Synthesis and properties of block and graft waterborne polyurethane modified with α,ω‐bis(3‐(1‐methoxy‐2‐hydroxypropoxy)propyl)polydimethylsiloxane and α‐N,N‐dihydroxyethylaminopropyl‐ω‐butylpolydimethylsiloxane

In this study, α,ω‐bis(3‐(1‐methoxy‐2‐hydroxypropoxy)propyl)polydimethylsiloxane and α‐N,N‐dihydroxyethylaminopropyl‐ω‐butylpolydimethylsiloxane were used to prepare block and graft waterborne polyureathane–polysiloxane copolymer dispersions. α,ω‐bis(3‐(1‐methoxy‐2‐hydroxypropoxy)propyl)polydimethylsiloxane was synthesized by hydrosilylation, methoxylation and equilibrium reactions; α‐N,N‐dihydroxyethylaminopropyl‐ω‐butylpolydimethylsiloxane was synthesized via hydroxyl protection, alkylation, anionic ring‐opening polymerization, hydrosilylation, and deprotection. Block and graft waterborne polyurethane–polysiloxane copolymer dispersions were prepared by the reaction of poly(propylene glycol) (PPG), toluene diisocyanate (TDI), 2,2‐dimethylol propionic acid (DMPA), 1,4‐butanediol (BDO), α,ω‐bis(3‐(1‐methoxy‐2‐hydroxypropoxy)propyl)polydimethylsiloxane, and α‐N,N‐dihydroxy‐ethylaminopropyl‐ω‐butylpolydimethylsiloxane. The water absorption of block and graft waterborne polyurethane–polysiloxane copolymer films decreased from 163.9 to 40.2% and 17.3%, respectively, when percent of polysiloxane (w/w) increased from 0 to 5%, and the tensile strength of the block waterborne polyurethane–polysiloxane copolymer films decreased while the tensile strength of graft waterborne polyurethane–polysiloxane copolymer films increased with increase of percent of polysiloxane. For graft waterborne polyurethane–polysiloxane films, the tensile strength would decrease when percent of polysiloxane was more than 3%. POLYM. ENG. SCI., 54:805–811, 2014. © 2013 Society of Plastics Engineers