AVS 46th International Symposium
    Applied Surface Science Division Monday Sessions
       Session AS1-MoA

Paper AS1-MoA5
Characterization of Polymer Additives by Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

Monday, October 25, 1999, 3:20 pm, Room 610

Session: Molecular Mass Spectrometry including Interpretation
Presenter: R. Kersting, TASCON GmbH, Germany
Authors: R. Kersting, TASCON GmbH, Germany
R. Verlaek, DSM Research, The Netherlands
B. Hagenhoff, TASCON GmbH, Germany
A.P. Pijpers, DSM Research, The Netherlands
B.C. Schwede, ION-TOF GmbH, Germany
Correspondent: Click to Email
Polymers used for industrial purposes generally contain various additives to improve the product performance. Substance classes include anti-oxidants, plasticizers and flame retardants. Typical concentrations are in the order of some 100 to 1000 ppm. Although much is known about the bulk composition of the additive containing polymer not many information on the surface composition of real industry polymers is available. Generally, Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) is an ideally suited analytical technique to characterize the surface composition because it offers detailed molecular information with high sensitivity. On the other hand the surface concentration in real world systems can be very small, even below the detection limit of normal TOF-SIMS analysis. Therefore most TOF-SIMS studies of polymer additives have concentrated on pure materials or highly concentrated model systems. Recently, we have started a systematic study on the secondary ion emission behaviour of polymer additives using model systems containing the additives in their normally applied concentrations and embedding them into their normal host polymer. The study aims at the automated identification of additives in real world samples from their TOF-SIMS spectra. Special emphasis is therefore laid on the emission pattern for use in a spectra library and the determination of detection limits. Different primary ion bombardment conditions (monoatomic primary ions: Ar@super +@, Ga@super +@; polyatomic primary ions: SF@sub 5@ @super +@) were used to study the influence of primary ion mass and polyatomicity on the secondary ion emission. We will present our first results obtained on antioxidants. Whereas most substances can be analyzed to satisfaction using primary ions like Ar@super +@ or Ga@super +@, it turned out that in some cases polyatomic primary ions (SF@sub 5@ @super +@) had to be used in order to reach acceptable detection limits.