Abstract

We synthesize siloxane-urethane copolymer aqueous dispersions by using hydroxypropyl terminated polydimethysiloxane (HAS) and hydrohxypolyester terminated polydimethylsiloxane (PES) as siloxane monomers and dimethylol propionic acid (DMPA) as intrachain emulsifier. The stable dispersions have the average sizes from 24 to 59 nm dependent on the reaction conditions. From the dispersions, the transparent films with the improved hydrophobicity are prepared. The water contacting angels of these films are enhanced by increasing the siloxane contents. In order to reveal the influences of the different chemical structures of siloxane, these films are also investigated about the UV-vis spectrum, tensile property, topography, and glass transition. It is obtained that the use of PES can obtain the films with better light transmission, around 95%. It is observed by atom force microscope that the as-synthesized siloxane-urethane copolymer films display less phase separation, agreeing well with the high transparency. Moreover, the rheological tests and model calculations are carried out to illustrate the effects of DMPA concentrations on the viscosities and correlation to the dispersion particle sizes. The as-synthesized aqueous nanodispersions promise to be used for the transparent coatings of hydrophobicity.

摘要

我们以羟丙基封端的聚二甲基硅氧烷（HAS）和羟基聚酯封端的聚二甲基硅氧烷（PES）为硅氧烷单体，二羟甲基丙酸（DMPA）为链内乳化剂，合成了硅氧烷-氨基甲酸酯共聚物水分散体。取决于反应条件，稳定的分散体具有 24 至 59 nm 的平均尺寸。由分散体制备具有改进疏水性的透明薄膜。这些薄膜的水接触角通过增加硅氧烷含量而提高。为了揭示硅氧烷不同化学结构的影响，还研究了这些薄膜的紫外-可见光谱、拉伸性能、形貌和玻璃化转变。结果表明，使用PES可以获得透光性较好的薄膜，达到95%左右。原子力显微镜观察发现，合成后的硅氧烷-氨基甲酸酯共聚物薄膜相分离较少，与高透明度相吻合。此外，进行流变测试和模型计算以说明 DMPA 浓度对粘度的影响以及与分散体粒径的相关性。合成的水性纳米分散体有望用于疏水性透明涂层。