Propane-1,2,3-triol--hexitol (1/1) → Sorbitol

Abrasivity was measured using a PERSPEX procedure. Such a method entailed the utilization of a brush head brushing a PERSPEX plate in contact with a suspension of the silica gel in a sorbitol/glycerol mixture. A slurry composition was first formed of 2.5 grams of the silica gel (or composite gel), 10.0 grams of glycerol, and 23.0 of a 70% sorbitol/30% water syrup. All components are weighed into a beaker and dispersed for 2 minutes at 1500 rpm using a simple stirrer. A 110 mm×55 mm×3 mm sheet of standard PERSPEX Clear Cast Acrylic sheet grade 000, manufactured by Imperial Chemical Industries Ltd, was used for the test. The test is carried out using a modified Wet Abrasion Scrub Tester Brush. In addition a weight of 400 g is attached to the brush assembly, which weighs 145 g, to force the brush onto the PERSPEX plate. The brush has a multi-tufted, flat trim nylon head with round ended filaments and medium texture. A Galvanometer is calibrated using a 45° Plaspec gloss head detector and a standard (50% gloss) reflecting plate. The Galvanometer reading is adjusted to a value of 50 under these conditions. The reading of the fresh PERSPEX plate is then carried out using the same reflectance arrangement. The fresh piece of PERSPEX was then fitted into a holder. Two cm3 of the dispersed silica, sufficient to lubricate fully the brushing stroke, was placed on the plate and the brush head lowered onto the plate. The machine was switched on and the plate subjected to three hundred strokes of the weighted brush head. The plate was removed from the holder and all the suspension was washed off. It was then dried and re-measured for its gloss value. The abrasion value was the difference between the unabraded value and the value after abrasion.