Perez Hector Sebastian, Román Allen Jonathan, Bechara Senior Abrahán, Osswald Tim
Polymer Engineering Center (PEC), University of Wisconsin-Madison, 1513 University Ave, Madison, WI 53706, USA.
Polymers (Basel). 2023 Jun 23;15(13):2790. doi: 10.3390/polym15132790.
Understanding the mechanics of fiber attrition during the extrusion process is highly important in predicting the strength of long fiber-reinforced thermoplastic composites. However, little work has been done to investigate the mechanics of fiber dispersion and its effects on fiber attrition. This study aims at investigating fiber dispersion in simple shear flows for long fiber-reinforced thermoplastic pellets. Depending on the fabrication process, fiber bundles display distinct levels of compaction within the pellets. Studies have shown that morphological differences can lead to differences in dispersion mechanics; therefore, using a Couette rheometer and a sliding plate rheometer, coated and pultruded pellets were subjected to simple shear deformation, and the amount of dispersion was quantified. Additionally, a new image-based analysis method is presented in this study to measure fiber dispersion for a multi-pellet-filled system. Results from the single-pellet dispersion study showed a small amount of correlation between the dimensionless morphological parameter and the dispersion measurement. Pultruded and coated pellets were both found to have similar dispersion rates in a multi-pellet system. However, pultruded pellets were found to have a higher dispersion value at all levels when compared with coated pellets in both dispersion studies.
了解挤出过程中纤维磨损的机理对于预测长纤维增强热塑性复合材料的强度非常重要。然而，在研究纤维分散机理及其对纤维磨损的影响方面，所做的工作很少。本研究旨在研究长纤维增强热塑性粒料在简单剪切流中的纤维分散情况。根据制造工艺的不同，纤维束在粒料中表现出不同程度的压实。研究表明，形态差异会导致分散机理的差异；因此，使用库埃特流变仪和滑板流变仪，对涂层粒料和拉挤粒料进行简单剪切变形，并对分散量进行量化。此外，本研究还提出了一种新的基于图像的分析方法，用于测量多粒料填充系统中的纤维分散情况。单粒料分散研究的结果表明，无量纲形态参数与分散测量之间存在少量相关性。在多粒料系统中，拉挤粒料和涂层粒料的分散速率相似。然而，在两项分散研究中，与涂层粒料相比，拉挤粒料在所有水平上的分散值都更高。
