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In recent years, water-based polyurethane (WPU) has received wide attention due to its excellent performance and good environmental effect. Polypropylene glycols, isophorone diisocyanate (IPDI), bis (hydroxymethyl) propionic acid (DMPA), and ethylenediamine (EDA) was synthesized anionic WPU. Situ modification and sol - gel method nano TiO , 2 modified WPU. The results are as follows: n (NCO): n (OH), increase of DMPA dosage, the tensile strength of the film increases, the elongation at break decreased; n (NCO): n (OH) increase the resistance of the film enhanced solvent resistance, micro-phase separation becomes large, n (NCO): n (OH) about 1.5, preferably emulsion stability; film solvent resistance decreases with the increase in the amount of DMPA, so to ensure the stability of the emulsion premise under should as far as possible to reduce the amount of DMPA this election DMPA amount of 5.99 to 6.8%; neutralization degree of 80 to 100%, n (NH2): n (NCO) about 0.9 WPU better overall performance; emulsion during EDA was dissolved in water, the resultant the WPU particle size distribution is narrow, has significantly improved solvent resistance and tensile strength, elongation at break is reduced, the emulsion stability is good; with the soft segment molecular weight increases, the film solvent resistance and reduced tensile strength, elongation at break increased. The silane coupling agent, titanate coupling agent, stearic acid, and their composite modifier for surface modification of nano-TiO 2 , the choice of modifier, modified conditions determined were discussed, the results show that: titanate 5%, stearic acid 20%, temperature 45 ° C, under the conditions of the reaction time of 90 min, preferably nano-TiO 2 of surface modification effect . In WPU prepared on the basis of in situ polymerization and sol - gel prepared WPU / nano-TiO 2 composite. In situ polymerization using FT-IR, UV, TEM, SEM and other characterization methods studied nano-TiO 2 Add the amount of the WPU / nano-TiO 2 Composite Emulsion film performance. The results showed that the the nano TiO 2 dosage of 0.4 to 0.6%, the nano-TiO 2 in the WPU uniformly dispersed, played a strengthening and toughening effects, and lt; 650 nm have significant UV absorption; the the WPU / nano-TiO 2 antibacterial properties of the composite coating were tested. The results showed that the coating can inhibit the growth of E. coli. Sol - gel method prepared WPU / nano the TiO 2 process conditions, hydrolysis and condensation time 150 min, TNB content of about 5 to 10%, n (H2O): n (TNB) ≥ 602 , pH between 9.5 to 10.5.
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