五氧化二磷改性水性环氧树脂的合成及性能

为获得具有良好表面活性的水性环氧树脂，采用五氧化二磷为磷酸化试剂对环氧树脂进行改性，并对此磷酸化工艺过程进行优化。从反应投料比、时间、温度等主要因素考察了反应条件对产物环氧值和单双酯含量的影响，确定了较佳的反应条件：反应投料摩尔比n（E20）∶n（P2O5）=1.2∶1，反应时间为3 h，反应温度为85 ℃。此工艺条件下制备产物的环氧值为0.057 mol/100 g，单酯含量为0.44 %，双酯含量为0.56 %。使用红外光谱仪、核磁共振谱仪对改性环氧树脂的结构进行了表征，并对其热稳定性、乳液的黏温、黏浓特性、粒径及表面活性进行了测试。结果表明，改性后样品的分子结构中有部分环氧键断裂，同时有磷酸单双酯官能团的出现，说明合成了新的产物；改性环氧树脂的热稳定性较好；乳液的平均粒径较小；乳液质量分数低于10 %时，其黏度几乎不受质量分数的影响，具有较好的表面活性；乳液质量分数为0.5 %时，乳液的表面张力最小。

Synthesis and Properties of Waterborne Epoxy Resin Modified with P2O5

In order to obtain waterborne epoxy resin with a high surface activity, the epoxy resin was modified by phosphorus pentoxide as a phosphorylation reagent, and the phosphorylation process was optimized. The effect of reaction conditions on the epoxy value, monoester content and diester content of resultant product was investigated with respect to the main influence factors such as reaction feed ratio, reaction time and temperature. The optimum reaction conditions were determined as an E20/P2O5 molar ratio of 1.2/1, a reaction temperature of 85 ℃ and reaction time of 3 h. The synthesized product achieved an epoxy value of 0.057 mol/100 g, a monoester content of 0.44 wt % and a diester content of 0.56 wt % under these conditions. The chemical structure of modified epoxy resin was characterized by Fourier-transform infrared spectroscopy and NMR spectrometer, and their thermal stability, viscosity-temperature, viscosity-concentration, particle size and surface activity were also investigated. The results indicated that there was partial breakage of epoxy bonds occurring in the molecular structure of the modified epoxy resin, followed by an appearance of monoester and diester functional groups of phosphoric acid. These results suggested that this new modified epoxy resin was synthesized successfully, and it exhibited a good thermal stability and a small average particle size in emulsion is smaller. When the mass fraction of emulsion was lower than 10 wt %, the epoxy resin showed a high surface activity and its viscosity was almost not influenced by the mass fraction. Moreover, the emulsion presented a minimum surface tension at a mass fraction of 0.5 wt %.