Interaction of powder particles with water vapor at certain temperatures can unexpectedly transform free flowing powders into sticky powders, thereby causing all sorts of highly undesired issues: powder stickiness. Think of sticky powder in spray dryers or sticky product during storage in big bags or hoppers leading to a cake-like product and poor dosing and flow properties.
Prediction of powder stickiness is key in preventing above-mentioned problems, but is not an easy task since every product will act differently towards variation in relative humidity and temperature of the air to which the powder is exposed. The intimate relation between temperature and humidity makes predicting even more difficult. Accordingly, dedicated equipment and expertise is required to study this powder stickiness behavior.
We have two main instrumental techniques available:
- Water vapor adsorption isotherms at different temperatures and relative humidity of 0-95%
- Powder rheometry under real time conditions of temperature and relative humidity
We have recently published a scientific paper on powder stickiness using the above-listed methodologies; a copy of the paper can be requested via this link.