Optimizing electric corona treatment for hydroxypropylated starch-based coatings

Johanna Lyytikäinen; Sami-Seppo Ovaska; Ekaterina Soboleva; Ringaudas Rinkunas; Tadeus Lozovski; Robertas Maldzius; Jonas Sidaravicius; Leena-Sisko Johansson; Kaj Backfolk

doi:10.1016/j.carbpol.2018.06.030

Optimizing electric corona treatment for hydroxypropylated starch-based coatings

Carbohydr Polym. 2018 Oct 1:197:359-365. doi: 10.1016/j.carbpol.2018.06.030. Epub 2018 Jun 6.

Authors

Johanna Lyytikäinen¹, Sami-Seppo Ovaska², Ekaterina Soboleva³, Ringaudas Rinkunas⁴, Tadeus Lozovski⁵, Robertas Maldzius⁶, Jonas Sidaravicius⁷, Leena-Sisko Johansson⁸, Kaj Backfolk⁹

Affiliations

¹ Lappeenranta University of Technology, LUT Energy Systems, Packaging Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland. Electronic address: Johanna.Lyytikainen@lut.fi.
² Lappeenranta University of Technology, LUT Energy Systems, Packaging Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland. Electronic address: Sami-Seppo.Ovaska@lut.fi.
³ Lappeenranta University of Technology, Department of Mathematics and Physics, P.O. Box 20, FI-53851 Lappeenranta, Finland. Electronic address: Ekaterina.Soboleva@lut.fi.
⁴ Vilnius University, Physics Faculty, Sauletekio Av. 9-3, LT-10222 Vilnius, Lithuania. Electronic address: Ringaudas.Rinkunas@ff.vu.lt.
⁵ Vilnius University, Physics Faculty, Sauletekio Av. 9-3, LT-10222 Vilnius, Lithuania; University of Bialystok Vilnius Branch, Faculty of Economics and Computer Science in Vilnius, Kalvariju Str. 143, LT-03101 Vilnius, Lithuania. Electronic address: Tadeus.Lozovski@ff.vu.lt.
⁶ Vilnius University, Physics Faculty, Sauletekio Av. 9-3, LT-10222 Vilnius, Lithuania. Electronic address: Robertas.Maldzius@ff.vu.lt.
⁷ Vilnius University, Physics Faculty, Sauletekio Av. 9-3, LT-10222 Vilnius, Lithuania. Electronic address: Jonas.Sidaravicius@ff.vu.lt.
⁸ Aalto University, School of Chemical Technology, Bioproduct Chemistry, P.O. Box 16300, FI-00076 Aalto, Finland. Electronic address: Leena-Sisko.Johansson@aalto.fi.
⁹ Lappeenranta University of Technology, LUT Energy Systems, Packaging Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland. Electronic address: Kaj.Backfolk@lut.fi.

PMID: 30007623
DOI: 10.1016/j.carbpol.2018.06.030

Abstract

The aim of this investigation was to determine the role of negative direct current and alternating current (plasma) corona treatments in modification of bio-based dispersion barrier coatings and the response of replacing fossil-based binder with a thermoplastic bio-based binder (starch). The study emphasizes the importance of understanding and optimizing electric corona discharge in order to obtain high oxidation level without harming the substrate and causing unintentional treatment of the reverse side. The coatings were exposed to different corona treatment conditions using a novel developed sheet-fed laboratory-scale device. Corona-induced topographical, mechanical and surface chemical changes were observed from atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle and surface energy measurements. XPS results indicated further that partial starch decomposition occurred after plasma treatment. Coated surfaces became substantially smoother after both treatments suggesting that nanoparticle migration and re-orientation effects occurred. Additionally, reverse side effects and strike through were also discussed.

Keywords: Corona treatment; Dispersion barrier coating; Hydroxypropylated starch; Reverse-side treatment; Surface energy.