Abstract
A series of polyurethaneurea (PUU) aqueous dispersions, which were stable at ambient temperature for more than 1 year, were prepared with C 36‐dimer‐fatty‐acid‐based polyester polyol, isophorone diisocyanate, dimethylol propionic acid, and ethylenediamine. The particle size of all these PUU (DPU) aqueous dispersions (<100 nm) was less than that of comparable specimens, that is, poly‐(neopentyl glycol adipate) polyester‐polyol‐based PUU (APU) aqueous dispersions, and the polydispersity index was very narrow (≤1.13). The films prepared with the DPU aqueous dispersions exhibited excellent waterproof performance, such as low amount of water absorption (1.3 wt%), and good mechanical properties (hardness and tensile strength), resulting from the strong hydrogen bonding in urea carbonyl groups and the perfect ordered structure of hard segments compared with those prepared with the APU aqueous dispersions. The surface hydrophobicity of the films prepared with modified DPU aqueous dispersions, which were modified with a fluorinated polyacrylate emulsion, was excellent, as the water contact angle on the surface of such films rose up to 100. The mechanical properties of such modified DPU films were further enhanced.
Highlights
Waterborne polyurethane (PU) and PUU are widely used in coatings and adhesives since they are nontoxic and environmental
Hourston et al [3] found that organic solvent resistance performance for a waterborne PU film prepared with difunctional poly(tetramethylene oxide) polyol was better than that prepared with difunctional PPG
The fluorinated polyacrylate (PBF) emulsion composed of butyl acrylate (BA) and 2-[(perfluorononeny1)oxyl]ethyl methacrylate (FNEMA) was prepared with ammonium persulfate (APS) as initiator and sodium lauryl sulfate/ammonium perfluorooctante (SDS/APFO) as a complex emulsifier in water
Summary
Waterborne polyurethane (PU) and PUU are widely used in coatings and adhesives since they are nontoxic and environmental. The water resistance and mechanical properties of the waterborne PU and PUU films can be enhanced by varying the structure of the soft and hard segments in PU or PUU. K. Kim [1] prepared a waterborne PU with a mixture of difunctional poly(tetramethylene adipate) polyol and difunctional poly(propylene oxide) polyol (PPG) as soft segment, and found that the PU film with a higher PPG content displayed better mechanical properties. Yang et al [5] prepared a series of polyester-based waterborne PUUs with well-defined hard segments, and found that the waterproof and mechanical properties for these PUU films were enhanced significantly. The PUU aqueous dispersions based on DFA and modified with a fluorinated polyacrylate emulsion were prepared, and it is found that the water repellence property and the mechanical properties of their films are further enhanced
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