Characterization of additives at polymer surfaces by ToF‐SIMS

Abstract

Abstract In order to test the possibility of additive concentration quantification based on SIMS data, model samples were prepared. Samples consisted of thin polymer layers deposited by spin coating from solutions containing controlled amounts of selected additives. After identification of the main characteristic additive peaks, the SIMS intensity measured on these samples was compared with the bulk additive concentration. Our results showed that for the Irgafos 168–Hostavin N30 mixtures a linear relationship was found between SIMS intensity ratio and bulk composition. Thus, no synergy effect was detected when these additives are mixed together. However, for Irgafos 168 in copolymer PETi no linearity was observed. The data, based either on relative intensity or on multivariate statistical analysis (principal component analysis), indicated a strong segregation of the additive at the surface, i.e. a possible synergy effect with the polymer matrix. Finally, it appears that the segregation effect depended greatly on the nature of the additive and the polymer because, for the same bulk concentration, copper phthalocyanine in PETi and Irgafos 168 or Irganox 1010 in atactic polypropylene were barely detected. Copyright © 2002 John Wiley & Sons, Ltd.