect of 200 days of cyclic weathering test (CWT) and 1,000 h of salt spray test (SST) on the performance of polyurethane (PU) coating was investigated. A 200 μm coating was applied to a composite and cured before CWT and SST ageing studies. CWT was conducted in ten cycles (each cycle: −40°C fo...
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De Gruyter
2025-05-01
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| Series: | Science and Engineering of Composite Materials |
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| Online Access: | https://doi.org/10.1515/secm-2025-0055 |
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| author | Mushtaq Mohammed Gulipalli Pallavi Adusumalli Ramesh Suresh Kurra Abraham Anu Anna |
| author_facet | Mushtaq Mohammed Gulipalli Pallavi Adusumalli Ramesh Suresh Kurra Abraham Anu Anna |
| author_sort | Mushtaq Mohammed |
| collection | DOAJ |
| description | The effect of 200 days of cyclic weathering test (CWT) and 1,000 h of salt spray test (SST) on the performance of polyurethane (PU) coating was investigated. A 200 μm coating was applied to a composite and cured before CWT and SST ageing studies. CWT was conducted in ten cycles (each cycle: −40°C for 5 days, 70°C for 5 days, 40°C and 90% RH for 5 days, and salt fog for 5 days). Initial water immersion tests concluded that the coated specimens have 37% less water absorption than uncoated specimens. The degradation behaviour of the coating was evaluated by measuring pull-off adhesion strength, critical load from the scratch test, and wear depth from the pin-on-disk test. Similarly, the surface characteristics of the coating were studied by SEM, gloss value, and contact angle. CWT ageing caused a decrease in gloss value (93–78 GU), pigment content (18–8 wt%), contact angle (92–70°), and an increase in wear depth at 20 N of applied load (45–200 µm). Similarly ageing also decreased the pull-off adhesion strength to 6.77 MPa (CWT) and 7.93 MPa (SST). CWT and SST also decreased the thermal stability by 11–13°C, considering 5 wt% loss and tensile strength of the coating from 42 to 29 MPa. The damage to the composite substrate was not significant due to prolonged exposure periods under CWT and SST, though the damage was noted in PU coating, like increased surface roughness and wear depth. |
| format | Article |
| id | doaj-art-b71b25ae21fa4f6e890e1ffdf5a2eb1c |
| institution | Kabale University |
| issn | 2191-0359 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | De Gruyter |
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| series | Science and Engineering of Composite Materials |
| spelling | doaj-art-b71b25ae21fa4f6e890e1ffdf5a2eb1c2025-08-20T03:52:16ZengDe GruyterScience and Engineering of Composite Materials2191-03592025-05-0132118162510.1515/secm-2025-0055Effect of 200 days of cyclic weathering and salt spray on the performance of PU coating applied on a composite substrateMushtaq Mohammed0Gulipalli Pallavi1Adusumalli Ramesh2Suresh Kurra3Abraham Anu Anna4Department of Chemical Engineering, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, IndiaDepartment of Chemical Engineering, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, IndiaDepartment of Chemical Engineering, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, IndiaDepartment of Mechanical Engineering, Birla Institute of Technology and Science Pilani, Hyderabad Campus, Hyderabad, Telangana, 500078, IndiaAdvanced Systems Laboratory (ASL), DRDO, Hyderabad, Telangana, 500058, IndiaThe effect of 200 days of cyclic weathering test (CWT) and 1,000 h of salt spray test (SST) on the performance of polyurethane (PU) coating was investigated. A 200 μm coating was applied to a composite and cured before CWT and SST ageing studies. CWT was conducted in ten cycles (each cycle: −40°C for 5 days, 70°C for 5 days, 40°C and 90% RH for 5 days, and salt fog for 5 days). Initial water immersion tests concluded that the coated specimens have 37% less water absorption than uncoated specimens. The degradation behaviour of the coating was evaluated by measuring pull-off adhesion strength, critical load from the scratch test, and wear depth from the pin-on-disk test. Similarly, the surface characteristics of the coating were studied by SEM, gloss value, and contact angle. CWT ageing caused a decrease in gloss value (93–78 GU), pigment content (18–8 wt%), contact angle (92–70°), and an increase in wear depth at 20 N of applied load (45–200 µm). Similarly ageing also decreased the pull-off adhesion strength to 6.77 MPa (CWT) and 7.93 MPa (SST). CWT and SST also decreased the thermal stability by 11–13°C, considering 5 wt% loss and tensile strength of the coating from 42 to 29 MPa. The damage to the composite substrate was not significant due to prolonged exposure periods under CWT and SST, though the damage was noted in PU coating, like increased surface roughness and wear depth.https://doi.org/10.1515/secm-2025-0055compositepolyurethane coatingcyclic weathering testsalt spray testcharacterizationwater immersion |
| spellingShingle | Mushtaq Mohammed Gulipalli Pallavi Adusumalli Ramesh Suresh Kurra Abraham Anu Anna Effect of 200 days of cyclic weathering and salt spray on the performance of PU coating applied on a composite substrate Science and Engineering of Composite Materials composite polyurethane coating cyclic weathering test salt spray test characterization water immersion |
| title | Effect of 200 days of cyclic weathering and salt spray on the performance of PU coating applied on a composite substrate |
| title_full | Effect of 200 days of cyclic weathering and salt spray on the performance of PU coating applied on a composite substrate |
| title_fullStr | Effect of 200 days of cyclic weathering and salt spray on the performance of PU coating applied on a composite substrate |
| title_full_unstemmed | Effect of 200 days of cyclic weathering and salt spray on the performance of PU coating applied on a composite substrate |
| title_short | Effect of 200 days of cyclic weathering and salt spray on the performance of PU coating applied on a composite substrate |
| title_sort | effect of 200 days of cyclic weathering and salt spray on the performance of pu coating applied on a composite substrate |
| topic | composite polyurethane coating cyclic weathering test salt spray test characterization water immersion |
| url | https://doi.org/10.1515/secm-2025-0055 |
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