Synthesis and characterization of an isocyanate-terminated hyperbranched polymer and its waterborne study

An isocyanate-terminated hyperbranched polymer (HBI) was successfully synthesized by reacting hyperbranched polyester (BoltornTM HB-20) with isophorone diisocyanate (IPDI). Gel permeation chromatography (GPC) was used to monitor the molecular weight and its distribution changes during the synthesis. The structure and composition of IPDI were characterized by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The structure of HBI was confirmed by one-dimensional 1H, 13C NMR, and distortionless enhancement by polarization transfer (DEPT) NMR spectroscopy as well as two-dimensional heteronuclear multiple bond coherence (2D-HMBC) and heteronuclear single quantum coherence (HSQC) NMR spectroscopy. Furthermore, HBI was reacted with methoxypolyethylene glycols (MPEG) to obtain a water-dispersible polyisocyanate with hyperbranched structure.