This work documents the first account of advanced mechanical properties of six commercial lipsticks, some of which serve as market leads. We systematically studied their nonlinear viscoelastic properties under large amplitude oscillatory shear deformations. At large strains, all lipsticks showed intercycle strain softening, the extent of which initially depended on the prototype in the nonlinear regime. This behavior, markedly, was absent after the crossover of the dynamic moduli. Parameters obtained from the strain amplitude sweeps, i.e., the intrinsic elastic modulus and the stress maximum, demonstrated distinct prototype dependence. The Lissajous plots and the dimensionless nonlinear indices were determined using the MITlaos software. They showed intracycle elastic strain stiffening and viscous shear thinning. The angular oscillation frequency directly influenced the linear viscoelastic measures of all the benchmark lipsticks, and the nonlinear properties of only a few benchmark ones. The current study generates standard nonlinear rheology data that can be associated with the lipstick sensory attributes and typical tribological parameters. This may serve as an effective way to examine the transition from the initial spreading to the post-application sensation.

中文翻译：

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工业标杆口红在大尺度变形下的机械响应

这项工作首次记录了六种商业唇膏的高级机械性能，其中一些是市场领先者。我们系统地研究了它们在大振幅振荡剪切变形下的非线性粘弹性。在大应变下，所有口红都表现出循环间应变软化，其程度最初取决于非线性区域中的原型。显然，这种行为在动态模量交叉后不存在。从应变振幅扫描获得的参数，即固有弹性模量和应力最大值，表现出明显的原型依赖性。使用 MITlaos 软件确定 Lissajous 图和无量纲非线性指数。它们显示出循环内弹性应变硬化和粘性剪切变稀。角振荡频率直接影响所有基准口红的线性粘弹性测量，仅影响少数基准口红的非线性特性。当前的研究生成了标准的非线性流变学数据，这些数据可以与口红感官属性和典型的摩擦学参数相关联。这可以作为一种有效的方式来检查从最初的传播到应用后感觉的过渡。