Quantitative Surface Analysis of Ethylene-Propylene Polymers using ToF-SIMS

Abstract

Copolymers of ethylene and propylene (EPs) and blends of these copolymers with polypropylene (PP) are com-monly used in many elastomer and thermoplastic applications. Ethylene–propylene surface and interfaces have a major effect on EP processing and are important in nearly all EP applications. Despite the importance of these surfaces and interfaces, there have been no methods for quantitatively determining the ethylene and propylene concentrations on surfaces (top 10–30 Å) or in microscopic phases. In this work, time-of-flight secondary ion mass spectrometry (ToF-SIMS) calibrations are developed for quantitative surface analysis of EP polymers. The C3H5+/C2H3+ and C4H7+/C2H3+ intensity variations with EP composition are calibrated to provide quantitative (±5 wt.%) ethylene determinations. Moreover, C5H9+/C2H3+ and C8H13+/C2H3+ intensity variations with EP composition and sequence distribution provide quantitative (±5 wt.%) measures of propylene dyads and triads. Both ethylene and sequence distribution calibrations are then modified for micrometer analysis areas. These new capabilities are applied to a case study involving surface migratory polymer on injection-molded sheet and spun-bond fibers. © 1997 by John Wiley & Sons, Ltd.