2001 journal article
Near-edge X-ray absorption fine structure (NEXAFS) microscopy of a polycarbonate/poly (acrylonitrile/butadiene/styrene) blend
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS, 39(5), 531–535.
author keywords: polycarbonate/acrylonitrile-butadiene-styrene (ABS) blends; near-edge X-ray absorption fine structure (NEXAFS) microscopy; reprocessing
UN Sustainable Development Goal Categories
3. Good Health and Well-being
(Web of Science)
Source: Web Of Science
Added: August 6, 2018
Blends of polycarbonate (PC), poly(styrene/acrylonitrile) (SAN), and polybutadiene (PB), commonly called PC/acrylonitrile–butadiene–styrene (ABS) blends, are complex mixtures. The ABS component consists of free SAN copolymer and SAN grafted onto PB (SAN-g-PB). PC/ABS blends are materials that typically require heavy metal staining to differentiate the separate phases at a high spatial resolution in an electron microscope. Our eventual goal is the characterization of blends of PC and ABS as a function of increasing thermomechanical cycles. Because heavy metal staining is not directly sensitive to potential compositional changes in these polymers, we explored the characterization of PC/ABS blends with a directly sensitive imaging technique: near-edge X-ray absorption fine structure (NEXAFS) microscopy. Here we report NEXAFS spectra of the carbon K shell of PC, SAN, and SAN-gPB, and we evaluate the contrast in a PC/ABS blend across an energy range of 280–295 eV in the presence of TiO2 additives. We unambiguously observed free SAN in the PC matrix. NEXAFS spectroscopy exhibits spectral variations that are sensitive to numerous chemical functionalities and permits the characterization of the composition of organic materials. The information is analogous to what can be obtained in the near edge of core loss features in electron energy loss spectroscopy. During the last few years, the combination of NEXAFS and a high spatial resolution of about 50 nm has been achieved. The resolution has not reached a fundamental limit and is expected to approach 10 nm in the future. NEXAFS microscopy has already been used to image biological systems and examine the morphology and orientation of polymer systems near the K-shell absorption edge of carbon, oxygen, and nitrogen. NEXAFS spectroscopy without spatial resolution has also been successfully used to investigate various polymer surfaces (see refs. 19–26). One advantage of NEXAFS microscopy in imaging polymer systems is that materials of similar electron density and elemental chemistry can be differentiated and complex compositions can be quantified at much higher spatial resolutions than are possible with IR or Raman microscopy. In addition, organic materials can be differentiated directly on the basis of differences in chemical composition rather than through the indirect and aggressive Correspondence to: C. C. Sloop (E-mail: ccsloop@us. ibm.com) Present Address: National Institute of Standards and Technology, Gaithersburg, MD *Present Address: IBM Corporation, Research Triangle Park, NC