Flexabrasion: A Method for Evaluating Hair Strength

June 26, 2009 | Contact Author | By: J. Alan Swift, Developmental Toxico-Pathology Group; Surinder P. Chahal and Debra L. Coulson, Croda Colloids Ltd.; and Nicholas I. Challoner, Croda Oleochemicals Ltd.
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Keywords: testing | claim substantiation | hair strength | hair breakage | flexabrasion

Abstract: Both bending and abrasion should be tested—along with extension—when evaluating hair strength, as the authors show in tests of a new active for increasing the strength of bleached hair.

Tensile test methods have been successfully used to demonstrate improvements in the mechnanical properties of hair, however they assess only one aspect of the physical processes of hair fracture that the consumer normally uses to evaluate the strength of hairs on the head. A more realistic test would involve all the elements--fiber bending (flexure), abrasion and extension--encountered in normal hair fracture. This paper provides background about a test method that does measure an amalgamation of these three elements, and gives examples of its use to evaluate a new ingredient for hair products that increases the strenth of bleached hair.