Study On Soybean Oil - Based Waterborne Polyurethane SiO 2 Subcomponent

In the past decades, with the development of industry and society, the problem of energy and environment has become increasingly prominent. Compared with conventional solvent-based polyurethane, waterborne polyurethane has outstanding advantages such as low VOC emissions and low toxicity, so the study and application on waterborne polyurethane developed rapidly. On the one hand, the study of modification on waterborne polyurethane to improve mechanical strength and water resistance has become a hot research topic. On the other hand, improving the “greenness” of waterborne polyurethane by using renewable resources to replace petroleum as raw materials has become another hot research topic about waterborne polyurethane.In this paper, soybean oil based waterborne polyurethane was prepared from renewable resource epoxy soybean oil(ESO). And then soybean oil based waterborne polyurethane/SiO2 nanocomposite was prepared by nano silica sol to the above system.This work will help to promote the development of environmentally friendly and high performance waterborne polyurethane products.In this work, epoxy soybean oil(ESO) was functionally modified with acrylic acid(AA) to yield acrylated epoxy soybean oil(AESO), which possesses C=C groups and hydroxyl groups. The hydroxyl groups of AESO may be used for preparing the waterborne polyurethane, while C=C can participate in UV curing reaction. The influence of reaction temperature, reaction time, catalyst and polymerization inhibitor on AESO had been studied. Maenwhile, for the following research of soybean oil based waterborne polyurethane(SWPU), two AESO with different functionality had been prepared by adjusting the equivalent ratio between ESO and AA, which hydroxyl group numbers were2.88 and 3.48 respectively. The analysis of the test results showed that: with triphenylphosphine as catalyst, 4-methoxyphenol as a polymerization inhibitor, and with 5h reaction time and 110 oC reaction temperature, the conversion rate of AESO can reach96%.A series of UV curable soybean oil based waterborne polyurethane(SWPU)emulsions were produced by using AESO as part of polyol resin, in wich the content of AESO in polyol resin was 0~50%. SWPU emulsions, their naturally dry coating films and UV cured caoting films had been studied. The results showed that: polyurethane emulsions were successfully modified by AESO; with 30% AESO, the tensile strength of thenaturally dry coating films is 9.8~10.8 MPa, the UV cured caoting films tensile strength is18.7 MPa. In addition, compared to waterborne polyurethane based on PPG-2000, both SWPU naturally dry coating films and its UV cured caoting films showed better performance, such as water resistance, thermal stability and pencil hardness.In this work, nano SiO2-PPG dispersion was firstly prepared. And then a series of SWPU/SiO2 nanocomposite emulsions were produced by the above nano SiO2-PPG dispersion, in which the nano SiO2 content was 1%~3.5%. When the nano SiO2 content was 1%~3%, the stability of the emulsions was good. But when the nano SiO2 content reached 3.5%, the stability of the emulsion would get worse. Our study showed that: water resistance, thermal stability and pencil hardness of the SWPU coating films were significantly improved by nano SiO2. When the nano SiO2 content was 2% and AESO content was 30%,SWPU naturally dry coating films had good mechanical properties:tensile strength was 14.86 MPa, elongation at break was 324%, and water absorption was8.52%; SWPU UV cured caoting films also had good mechanical properties: tensile strength was 18.83 MPa, elongation at break was 202%, and water absorption was 7.84%.