Rolling ball viscometer: A new method for performances prediction of cationic guar derivatives
Cationic guar derivatives are widely used in 2-in-1 shampoos, often in combination with silicones, to impart conditioning benefits.
Properties such as molecular weight (Mw) and degree of substitution (DS) of cationic guars are known to have a relevant impact on the hair conditioning performance of the formulation and on the amount of deposited actives such as silicone (1, 2, 5).The aim of this work is the development of a time-saving and simple method for Mw prediction of cationic guar derivatives by means of rolling ball viscometer (RBV). The correlation between the molecular weights obtained with a RVB and the values obtained by traditional GPC methods is also shown, as well as the impact of Mw on the amount of silicone deposited onto hair fibers.
Guar gum is a natural polymer extracted from the seeds of Cyamopsis Tetragonolobus (Guar Plant). As poly-galactomannan, it is composed of a straight chains of (1→4) β-D-mannopyranosyl (Man) units linked with (1→6) α-D-galactopyranosyl residue as a side chain. The ratio of Man to Gal is about 2:1 and the average molecular weight can reach or exceed 2.000.000 Da (3).
Both Gal and Man units exhibit a couple of cis-hydroxyl group that, along with the branched non-linear chain structure, make the guar galactomannan soluble in cold water and easily reactive with several chemicals.
Cationic guar gum derivatives
Guar Hydroxypropyltrimonium Chloride are quaternary ammonium derivatives of guar gum (figure 2) widely used in 2-in-1 shampoos. These cationic guar derivatives interact with keratin (4) providing a conditioning effect and reducing the negative effects of soaps and surfactants.
2-in-1 shampoos are designed to remove and solubilise soil, as traditional shampoos, and simultaneously provide conditioning benefits such as improved comb ...