1614
Ind. Eng. Chem. Res. 1997, 36, 1614-1621
Mixture Design Approach to PEG-PPG-PTMG Ternary Polyol-Based Waterborne Polyurethanes Chien-Hsin Yang Department of Chemical Engineering, Kung Shan Institute of Technology, Tainan, Taiwan, Republic of China
Yat-June Li and Ten-Chin Wen* Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan, Republic of China
A systematic modeling analysis for polyaddition of isophorone diisocyanate to poly(oxyethylene) glycol, poly(oxypropylene) glycol, and poly(oxytetramethylene) glycol (PEG-PPG-PTMG) ternary polyol-based waterborne polyurethane (PU) synthesized by a modified acetone process was performed. Using a mixture of experimental designs, empirical models are fitted and plotted as contour diagrams which facilitate revealing the synergistic/antagonistic effects between the mixed polyols. The results indicate that each component demonstrates different performances in either binary (PEG-PPG, PPG-PTMG, and PEG-PTMG) or ternary (PEG-PPG-PTMG) systems with the PTMG-based waterborne polyurethane, which is the best material for film tensile strength and ultimate elongation. Particle size analysis shows that finer particles are obtained in the dispersion of PEG-containing waterborne polyurethane while the dispersion behavior of PEG-rich waterborne PU exhibits the water-soluble polymer plastisol; in contrast, larger particles are achieved in the dispersion of PTMG (or PPG)-rich waterborne PUs, which demonstrates the polymer latex behavior. Introduction An aqueous polyurethane (PU) dispersion is a binary colloidal system in which PU particles are dispersed in a continuous water phase. Particle size is variable from approximately 1 to 5000 nm and has a direct impact on PU dispersion stability in which the dispersion with large average particle sizes (>1000 nm) is generally unstable with respect to sedimentation. Smaller average particle sizes (
