화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.49, No.10, 4517-4527, 2010
Preparation and Characterization of Waterborne Hyperbranched Polyurethane-Urea and Their Hybrid Coatings
A series of novel waterborne hyperbranched polyurethane-urea (WHBPU) were prepared with different chain extenders (diamine, diol, and siloxane) by a systematic reaction process. Initially, the hyperbranched polyester polyol was prepared by reacting polytetramethyleneglycol (PTMG)-1000 with 2,2-bis(hydroxymethyl) propionic acid (DMPA) in a molar ratio of 1:14 (3rd generation) at 160 degrees C by one pot synthesis. This was reacted with an adduct of isophorone diisocyanate (IPDI) and DMPA with NCO:OH mole ratio of 1.6:1. Then 50% of free NCO in these prepolymers was reacted with three different chain extenders (diol, diamine and APTES). This reaction mixture was neutralized with triethyl amine and another 50% of free NCO was chain extended with isophorone diamine during water dispersion. The obtained polyester was characterized with Fourier transform-infrared spectroscopy (FT-IR), H-1 and C-13 NMR, respectively. The properties of WHBPU and their hybrid coatings were studied by FT-IR, H-1 NMR, thermogravimetric analyzer (TGA), dynamic mechanical, and thermal analyzer (DMTA), and the contact angle measurement. TGA and DMTA results confirmed that these coatings have good thermal and mechanical properties. The onset degradation temperature of the WHBPU without APTES starts in between 200 and 250 degrees C, whereas the APTES chain extended WHBPU starts at 250 degrees C. T-g of WHBPU without APTES varies between 106 and 126 degrees C, while 129 degrees C for APTES chain extended WHBPU. The conditions for the reproducible preparation of suitable products have been found and optimized. They enable the tuning of their properties according to the intended use. The aim of the prepared WHBPU films is long-term use as thermal and mechanical resistant systems. Along with these property APTES crosslinked system, the hydrophobic silica-rich surface is likely to belnhibited the hybrid films upon exposure to an aqueous environment.