反应型聚硅氧烷改性聚氨酯水分散体的合成及性能

采用N-[(1,1-二甲基-2-乙酰基)乙基]-β-二羟乙氨基丙酰胺(DDP)和双羟丙基封端聚硅氧烷(PDS)合成了反应型聚硅氧烷改性聚氨酯水分散体。测定了水分散体的黏度、表面张力、粒径、粒径分布及储存稳定性;观察了水分散体中粒子的聚集状态及胶膜断面的相分离形态;研究了水分散体成膜后胶膜的耐水和耐溶剂性能、凝胶含量、拉伸强度、断裂伸长率及热失重情况。实验结果表明,水分散体的黏度及表面张力随DDP含量的增加而增大,加入PDS后水分散体的黏度及表面张力减小;加入DDP和PDS均能提高胶膜的热稳定性;成膜时的交联反应及加入PDS显著提高了膜的耐水、耐溶剂性能和凝胶含量等性能,与聚氨酯水分散体相比,吸水率最大下降了45.83%,吸甲苯率最大下降了15.53%,凝胶质量分数最大增加了9.62%。

Preparation and Properties of Reactive Aqueous Polyurethane Dispersion Modified by Polysiloxane

Aqueous dispersions of reactive polyurethane modified by polysiloxanes were prepared from N-[(1,1-dimethyl-2-acetyl)ethyl]-β-dihydroxyethylamino propanamide(DDP) and α,ω-bis(3-hydroxypropyl)-terminated polysiloxane(PDS). Viscosity, surface tension, particle size, particle size distribution, particle morphology and storage stability of aqueous dispersions were investigated. The water resistance, solvent resistance, gel content, tensile strength, elongation at break, morphology of fractural section and thermal stability of prepared latex films of aqueous dispersions were also studied. The viscosity and surface tension raise with increase of DDP content in aqueous dispersions and reduce with increase of PDS content. Thermal stability of the films increases with incorporation of either DDP or PDS. Water resistance, solvent resistance and gel content of films are distinctly enhanced by crosslinking reaction during film formation. Compared with aqueous dispersion of sole polyurethane, water absorption of the latex film decreases by 45.83%, toluene adsorption decreases by 15.53% and gel content increases by 9.62% for the samples with the best performance.