Using Optical Light Microscopy and Scanning Electron Microscopy to Analyse and Quantify Flexible Polyurethane Foam Cell Size

It is suspected that flexible polyurethane foam cell size had an influence on the foam property. Obtaining reliable flexible polyurethane foam cell size measurement can be difficult due to inclusion of region of the foam which is not representative of the bulk material. This research is focus on the method to analyse and quantify the foam cell size of flexible polyurethane foam specimens. Two techniques are combined to analyse foam cell size. Initially Optical Light Microscopy was utilised for preliminary evaluation of the overall foam sample. Next, Scanning Electron Microscope (SEM) is set at 5 kilovolts and beam probe current at 5 pico-amps to allows scanning of uncoated foam samples. Flexible polyurethane foam cell size is determined from SEM micrographs obtained by using ASTM D3576 Standard. The average cell size and its range from nine results obtained were calculated and were found to be from 558 microns to 561 microns. Results from SEM micrographs show very small variation since the flexible polyurethane foam has a uniform foam cell size through-out the foam core and areas of broken cells and distorted cells due to slicing action during sample preparation were avoided during preliminary overall cell size evaluation using Optical Light Microscope. This research has shown that by using Optical Light Microscopy and Scanning Electron Microscopy, flexible foam cell size can be analyse and quantify accurately and reliably by avoiding region of the foam with broken cells and distorted cells due to slicing action during sample preparation.