Synthesis and characterization of α,ω‐Bis(3‐hydroxypropyl)‐functionalized poly{dimethylsiloxane‐co‐methyl[3‐(2‐acetyl‐acetoxy)]propylsiloxane}

With the purpose to develop polysiloxane-modified waterborne polyurethane (WPU) which was expected to have better water resistance than WPU and better mechanical strength and abrasion characteristics than polysiloxane, a novel reactive polysiloxane bearing hydroxypropyl group at both chain ends and carbonyl groups at the side chain was synthesized by five-step reactions. The prepared compounds in each step were characterized; the results showed that each step synthesis was successfully carried out and objective products were achieved. This novel reactive polysiloxane combines the properties of difunctional hydroxyalkyl terminated polysiloxane and crosslinking agent. When it was incorporated with WPU, the latex film properties of reactive polysiloxane-modified WPU were investigated compared with that of pure WPU. The results indicated that siloxane segments could lower the water absorption of WPU, and that the crosslinking reaction between the dihydrazide and carbonyl group could improve the physical–mechanical characteristics of polysiloxane-modified WPU after post-added dihydrazide. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012