Modification Of Double Hydroxyl Methyl Silicone Oil, Fluorine Polyether Modified IPDI-Polyether Waterborne Polyurethane

A series of waterborne polyurethane was synthesized through Polytetramethylene ether glycol(PTMG), isophorone diisocyanate(IPDI) and 1,4-butanediol(1,4-BDO) and dimethylol propionic acid(DMPA) as monomers, double hydroxyl terminated polydimethylsiloxane(PDMS) and double hydroxyl terminated perfluorinated polyether oil(E10-H) as soft segment modified agent, triethylamine(TEA) as a salt forming agents, dimethyl acetamide(DMAC) and acetone as solvent and water as dispersing agent, by changing difference of [-NCO]/[-OH](R value), and the change with different contents of PDMS and E10-H. The experimental basis is from formulations of leather top finishing coating, therefore the experiment’s requirement and purpose is to make the basic formula to exploration and optimize the water property.Firstly, the structural changes of the materials were characterized by attenuated total reflection infrared spectroscopy, and it was found that the characteristic absorption peak of 1660cm-1 urea carbonyl group increased with the increment of R value, the characteristic absorption peak of Si-C at 803cm-1 increased with the increment of PDMS content, and the absorption peak of 1400-1100cm-1 occurred apparent diffusion phenomenon with the increment of E10-H content. The particle size of the waterborne polyurethane emulsion was measured by light scattering and it was found that the particle size and the dispersion index increased with R value. The introduction of PDMS increased the dispersion index of the emulsion, but decreased the surface tension. The properties of the WPU film material was analyzed by dynamic mechanical performance analysis, thermo-gravimetric analysis and the rheological properties analysis. It was found that the glass transition temperature of materials was lower than the room temperature 50℃. The film material can be used as elastomer because of good flexibility, higher decomposition temperature and shear resistance. Cryogenically brittle fractured cross section of samples were observed by scanning electron microscopy. It was found that a pure polyurethane section is smooth, but the sections of PDMS or E10-H modified polyurethane materials were rough and slight phase separation zone occurred. The section of PDMS modified polyurethane appeared to micron phase region, but this phase region situation was suppressed in PDMS and E10-H modified polyurethane. It was also observed that the elongation of the film at break was the maximum 1143% with 2% PDMS content and 1.2 R value by tensile test. The hydrophobic properties of the materials were evaluated through swelling rate in the water and water contact angle. PDMS have great influence on the swelling properties of the water and can greatly reduce the water absorption rate, the minimum 24 hour water absorption rate is 12.9%, E10-H had great increment of the water contact angle, the maximum can reach 100o. XPS results show that chain segment containing F and Si elements have better surface migration ability.