Fraunhofer-Gesellschaft

Publica

Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Superabsorbent polymer additives for repeated barrier restoration of damaged powder coatings under wet-dry cycles

A proof-of-concept
 
: Saini, Vimal; Tapavicza, Max von; Eloo, Christina; Braesch, Katrin; Wack, Holger; Nellesen, Anke; Schmidt, Annette M.; García, Santiago J.

:

Progress in organic coatings 122 (2018), S.129-137
ISSN: 0300-9440
ISSN: 0033-0655
European Commission EC
FP7-PEOPLE; 290308; SHEMAT
Training Network for Self-Healing Materials: from Concepts to Market
Englisch
Zeitschriftenaufsatz
Fraunhofer UMSICHT Oberhausen ()
self-healing; powder coating; superabsorbent polymer; corrosion inhibition; electrochemical impedance spectroscopy

Abstract
Superabsorbent polymers (SAPs) are well known for their ability to absorb and hold high water amounts accompanied by a high volume expansion. In this work we show the benefits of this underlying property of SAPs to induce underwater crack closure with subsequent barrier restoration in damaged protective coatings. For the proof of concept, three layer epoxy-polyester (EP) powder coating systems were developed and applied on carbon steel. In these systems the middle EP layer (also called functional layer) contained crosslinked acrylamide/acrylic acid copolymer SAPs in different amounts ranging from 0 to 40 wt%. The capability of the SAPs to close damages and extend barrier and corrosion protection was evaluated by electrochemical impedance spectroscopy (EIS), NaCl aqueous solution immersion test and optical microscopy. It was found that coatings loaded with a 20 wt% SAP led to the best overall corrosion protection for the studied systems. In order to proof the potential use of this extrinsic healing concept for multiple healing events wet-dry cycles on scratched systems were performed and the corrosion performance was followed by EIS. Although not yet optimal, the results show the potential of the concept for multiple healing events under wet-dry conditions.

: http://publica.fraunhofer.de/dokumente/N-497550.html