Poly(vinyl alcohol) desizing mechanism via atmospheric pressure plasma exposure

Atmospheric plasma desizing of poly(vinyl alcohol) (PVA) films was investigated using PVA films supplied by MonoSol. LLCO. The MonoSol (MS) films were exposed to atmospheric plasma for 0.5 to 5.0 min in thirty-second increments with additional specimens exposed for 8.0 and 10.0 min durations. Plasma treatment included exposure to helium plasma (He), oxygenated-helium plasma (He/O-2), and helium/carbon tetrafluoride (He/CF4) plasma. The treated films were characterized by weight loss, surface ablation, molecular weight, and solubility. Weight loss data suggested a mechanism of continual ablation, which increases with increased exposure time until saturation. Redeposition of ablated species may take place because the treatment is in a closed-geometry and thus the saturation trend slightly changes. Thickness changes/surface ablation is in good correlation with the weight loss trends, which suggests that the ablation mechanism is responsible for surface removal. Gel permeation chromatography showed a progressive reduction in the weight-average molecular weight of the PVA chains with increasing treatment durations. This reduction is attributed to chain-scission caused by plasma exposure. Solubility tests showed an increase in solubility of plasma-exposed films in methanol, with a decrease in swelling. These results correlate well with the chain-scission observed through GPC and weight loss trends. On-line atmospheric pressure plasma desizing of textile materials.