Need help understanding impact of temperature and content of water/glycol on strength (crush, attrition) of methocel (methyl cellulose) extrudates.
In a given process, methocel is mixed at 150oF at 2wt% with a sand-water mixture (50:50) and 2% glycol. The mixture is then dried to extrudable moisture (20-30%) and extruded into spaghetti-like pills.
Recently the pill strength has been poor, with high level of dusting.
Is the temperature of dispersion too low (150oF)?
Does methocel need to ‘hydrate’ to provide strength?
Does the mixture need residence time and/or low temperature (<100oF) to hydrate? What is the ideal temperature?
Does the methocel loose strength if it dehydrates? Is the process reversible?
At what temperature does methocel dehydration take place?
Does high level of glycol prevent methocel hydration?
Can methocel be extruded with glycol only and still provide strength?
Does presence of certain contaminants (electrolytes, organic acids) prevent hydration?
What is the ideal temperature of extrusion?