The Viscoelastic Properties of Chemically Modified Alpha-Keratins in Human Hair
June 2014
in “
[Thesis]. Manchester, UK: The University of Manchester; 2014.
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TLDR Chemical modifications can alter hair's stability and flexibility, with hydrophobic interactions helping maintain structure in humid conditions.
The study investigated the viscoelastic properties of human hair after chemical modifications, specifically esterification and disulfide reduction with alkylation. Esterification was found to plasticize the hair matrix and affect the stability of intermediate filaments (IFs), with the alkyl chain length influencing plasticizing efficiency. Disulfide reduction and alkylation significantly impacted the matrix by reducing water content-dependent glass transition and IF stability, although hydrophobic interactions at high water content helped maintain IF integrity. Mechanical tests showed some restoration of stability after propylation. The study suggested that hydrophobic interactions play a role in stabilizing hair fibers at higher relative humidities and water contents, and future research could further elucidate the specific effects of these modifications.