新型含醛基两性聚氨酯乳液的制备与表征

以异佛尔酮二异氰酸酯(IPDI)、聚四氢呋喃醚二醇(PTMG)、2,4-二羟基苯甲醛(DDBA)、2,2-二羟甲基丙酸(DMPA)和N-甲基二乙醇胺(N-MDEA)为原料,通过加成反应制备了含醛基两性聚氨酯乳液(AAPU)。考察了r值(IPDI中的—NCO与其他原料中总羟基的物质的量的比值)以及亲水扩链剂(DMPA)用量对乳液粒径及稳定性的影响。利用紫外光谱(UV)、红外光谱(FTIR)对AAPU进行了结构表征,通过纳米粒度仪、透射电镜和Zeta电位分析仪对乳胶粒的粒径大小、形貌和带电情况进行了测定。结果表明:产物具有预期的结构。r值控制为1.20,DMPA用量为5%(以原料的总质量为基准,下同)时,所合成AAPU的平均粒径为42.6 nm,等电点为5.16,乳胶粒外形呈较规则球形;由于AAPU表现为两性,它可在非金属鞣制体系的复鞣加工中作为复鞣剂,有望提高皮革与阴离子湿整饰材料的结合能力。

Preparation and characterization of a novel amphoteric polyurethane emulsion containing aldehyde group

New amphoteric polyurethane emulsions(AAPU) containing aldehyde group were prepared by polyaddition reaction usingisophoronediisocyanate(IPDI), polytetrahydrofuran glycol (PTMG),2,4-dihydroxybenzaldehyde(DDBA),2,2-dihydroxymethylpropionic acid(DMPA) and N-methyldiethanolamine (N-MDEA) as raw materials. The effects of hydrophilic chain extender and r value on the particle size and stability of emulsions were investigated. The structure of AAPU was characterized by UV and FT-IR. The size, morphology and electrification of latex particle were measured by nano particle size meter, transmission electron microscopy and Zeta potential analyzer. The results show that the products have the expected structure. Average particle size of the as-prepared AAPU is 42.6 nm and its isoelectric point is 5.16 while the value of r and the dosage of DMPA were controlled as 1.2 and 5%, respectively. Furthermore, because the emulsion is amphoteric,it is beneficial to improve the binding capacity between leather and anion wet-finishing materials in the retanning process of non-metallic tanning system as the retanning agent.