Synthesis and super retarding performance in cement production of diethanolamine modified lignin surfactant

The diethanolamine modified lignin (DML) was synthesized by lignin, chloromethyloxirane and diethanolamine, and firstly used for the production of Portland cement. Cement mortars were tested for the standard consistency, setting times and mechanical properties. The results showed that DML improved the grindability and particle size distribution efficiently, and the cement mortars made with DML exhibited excellent mechanical properties. In contrast to unmodified lignin, it was found incidentally that DML not only had excellent grinding performance, but also showed strong and unique retarding effect. The retarding mechanism mainly attributed to steric hindrance of molecular structure and electrostatic interactions of anchoring groups adsorbed on the surface of cement during the hydration process, and just the synergistic effects retarded further hydration of cement.