Preparation and Properties of Waterborne Polyurethane Containing Hyperbranched Polyester Linkages

Abstract

Different generations of hydroxyl-terminated hyperbranched polyesters (HBPEs) were synthesized in sequence, all of the HBPEs based on methyl methacrylate (MMA) and diethanolamine (DEA) as AB₂ monomer and trimethylolpropane (TMP) as core molecule. Then a series of hyperbranched waterborne polyurethane dispersions (HPUs) were prepared with the 3rd generation hyperbranched polyester (HBPE-3) used as an original cross-linking agent in this article. The intrinsic viscosity of each HBPE vs temperature and properties of HPUs was studied. The experimental data indicated that, compared with the linear one, the hyperbranched HPU aqueous dispersion exhibited larger particle size and higher surface tension, when the hydroxyl-ratio was 1:6, the HPU achieved maximum particle size of 78.0 nm and surface tension of 52.48 mN/m, respectively. For the hyperbranched HPU films, the thermal stability and mechanical properties increased, resulting from the effects of the cross-linking structures in the HPU system.

Keywords:

• Cross-linking
• Hyperbranched polymer
• Mechanical property
• Surface tension

ACKNOWLEDGMENTS

This work was financially supported by China Postdoctoral Science Foundation (Grant no. 2011M500865), Jiangsu Planned Projects for Postdoctoral Research Funds (Grant no. 1002033C), fund of Jiangsu University (Grant no. 08JDG004), the Agricultural Independent Innovation of Jiangsu Province (CX(11)2032) and the Natural Science of Jiangsu Province (Grant no. BK2008247).

Notes

^a Hydroxyl mole ratio of HBPE-3 and polyester diols.