水性聚氨酯脲-丙烯酸酯膜的表面性能

Surface properties of films prepared with aqueous polyurethaneurea-acrylate dispersions

用预聚物分散 -原位聚合法合成了聚氨酯脲 -丙烯酸酯(PUA)水分散液。用ATR -FTIR和ESCA技术表征了PUA水分散液在玻璃基材上成膜后的表面结构和组成 ,测定了不同液体在PUA膜表面上的接触角及PUA膜的耐磨性。结果表明,PUA成膜时与空气接触面和与玻璃接触面的表面组成和耐磨性接近于聚氨酯脲(PUU)的表面特性。此外 ,在PUA膜中PUU和聚丙烯酸酯的组成呈“双向梯度”分布 ,即在沿膜的2个表面方向PUU的含量均逐渐增加 ,而聚丙烯酸酯的含量逐渐降低。根据观察到的实验现象 ,探讨了PUA水分散液的成膜机理。

Aqueous polyurethaneurea-acrylate(PUA) dispersions were prepared via prepolymer dispersing - in site polymerization method. The surface layer structure and composition of PUA films were characterized by attenuated total reflection - Fourier transfer infrared (ATR-FTIR)and X-ray photoelectron spectroscopy. The contact angles of various liquids on the films and the wear resistance were tested. The results showed that the ATR-FTIR spectra for the surfaces of PUA contacted with both air and glass were similar to those of pure polyurethaneurea(PUU). The surface element composition and wear resistance of PUA film were also similar to those of pure PUU. It was found that the composition of PUU and polyacrylate in PUA hybrid film distributed in “double direction gradient”, i.e. the content of PUU gradually increased in both surface directions of PUA film while the amount of polyacrylate decreased. Based on the observed results, a film formation mechanism of aqueous PUA dispersion was discussed.