Studies On The Synthesis And Application Of MPEG/PTMG Waterborne Block Type Of Polyurethane Surfactants

Waterborne polyurethane, which has excellent performance of both amphiiphilicmaterials and polyurethane material, has a very application prospects. It can be used aswaterproof and moisture permeable material, polymer surfactant and medical materials, etc.,but it hasn’t been studied deeply in our country. It is very significant to study polyurethanesurfactants.Two kinds of block polyurethane surfactants including two block polyurethanesurfactants and three block polyurethane surfactants were synthesized by molecularstructure design. Two block polyurethane surfactants and three block polyurethanesurfactants were synthesized by2,4-toluene dissocyanate(TDI), methoxy polyethyleneglycols(MPEG), polyoxytetramethylene(PTMG-1000, PTMG-2000) as feedstock. Thesolution properties and micellar system of two kinds of block polyurethane surfactants werestudied which decided the difference of application fields. The experimental results were asfollows:(1) The influential factors were discussed. The products are characterized by IR and1HNMR.The cloud point of two block polyurethane surfactants decreased gradually with theincrease of hydrophobic segment, the value was81.0℃and73.6℃. As well, the cloudpoint of three block polyurethane surfactants decreased gradually with the increase ofhydrophobic segment, the value was85.7℃and81.3℃. The cloud point of three blockpolyurethane surfactants was greater than two block polyurethane surfactants.(2) The value of surface tension of block polyurethane surfactants was measured bysuspension loop method under different conditions. The experimental results show that:①The critical micelle concentration(CMC) and surface tension was decreasing with thehydrophobic segment growth in distilled water, the value was5.12×10-6mol·L-1,3.86×10-6mol·L-1,7.94×10-5mol·L-1,6.31×10-5mol·L-1. Two block polyurethane surfactantshad the lower surface tension and CMC than three block polyurethane surfactants.②The surface tension and CMC of block polyurethane surfactants decreased with the temperatureincreasing, when temperature was below the cloud point.③The different electrolyte haddifferent effect on surface tension and CMC. The effect of surface tension and CMC wasvery small when the concentration of electrolytes(NaCl) was in low concentration. Thesurface tension and CMC gradually decreased with the increasing of electrolytesconcentration when the concentration of electrolytes(NaCl) was in high concentration. Fordifferent charge/radius ratio of electrolyte solution, the CMC increased gradually with thecation charge/radius ratio increased at the same intensity of anion, the CMC decreasedgradually with the cation charge/radius ratio increased at the same intensity of cations.④The effect of surface tension and CMC was very small at different pH value.(3) The micellization of block polyurethane surfactants was investigated byfluorescence spectrophotometer and transmission electron microscopy. The experimentalresults show that:①The CMC measured by fluorescence method was consisted with thatdetermined by surface tension method. Environmental micropolarity of micelle showsnonpolar.②The micelle aggregation number of block polyurethane surfactants increasedgradually with the concentration increased. The micelle aggregation number of two blockpolyurethane surfactants was more than the micelle aggregation number of three blockpolyurethane surfactants.③The micelles were global and micelle volume growed as theblock polyurethane surfactants concentration increased.(4) The emulsifying power and solubilization of block polyurethane surfactants wasstudied. The experimental results show that: Block polyurethane surfactants had perferableperformance of solubilization on methylbenzene and emulsifying power. The emulsifyingpower increased with the hydrophobic segment growth. The solubilization of three blockpolyurethane surfactants was greater than the solubilization of two block polyurethanesurfactants.