TA仪器Discovery 流变仪

Conventional transducers measure the strain in a compliant member and based on their stiffness, determine the torque resp. normal force (Fig. 1a). This method has several inherent disadvantages. Since the compliant member is strained, the strain has to be accounted for in determining actual sample strain. In dynamic the inertia of the moving mass of the transducer, affects the measured results at high frequences. Further, viscoelastic materials which develop normal forces, drive the cone and plate apart. This effect generates secondary flow fields and the result is an inaccurate transient normal force measurement. To overcome these problems of conventional transducer, all developments have been made towards stiffer transducers. The stiffness however is directly related to the resolution of the strain measurement of the compliant member i.e. the torque resp. force measurement. This implies that the stress resolution decreases with increasing stiffness.

震荡中的流变测量无论在应力还是应变通常都会形成强烈的信号。随着材料复杂度的增加，在样本测试中更加需要能够覆盖广泛范围的样品弹性模量（个和应力及应变）。对于动态范围由于106的，必须消除随机噪声和系统误差修正，以确保准确的结果。高速数据采集与灵活的相关技术结合，以提高低端性能流变仪。

Waterborne coatings do not have a priori, the same advantageous rheological properties as solvent-based coatings. If not formulated correctly, they are much inferior with regard to flow properties, leveling, application properties, film build, etc.. In order to obtain the desired performance, thickeners and rheological modifiers are added to improve waterborne paints. Conventional thickeners like cellulosics, high molecular weight polymers or inorganic clays increase the viscosity during application, but they provide poor spatter resistance and leveling to the paint. Associative thickeners are low molecular weight, water soluble polymers like modified alkali swellable emulsions, and provide overall good performance to a waterborne coating.

Thermoset polymers form the matrix in filled plastics and fiberreinforced composites used in a diversity of products. These range from consumer items and auto body panels to advanced composites for printed circuit boards (PCBs), aerspace structural components such as the Space Shuttle payload bay door and jet engine cowls and ducts, and expensive, high-performance sports equipment. Also, thermosets are used extensively as adhesives, molding compounds, and surface coatings, including protective solder masks for PCBs.

一个医药公司想比较两种洗液的扩散速度，以确定不同配方的作用效果。可是两种洗液的量非常少，难以用合适的方法进行表征。

In an oscillation shear experiment, the material is subjected to either a sinusoidal strain or stress and the corresponding response is measured. The ratio of the output and input signals is referred to as the transfer function or material function (Figure 1). When a sinusoidal deformation or deformation rate is applied, the material’s response is the stress. The resulting material function is either the modulus or the viscosity; if a stress is applied and the strain measured, the material function is the compliance.