ISSN:
0142-2421
Keywords:
SIMS
;
ToF-SIMS
;
polymer
;
molecular weight effects on intensities
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
Time-of-flight (ToF) SIMS spectra were acquired from a variety of elastomer and thermoplastic molecular weight (MW) standards: polyisoprene (PIP), 1,4-polybutadiene (PBD), polyisobutylene (PIB), polyethylene (PE), polystyrene (PS), polypropylene (PP) and poly(1-butene) (P1-B). These spectra were then examined to determine any correlation between relative ion intensities and MW. In all cases, the relative intensities of protonated monomer (monomer+H) ions were particularly sensitive to MW. These monomer+H relative ion intensities were fairly constant at MWs above 20000, but increased dramatically and contiguously as the MW of the polymer decreased below 20000. For all of the polymers examined, the variation of monomer+H ion intensities with MW could be fit using the general relationship: Relative monomer+H ion intensity=M(MW/1000)E+B, where M is the slope, B is the ion ratio intercept and E is an exponent with values between -0.5 and -0.6. Using this general relationship, ToF-SIMS MW calibration lines were developed for PIP, PBD, PIB, PE, PS, PP and PI-B. These calibration lines could be used to determine the presence and approximate MW of low-MW (≤20000) polymer, but could not distinguish the MWs of high-MW (≥20000) polymers. The technique was applied to the analysis of MWs on PP fibers. Moreover, the MW calibrations were shown to be useful for determining the presence of unknown low-MW waxes and additives on polymeric surfaces. © 1997 by John Wiley & Sons, Ltd.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
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