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Sobolčiak P, Abdulgader A, Mrlik M, Popelka A, A. Abdala A, A. Aboukhlewa A, Karkri M, Kiepfer H, Bart HJ, Krupa I. Thermally Conductive Polyethylene/Expanded Graphite Composites as Heat Transfer Surface: Mechanical, Thermo-Physical and Surface Behavior. Polymers (Basel) 2020; 12:polym12122863. [PMID: 33265957 PMCID: PMC7760837 DOI: 10.3390/polym12122863] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 11/16/2022] Open
Abstract
Composites of high-density polyethylene (HDPE) and expanded graphite (EG) are prepared for heat exchangers in multi-effect distillation (MED) desalination. At 50 wt.% EG loading, the thermal conductivity of HDPE was increased by 372%. Moreover, the surface wettability of the HDPE/EG composite was enhanced by corona and RF plasma treatment as demonstrated by the increase in surface free energy from 28.5 mJ/m2 for untreated HDPE/EG to 55.5 and 54.5 mJ/m2 for HDPE/EG treated by corona and RF plasma, respectively. This enhanced surface wettability was retained over a long time with only a 9% and 18% decrease in RF and corona plasma-treated samples' surface energy after two months. The viscoelastic moduli and the complex viscosity profiles indicated that EG content dictates the optimum processing technique. At loading below 30 wt.%, the extrusion process is preferred, while above 30 wt.% loading, injection molding is preferred. The plasma treatment also improved the HDPE/EG composite overall heat transfer coefficient with an overall heat transfer coefficient of the composite reaching about 98% that of stainless steel. Moreover, the plasma-treated composite exhibited superior resistance to crystallization fouling in both CaSO4 solution and artificial seawater compared to untreated composites and stainless-steel surfaces.
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Affiliation(s)
- Patrik Sobolčiak
- Center for Advanced Materials, Qatar University, P.O. Box 2713 Doha, Qatar; (P.S.); (A.A.); (A.P.)
| | - Asma Abdulgader
- Center for Advanced Materials, Qatar University, P.O. Box 2713 Doha, Qatar; (P.S.); (A.A.); (A.P.)
| | - Miroslav Mrlik
- Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Trida T. Bati 5678, 76001 Zlin, Czech Republic;
| | - Anton Popelka
- Center for Advanced Materials, Qatar University, P.O. Box 2713 Doha, Qatar; (P.S.); (A.A.); (A.P.)
| | - Ahmed A. Abdala
- Chemical Engineering Program, Texas A&M University at Qatar, P.O. Box 23874 Doha, Qatar;
| | | | - Mustapha Karkri
- CERTES, Université Paris-Est Créteil Val de Marne, 94000 Paris, France;
| | - Hendrik Kiepfer
- Chair of Separation Science and Technology, P.O. Box 3049 TU Kaiserslautern, 67653 Kaiserslautern, Germany; (H.K.); (H.-J.B.)
| | - Hans-Jörg Bart
- Chair of Separation Science and Technology, P.O. Box 3049 TU Kaiserslautern, 67653 Kaiserslautern, Germany; (H.K.); (H.-J.B.)
| | - Igor Krupa
- Center for Advanced Materials, Qatar University, P.O. Box 2713 Doha, Qatar; (P.S.); (A.A.); (A.P.)
- Correspondence:
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