In this study, the mechanical properties of isotactic polypropylene (iPP) materials with different crystallinities at room and elevated temperatures were investigated. In order to obtain samples with a certain range of crystallinity, and to ensure a uniform microstructure of these samples, the iPP samples obtained by injection molding required melt compression molding and controlled annealing. In the macromechanical studies, the experimental results showed that the storage modulus and Young's modulus of polypropylene were sensitive to the service temperature. The crystallinity also had a great influence on this relationship. A function was proposed to evaluate the dependence of the Young's modulus of polypropylene on initial crystallinity and service temperature, and tested based on experimental data. The Young's modulus of iPP is reduced by about 90% when the service temperature rises from 25 to 125 °C. Moreover, the reduced value in Young's modulus between polypropylene having the highest and lowest crystallinity was reduced from 214.55 to 56.75 MPa. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48581.

中文翻译：

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聚丙烯杨氏模量的量化：初始结晶度和使用温度的影响

在这项研究中，研究了在室温和高温下具有不同结晶度的全同立构聚丙烯（iPP）材料的机械性能。为了获得具有一定结晶度范围的样品，并确保这些样品具有均匀的微观结构，通过注射成型获得的iPP样品需要熔融压缩成型和受控退火。在宏观力学研究中，实验结果表明聚丙烯的储能模量和杨氏模量对使用温度敏感。结晶度也对这种关系有很大的影响。提出了评估聚丙烯的杨氏模量对初始结晶度和使用温度的依赖性的功能，并基于实验数据进行了测试。年轻人' 当使用温度从25°C升至125°C时，iPP的s模量降低约90％。此外，具有最高和最低结晶度的聚丙烯之间的杨氏模量的降低值从214.55MPa降低至56.75MPa。分级为4 +©2019 Wiley Periodicals，Inc.J.Appl。Polym。科学2020，137，48581。