Time dependence of the surface chemistry of the plasma treated polypropylene powder

•Polypropylene (PP) powder was plasma treated in fluidized bed reactor.•Ageing of the treated powder was studied by XPS.•Powder was also characterized by SEM, zeta potential and contact angle measurement.•Wettability significantly increased after only 20 s long plasma treatment.

The polypropylene (PP) powder is used for various purposes. However, its good mechanical properties are accompanied by poor wettability. The PP powder was therefore modified by air plasma in fluidized bed reactor (FBR). Several techniques were employed to characterize the treated samples – XPS for the surface chemistry, electrokinetic analysis for zeta potential determination, contact angle measurement for the wettability characterization and SEM for morphology observations. The wettability was enhanced by the plasma treatment and the contact angle of water decreased from 139° to 83° after the plasma treatment. The XPS showed over 20% of oxygen on the surface after the plasma modification. SEM confirmed that only chemistry is responsible for the wettability improvement. No morphological changes were induced by the plasma. The wettability measurements were done also with polyethylene (PE) powder and some similarities between PP and PE were observed.

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