聚氨酯预聚体分散体胶粒的形成与扩链

Chain Extension and Formation of Dispersion Particle Based on Polyurethane Prepolymer

以聚丙二醇(PPG)、异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)、乙二胺(EDA)为原料合成了固含量40%的聚氨酯分散体。采用激光粒度分析仪测试了预聚体分散体胶粒形成和扩链过程中的平均粒径和粒径分布,透射电镜(TEM)表征了胶粒的形态结构。结果表明,预聚体分散体中可能存在理想胶粒、活性胶粒、可再分散胶粒,理想胶粒中的NCO处于胶粒内部,活性胶粒中的NCO处于胶粒的内部和表面;分散和扩链反应中活性胶粒之间的反应使胶粒粗化和呈双峰分布;提高预聚体nNCO/nOH、COOH%,预聚体分散体中活性胶粒增加;TEM显示聚氨酯分散体胶粒主要呈球形,部分呈不规则形态。

A series of polyurethane dispersions（PUDs） having a solid content of 40% were synthesized by prepolymer method with polypropylene glycol（PPG）,isophoronediisocyanate（IPDI）,dimethyol propionic acid（DMPA） and ethylenediamine（EDA）.The average particle size and particle size distribution were measured during different processes of formation,chain extension of prepolymer dispersion respectively by laser light scattering particle size analyzer,transmission electron microscopy（TEM） was used to measure the particles morphology.The result shows that ideal particles,active particles and redispersible particles exist in prepolymer dispersions.All free NCO groups are inside the inner space of ideal particles while some free NCO groups locate at the surface of active particles.Particles of PUDs become bigger and show double peaks distribution due to reaction between active particles during dispersing and chain extension.The number of active particles increases when nNCO/nOH and COOH% increased.TEM shows PUD particles are sphericity but a few number particles are anomalous.