A novel technique for the assessment of dispersion quality in polymeric composites containing high levels of mineral filler or mixtures of different fillers is described. A comprehensive survey of the literature indicates that current methods of assessment using a combination of microscopy and image analysis are reliant on object specific measures which require good contrast between filler particles and the surrounding polymeric matrix. Such methods are inappropriate for the investigation of highly filled systems due to the presence of touching particles and poorly defined feature boundaries. The method described in this report uses characteristic X-rays or backscattered electron (BSE) imaging for the visualisation of filler dispersion patterns. The X-ray technique is especially useful for the discrimination of individual fillers in a multicomponent system. Multifractal analysis of X-ray or BSE images provides a quantitative description of dispersion quality using a numerical indicator derived from the width of the multifractal spectrum. The technique is successfully demonstrated on a series of flame retardant filler-EVA composites containing different amounts of ATH and Mg(OH)2. Linear models were constructed to illustrate the dependence of composite tensile strength and elongation at break on compound formulation and dispersion quality. Optimum material properties were observed for composites displaying good dispersion quality and predicted mechanical properties were compared against experimentally measured data. A positive correlation was found between real test data and predicted values. This technique provides a unique method for the dispersion assessmenot f mineral filled systems and can be performed on any SEM equipped with an EDX spectrometer and access to a PC running image analysis software. It is a useful addition to the current procedures available for the measurement of dispersion quality and should prove invaluable for the study of filled polymer systems.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:298186 |
| Date | January 1999 |
| Creators | Mills, Stephen Leslie |
| Publisher | Manchester Metropolitan University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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