TOF‐SIMS study of injection‐molded polystyrene

Abstract

The purpose of this study was to provide experimental evidence of the separation of the polymer components at different scales during conventional processing. This was achieved by characterizing the surface and the bulk (cross section) of moldings manufactured with a high-flow grade and a low-flow grade of commercial polystyrene by the time-of-flight secondary ion mass spectrometry (TOF-SIMS) analytical technique. Owing to the geometric constraints of the mold used, a weld was also obtained. Different surface spectra were observed for the two molded polystyrenes. The surface of the high-flow grade moldings showed the spectral features of lowmolar polyolefin (parafEn) contaminants, whereas the bulk was dominated by polystyrene. Spectra from both the surface and the bulk of the low-flow grade moldings were characteristic of polystyrene. Mold-filling effects on the surface composition were observed in the flow front region of molded short-shots of the low-flow grade. The spectral changes indicated the abundance, in the surface, of the high end of the molar-mass distribution of the material during the mold filling process. Twodimensional maps of the secondary ions from the low-flow grade also showed an occasional alkali contamination, preferentially along the notch of the weld.

Mass Spectrometry of Synthetic Polymers

“…Surface characterization of polymeric materials using SIMS received considerable attention during this period. Pisciotti et al studied the surface and bulk, through surface analysis of cross sections, of injection-molded high-flow and low-flow grade commercial polystyrene using TOF-SIMS (90). These authors were able to detect differences in the surface spectra for the two polystyrene grades.…”

Image fusion combining SEM and ToF-SIMS images

“…ToF-SIMS imaging could benefit significantly by incorporating image fusion strategies. Two particular areas of interest include biological and polymer sample analysis, [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] where hybrid images will exhibit higher spatial resolution and contain more chemical information. [44,45] In the present study, two test grids with specific spatial features are analyzed by both methods, and images are fused with the Munechika algorithm.…”

“…ToF‐SIMS imaging could benefit significantly by incorporating image fusion strategies. Two particular areas of interest include biological and polymer sample analysis, where hybrid images will exhibit higher spatial resolution and contain more chemical information …”

Spatial Analysis of Time of Flight−Secondary Ion Mass Spectrometric Images by Ordinary Kriging and Inverse Distance Weighted Interpolation Techniques

“…A second area of great activity is the use of multivariate statistics to improve the quality of data and signal-to-noise in TOF-SIMS spectra of organic and polymeric materials. [28][29][30][31][32][33][34][35][36][37][38][39] There have been multiple attempts to improve the clarity of the spectra by implementing different forms of multivariate statistics. In these studies, it was evident that pretreatment steps must be performed on the data before any multivariate statistical analysis could be performed.…”