First, pieces of sample are placed in a tube with a metal rod and are then loaded into a grinder. The machine then submerges the tube in liquid nitrogen and shakes it back and forth. This causes the rod to pulverize the frozen pieces of sample.
This sample prep technique can be used to produce a powder from most polymer materials. The longer you cryogrind the material, the finer the powder. One important aspect of this technique is that samples don’t “gum up” because they are frozen.
Cryogrinding is often used as a sample prep technique for chromotography analysis. It also creates maximum surface area for extractables/leachables testing.