A useful method to determine whether a treatment will protect hair against breakage is provided by repeated grooming experiments. In this test, the number of broken fibers is recorded as a function of repeated combing/brushing strokes. Any treatment that reduces snags, entanglements and abrasion can help in substantially lowering the number of broken fibers.
Our methodology utilizes a custom-built automated grooming device shown below. It consists of a hollow rotating drum-like assembly where four outer crossbars contain holders for mounting combs or brushes. These outer arms are detachable to allow for different holders to be mounted and experiments to be performed using a variety of combs or brushes. The four combs or brushes are mounted at 90o angles and in one complete drum revolution the tress is combed or brushed four times. Plates are located under each tress to collect fiber fragments, while spacer plates on the rotating drum prevent cross contamination. Experiments are performed in a controlled humidity room