Slouf Miroslav, Steinhart Milos, Nemecek Pavel, Gajdosova Veronika, Hodan Jiri
Institute of Macromolecular Chemistry of the Czech Academy of Sciences, Heyrovsky Sq. 2, 16206 Prague, Czech Republic.
Materials (Basel). 2023 Jan 15;16(2):834. doi: 10.3390/ma16020834.
We compared the results of various microscale indentation creep (microcreep) measurements with macroscale tensile creep (macrocreep) measurements of three common polymers: high-density polyethylene (PE), polypropylene (PP), and polystyrene (PS). The main objective was to verify if the short-term microcreep experiments could predict long-term macrocreep behavior of the selected polymers, whose properties ranged from very soft and ductile (PE) to very hard and brittle (PS). The second objective was to compare several creep predictive schemes: the empirical power law model (PL) and several types of phenomenological elasto-visco-plastic models (EVP). In order to facilitate this task, we developed a universal program package named MCREEP, which fits PL and EVP models to both tensile and indentation creep data. All experimental results and theoretical predictions documented that: (i) regardless of the creep experiment type, both micro- and macrocreep resistance increased in the following order: PE < PP < PS, (ii) the short-term microcreep experiments could be used to predict qualitatively the long-term macrocreep behavior, and (iii) the simple empirical power law model yielded better predictions of long-term creep behavior than the more sophisticated elasto-visco-plastic models.
我们将三种常见聚合物——高密度聚乙烯（PE）、聚丙烯（PP）和聚苯乙烯（PS）的各种微观尺度压痕蠕变（微蠕变）测量结果与宏观尺度拉伸蠕变（宏蠕变）测量结果进行了比较。主要目的是验证短期微蠕变实验是否能够预测所选聚合物的长期宏蠕变行为，这些聚合物的性质范围从非常柔软且有延展性（PE）到非常坚硬且脆（PS）。第二个目的是比较几种蠕变预测方案：经验幂律模型（PL）和几种类型的唯象弹黏塑性模型（EVP）。为了便于完成这项任务，我们开发了一个名为MCREEP的通用程序包，它能将PL和EVP模型与拉伸蠕变数据和压痕蠕变数据进行拟合。所有实验结果和理论预测都表明：（i）无论蠕变实验类型如何，微蠕变和宏蠕变抗性均按以下顺序增加：PE < PP < PS，（ii）短期微蠕变实验可用于定性预测长期宏蠕变行为，以及（iii）简单的经验幂律模型比更复杂的弹黏塑性模型能更好地预测长期蠕变行为。
