Cationic Lignin Derivatives in Hair Conditioners: Formulation Development and Rheological Modeling

Abstract

Replacing petrochemical-based cationic conditioning polymers with renewable alternatives is a key challenge in the redesign of more sustainable hair care products. In this work, cationic lignin-derivatives, prepared via a single-step cationization process using 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) were explored as alternatives to petrochemical-based cationic conditioning agents in hair conditioning products. Formulations were prepared using either these derivatives or a widely used synthetic cationic polymer (polyquaternium-11, PQ11) and characterized in terms of their physicochemical and rheological properties, and stability. Replacing PQ11 with cationic lignin derivatives did not affect the stability or the physicochemical properties of the formulations. The effect of the formulation components on the viscosity was systematically studied using a design of experiments, resulting in a predictive model describing the relationship between composition and viscosity. In addition, the lignin-based conditioners exhibited higher UV absorption than a commercial conditioner reference, with a 15-fold relative UV absorption. A preliminary proof-of-concept application on hair demonstrated improved definition and reduced frizz, supporting the potential of cationic lignin derivatives as alternative biobased conditioning agents.