Radebaugh G W, Simonelli A P
J Pharm Sci. 1983 Apr;72(4):415-22. doi: 10.1002/jps.2600720423.
This study presents the results of an investigation of the viscoelastic properties of anhydrous lanolin USP, as determined by dynamic mechanical testing. The elastic shear modulus (G'), viscous shear modulus (G"), and loss tangent (tan delta) were determined as a function of shear frequency, nu, (0.01--10.0 Hz) and temperature, T, (0--30 degrees). These viscoelastic parameters were found to be temperature and shear frequency dependent. Up to 100-fold changes in shear moduli and tan delta values were observed with appropriate changes in T and nu. Many of the observed properties are also characteristic of high molecular weight polymers and can be attributed to a high degree of molecular structure. It was found that dynamic mechanical testing was a sensitive tool for measuring structural changes, and was especially useful in detecting a major structural transition well below the accepted melting temperature of anhydrous lanolin.
本研究展示了通过动态力学测试测定的无水美国药典级羊毛脂粘弹性特性的调查结果。弹性剪切模量（G'）、粘性剪切模量（G"）和损耗角正切（tan δ）作为剪切频率ν（0.01 - 10.0 Hz）和温度T（0 - 30摄氏度）的函数被测定。发现这些粘弹性参数取决于温度和剪切频率。随着T和ν的适当变化，观察到剪切模量和tan δ值有高达100倍的变化。许多观察到的特性也是高分子量聚合物的特征，并且可归因于高度的分子结构。发现动态力学测试是测量结构变化的灵敏工具，并且在检测远低于无水羊毛脂公认熔点的主要结构转变方面特别有用。
