Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/94895
標題: Effects of the NCO/OH molar ratio and the silica contained on the properties of waterborne polyurethane resins
作者: Wen-Jau Lee
Wei-Ting Lin
李文昭
關鍵字: NCO/OH molar ratios;Organic-inorganic hybrids;Tetraethoxysilane;Thermal properties;Waterborne polyurethane resins (WPUs)
Project: Colloids and Surfaces A: Physicochemical and Engineering Aspects, Volume 522, 5 June 2017, Pages 453-460
摘要: 
Waterborne polyurethane resins (WPUs) were synthesized with polytetramethylene ether glycol (PTMG), dimethylolpropionic acid (DMPA), isophorone diisocyanate (IPDI), triethylamine (TEA) and ethylenediamine (EDA) as the raw materials of polyol, internal emulsifier, isocyanate, neutralizer and chain extender, respectively. The NCO/OH molar ratios used for the pre-polymerization were set as 1.6/1, 1.8/1 and 2.0/1. Furthermore, tetraethoxysilane (TEOS) was added to the WPUs to prepare the WPU/silica organic-inorganic hybrids by the sol-gel process. The characteristics of WPUs prepared with different NCO/OH molar ratios, and the properties of WPU and WPU/silica films were investigated. The results show that WPUs prepared with higher NCO/OH molar ratios have suspensions with lower viscosity, smaller average particle size and smaller average molecular weight, and lead the films to have more urea and amide structure, better solvent resistance, higher tensile strength, modulus and break energy, lower molecular chain activity, and smaller damping peak height, but weaker thermal resistance. The network structure of silica can limit the activity of the soft-segment, increase the stiffness of the hard-segment and enhance the thermal resistance of WPUs films.
URI: http://hdl.handle.net/11455/94895
Appears in Collections:森林學系

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