内交联型淀粉改性水性聚氨酯固沙剂的制备

文章以甲苯二异氰酸酯(TDI)、聚氧化丙烯二醇(PPG)为基本原料,二羟甲基丙酸(DMPA)为亲水化改性单体、三羟甲基丙烷(TMP)为扩链剂通过预聚体法制备了淀粉改性水性聚氨酯环保型固沙剂,研究了淀粉用量对固沙剂乳液及其所成胶膜性能的影响。研究结果表明:在扩链聚合时加入可溶性淀粉,可以得到稳定的聚氨酯乳液;随着可溶性淀粉用量的增加,乳液的粘度增加,粒径呈增大趋势,胶膜拉伸强度减小;动态热力学分析显示胶膜储能模量E’随着淀粉含量的增加而减小,而玻璃化转变温度升高;保水实验显示保水效果随淀粉含量的增加而提高。当可溶性淀粉与纯聚氨酯的质量比为10%时,胶膜的拉伸强度和断裂伸长率分别为16.7 MPa和662%,而应用此配比固沙液的沙土在测试条件下10 h的失水率仅为55.7%,达到固沙剂保水性和胶膜力学性能之间较好的平衡。

Preparation of Starch Modified Ecological Sand-fixing Agent

Waterborne polyurethane sand-fixing agent with different contents of soluble starch were prepared via the prepolymer method using toluene diisocyanate(TDI),polyoxypropylene glycol(PPG)as base materials and dimethylol propionic acid(DMPA)as hydrophilic monomer,trimethylolpropane as chain-extending reagent respectively.Influence of soluble starch on the performance of polyurethane emulsion and corresponding resulted sheets was investigated.Results showed that stable emulsions were successfully prepared as soluble starch was added during chain-extending phase.Viscosity and average particle size of the emulsion were increased with increasing dosage of soluble starch,while tensile strength was reduced with increasing dosage of soluble starch.Energy storage modulus was found to decrease with increasing concentration of soluble starch via dynamic mechanical analysis while glass transition temperature was increased.Addition of starch helped to enhance the ability of water conservation.When the weight ratio of soluble starch to polyurethane was about 10%,tensile strength and elongation at break of the corresponding sheet were 16.7 MPa and 662% respectively.Water conservation result showed water loss was only 55.7% when emulsion was used as sand-fixing agent which indicated the balance of mechanical properties and water conservation can be acquired at this composition.