A series of novel transparent mechanically strong waterborne poly(urethane‐urea)/silica nanocomposites were prepared by mixing a waterborne poly(urethane‐urea) dispersion with aqueous nanosilica, followed by slow water evaporation. This procedure is simple, environmentally friendly and energetically undemanding. The silica content in the nanocomposite film varied from 0 to 50 wt%. Based on changes of tensile characteristics, for example, Young's modulus values, three types of behavior were observed: typical elastic (0‐10 wt%), plastic (30 wt%) and ceramic‐like (50 wt% silica) materials can be prepared. However, some films feature both elastic and plastic (material with 20 wt% silica) or plastic and ceramic‐like characteristics (material with 40 wt% silica). The Young's modulus varied from 6 to 705 MPa, and the maximal tensile strength and elongation‐at‐break were 17.3 MPa and 1270%, respectively. The maximum energy‐to‐break, 60 mJ mm⁻³, was achieved for the film containing 30 wt% silica. All these materials can potentially be used as soft‐to‐hard topcoats, depending on the specific demands.

中文翻译：

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新型水性聚氨酯（尿素）/二氧化硅纳米复合材料

通过将水性聚（尿烷-脲）分散体与水性纳米二氧化硅混合，然后缓慢蒸发，制得了一系列新颖的透明的机械强度高的水性聚（尿烷-脲）/二氧化硅纳米复合材料。此过程简单，环保且对能源的要求不高。纳米复合膜中的二氧化硅含量为0至50重量％。根据拉伸特性的变化（例如杨氏模量值），可以观察到三种类型的行为：典型的弹性材料（0-10 wt％），塑料（30 wt％）和类陶瓷（50 wt％二氧化硅）材料可以准备好了。但是，某些薄膜同时具有弹性和塑料（二氧化硅含量为20 wt％的材料）或类似塑料和陶瓷的特性（二氧化硅含量为40 wt％的材料）。杨氏模量从6到705 MPa，最大抗张强度和断裂伸长率分别为17.3 MPa和1270％。最大断裂能60 mJ mm对于包含30重量％二氧化硅的膜，获得了^-3。根据具体要求，所有这些材料都可以用作软硬涂层。