Next Article in Journal
Effects of Flow Rates and Density Matching on the Integrity of Solid Particles Coated by Water Phase Compound Droplets during the Transport Process
Next Article in Special Issue
Omnidirectional SiO2 AR Coatings
Previous Article in Journal
Comparing Colorfastness to Light of Wood-Staining Fungal Pigments and Commercial Dyes: An Alternative Light Test Method for Color Fastness
Previous Article in Special Issue
Corrosion Inhibition Properties of Waterborne Polyurethane/Cerium Nitrate Coatings on Mild Steel
Article Menu
Issue 5 (May) cover image

Export Article

Open AccessFeature PaperArticle

Stabilized SPEEK Membranes with a High Degree of Sulfonation for Enthalpy Heat Exchangers

Department of Industrial Engineering, University of Rome Tor Vergata, 00133 Roma, Italy
International Associated Laboratory (L.I.A.), Ionomer Materials for Energy, 00133 Roma, Italy
Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123 Perugia, Italy
Department of Engineering, University of Perugia, 06125 Perugia, Italy
Author to whom correspondence should be addressed.
Coatings 2018, 8(5), 190;
Received: 18 April 2018 / Revised: 10 May 2018 / Accepted: 16 May 2018 / Published: 19 May 2018
PDF [6614 KB, uploaded 21 May 2018]


In this investigation, we explored for the first time the use of cross-linked sulfonated poly (ether ether ketone) (SPEEK) membranes in the fabrication of enthalpy heat exchangers. SPEEK is very sensitive to changes in relative humidity, especially when featuring high degrees of sulfonation (DS), though a poor mechanical stability may be observed in the latter case. Cross-linking is crucial in overcoming this issue, and here, we firstly employed the INCA method (ionomer counter-elastic pressure “nc” analysis) to assess the improvements in the mechanical properties. The cross-link was achieved following a simple thermal-assisted process that occurs directly on the performed membranes. After an initial screening, a degree of cross-link = 0.1 was selected as the better compromise between absorption of water vapor and mechanical properties. When implemented in the enthalpy heat exchanger system, these cross-linked SPEEK membranes enabled a high level of sensible heat exchange, as well as a remarkable variation in the mass (water vapor) transfer between the individual air flows. The performances resulted in being better than those for the system based on a benchmark commercially available perfluorinated Nafion membrane. View Full-Text
Keywords: HVAC; SPEEK; cross-linking; INCA method; thin membranes; high DS HVAC; SPEEK; cross-linking; INCA method; thin membranes; high DS

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Narducci, R.; Di Vona, M.L.; Marrocchi, A.; Baldinelli, G. Stabilized SPEEK Membranes with a High Degree of Sulfonation for Enthalpy Heat Exchangers. Coatings 2018, 8, 190.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Coatings EISSN 2079-6412 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top