Synthesis of 1,4-Butanediol di(3-Diethylamino-2-Hydroxylpropyl Alcohol) Ether and Cationic Waterborne Polyurethane with High Solids Content

A novel hydrophilic cationic chain extender, 1,4-butanediol di(3-diethylamino-2- hydroxylpropyl alcohol) ether (BDE), was successfully prepared, and then a series of lateral-chain-type cationic waterborne polyurethanes (CWPUs) with high solid content was synthesized. Compared with the traditional cationic chain extender, N-methyl diethanol amine (MDEA), BDE with lateral amino groups shows more efficient hydrophilicity and ionization properties. CWPUs prepared from BDE possess lower viscosity, smaller particle size, and larger zeta-potential. As predicted, stable CWPU latexes with higher solids content (50%) and lower hydrophilic group content were achieved. Further study indicated that other properties, including the molecular weight, glass transition temperature, thermal stability, and mechanical properties, of lateral-chain-type CWPUs were similar or superior to those of main-chain-type ones; no negative effect could be observed.