Cold plasma surface modification of conventionally and nonconventionally plasticized poly(vinyl chloride)-based flexible films: Global and specific migration of additives into isooctane

The effect of plasma-induced surface crosslinking of poly(vinyl chloride) ( PVC)-based flexible films was investigated to limit its migration from pack aging into fatty foodstuffs. The global migration was monitored by immersio n into isooctane and the specific migrations of di-2-ethylhexyladipate (DEH A) and epoxidized soybean oil (ESO) were monitored by supercritical fluid c hromatography analysis of the resulting isooctane solution. The plasma indu ced modifications were monitored with respect to the surface energy, weight loss, and surface crosslinking. The global migration from conventionally p lasticized film, whose composition corresponds to an ordinarily used formul ation for the manufacture of PVC wrap films, was controlled by different pl asma treatments and the best results were obtained with Ar plasma. Further decreases in global migration were obtained by treating permanently plastic ized films containing an elastomeric ethylene-based terpolymer (EE in compl ete or partial replacement of DEHA. Before treatment, the replacement of DE HA with EE increased the DEHA and ESO specific migrations. Argon plasma tre atment of permanently plasticized films led to samples that did not exhibit any migration. (C) 2000 John Wiley & Sons, Inc.