PARTICLE MORPHOLOGY EFFECTS ON THE PERFORMANCE OF PMMA FILLED WITH ALUMINUM HYDROXIDE IN A VARIETY OF FIRE TESTS

The effect of aluminium hydroxide particle size and shape has been inv estigated on the performance of (polymethyl methacrylate) composites i n a number of flammability tests. As a subsidiary exercise correlation between the tests has been investigated. The work has shown the expec ted effect of particle size on performance, with surface area giving t he best measure of particle size if non-spherical particles are involv ed. While the smallest particles always give the best results the effe ct varies markedly according to the test and is most pronounced in the ISO ignitability test. Some possible explanations for these effects a re proposed but more experiments are needed to choose between them. Co rrelation between the various tests is generally poor and reliance on any one of them for product development would be unwise.