Using ESCA and SIMS in composites manufacturing

The surface analysis techniques of electron spectroscopy for chemical analy sis (ESCA) and secondary ion mass spectroscopy (SIMS) are shown to be indis pensable analytical tools for identifying the chemical composition of bondi ng surfaces used in fiber-reinforced composites manufacturing. Composite pl ys are typically handled in clean rooms. Contaminated tabletop surfaces in a clean room can transfer the contaminant to the plys and result in poor co mposite adhesion. Extruded polyurethane has been used to cover these tablet ops. An example of surface analysis is given by examining the surface conta mination of an old, used tabletop by different methods and comparing that w ith the analysis of a new, clean tabletop. ESCA measurements on used tablet op surfaces found these surfaces to be contaminated with polydimethylsiloxa ne (PDMS) contamination. The presence of PDMS contamination was verified by SIMS analyses. The ESCA and SIMS analysis confirmed polyurethane was the b ase material and SIMS also detected a phthalate component. Energy dispersiv e X-ray microanalysis (EDX) and X-ray fluorescence analysis (XRF) were used to determine bulk elemental chemical composition of the polyurethane used in the tabletop. Fourier transform infrared spectroscopy (FTIR) of the poly urethane and of the collected volatile condensable material (CVCM) extracte d from the total mass loss (TML) experiment conducted on the polyurethane a greed with the EDX data and showed that the bulk material used in the table tops did not contain PDMS. The FTIR of the condensate showed that a phthala te plasticizer was also present in the bulk. EDX detected trace Si at extre mely low concentrations, relative to the bulk. However, the EDX analysis wa s not able to establish the functionality of the Si. Thus, XRF, FTIR and TM L-CVCM were not sensitive to the surface contaminant that ESCA and SIMS wer e able to detect. Finally, ESCA experiments conducted on new tabletop mater ial did not detect any PDMS contamination.