Mechanisms of atmospheric pressure plasma treatment of BOPP

Sawtell, DAG, Abd-Allah, Z, Bradley, JW, West, GT and Kelly, PJ (2017) Mechanisms of atmospheric pressure plasma treatment of BOPP. Plasma Processes and Polymers, 15 (1). ISSN 1612-8850

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Abstract

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Surface energy increase of polymers with plasma treatment is an industrially significant process. The mechanisms behind this process are little understood, with work addressing the water contact angle decrease with treatment and changes in surface chemistry. Work presented here addresses the mechanism of this surface energy increase, by using crystalline biaxially orientated polypropylene (BOPP) films to identify plasma induced structural changes. Increased crystallinity of the BOPP films were observed by ATR-FTIR spectroscopy, indicating preferential oxidation of amorphous regions of the BOPP films by the plasma. This crystal structure change correlates with XRD peak shifts, implying relaxation of crystal regions into regions previously occupied by amorphous BOPP. The trend in surface energy increases also correlates with the effective increase in crystallinity.