Carboxymethyl Dextran As Biodegradable Dispersants for Automatic Dishwashing Detergents

Polymeric dispersants are additives commonly used in household cleaning products such as automatic dishwashing (ADW) and laundry detergents. Incumbent technologies such as polycarboxylates and their copolymers offer excellent cleaning performance but lack biodegradability. Therefore, these materials after use often linger in the natural environment for years to decades. Biodegradable alternatives are highly desired for these “down-the-drain” applications which would reduce environmental persistence and enable carbon circularity. Poly(aspartic acid) and carboxymethyl inulin show biodegradability but so far have limited market penetration given their unsatisfactory cleaning performance. Here we report the synthesis of carboxymethyl dextran and their use as biodegradable, high-performing dispersants for ADW detergents. Dextran is a linear, water-soluble poly(α-glucan) derived from the fermentation of sucrose from natural sources such as sugar cane. Carboxymethyl dextran was synthesized by the caustic-activated alkylation with sodium chloroacetate in water. ADW detergents with carboxymethyl dextran showed excellent anti-spotting and anti-filming performance in model citrate-based formulations. The structure‒performance relationship for optimized compositional design (e.g., degree of substitution and molecular weight) will be discussed.