A new methodology is proposed to quantify long-chain branching (LCB) molar fraction in polypropylene (PP) systems. Gel permeation chromatography and small-amplitude oscillatory shear were employed to quantify LCB molar fraction and its influence on rheology in PP. Introduction of an increasing amount of coupling agent during extrusion leads to the formation of a proportional level of LCB molar fraction in the model PP investigated. The dependency of zero-shear viscosity (η₀) on the weight-average molecular weight allows for a reliable estimation of η₀ of LCB component in PP. Logarithmic mixing rule has been applied to obtain LCB molar fraction in each LCB-containing PP system. A quantitative assessment on how the LCB molar fraction influences PP rheological behavior is proposed.

中文翻译：

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聚丙烯中长链支化摩尔分数的定量

提出了一种新的方法来量化聚丙烯（PP）系统中的长链支化（LCB）摩尔分数。凝胶渗透色谱法和小振幅振荡剪切被用来量化LCB摩尔分数及其对PP流变学的影响。在挤出过程中引入越来越多的偶联剂会导致在所研究的PP模型中形成一定比例的LCB摩尔分数。零剪切粘度的依赖性（η ₀的重均分子量）允许η的可靠估计₀在PP LCB组分。对数混合规则已应用于在每个包含LCB的PP系统中获得LCB摩尔分数。提出了关于LCB摩尔分数如何影响PP流变行为的定量评估。