Latex interpenetrating networks based on polyurethane, polyacrylate and epoxy resin

Firstly the polyurethane (PU)/polyacrylate (PA) latex interpenetrating networks (LIPNs) were synthesized and the miscibility of PU/PA LIPN was investigated with differential scanning calorimetry (DSC). The effects of different PU/PA composition, the blending pattern and NCO/OH molar ratios on LIPNs performance have also been characterized using DSC, wide-angle X-ray diffraction (WAXD) methods. The particle size and its distribution were determined by dynamic light scattering (DLS) instrument. It has been found that the miscibility of PU/PA LIPNs is superior to the corresponding physical polymer blending systems due to a considerable extent of interpenetration and entanglement between PU and PA latex. PU/PA LIPNs can improve water resistance of PU dispersion emulsion; however, they are inferior to corresponding solvent-based counterparts. In order to solve the problem, a new kind of novel ternary LIPN of PU/PA/epoxy (EP) resin was synthesized. The water resistance of films was improved considerably. The effects of EP resin content on water resistance and mechanical properties of films were also explored in this paper. (C) 2003 Elsevier B.V. All rights reserved.