Abstract
The objective of the work was to develop a novel self cross-linking polymer capable of enhancing hair strength with fast and long-lasting effects. Our initial approach was to synthesize a homopolymer possessing reactive alkoxysilyl groups in order to effect chemical cross-linking of the polymer chains on individual hair fiber after application. Such a cross-linking reaction is accelerated by moisture and heat. This methodology proved to be successful to result in the formation of a film with high durability against repeated shampoos. Furthermore, we improved this initial polymer by incorporating other functional groups. In particular, we prepared copolymers of alkoxysilane and (1) methylmethacrylate, to increase the Tg of the polymer, (2) methyl siloxane units, to increase the flexibility, and (3) trimethylammonium units, to enhance the affinity of the polymer to hair. The quaterpolymer containing these four functional groups in suitable ratios was shown to form rapidly a film coated individual hair fiber as an “artificial cuticle, ” improved hair strength without film cracking and smoothed the texture of the hair. The performance of the polymer was evaluated by a bending test to estimate its resilience and the durability against repeated shampoos. Subsequent field tests on human hair confirmed that the formulations containing this polymer succeeded in improving hair manageability and healthy appearance, creating volume, and keeping the hairstyles ideally for an extended time period.
