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Improving melt strength of polypropylene by minimal branching and blending
Journal of Applied Polymer Science ( IF 2.7 ) Pub Date : 2019-12-20 , DOI: 10.1002/app.48845
Jorge Guapacha 1, 2 , Jonathan Barbosa 2 , Enrique M. Vallés 1, 2 , Lidia M. Quinzani 1, 2 , Marcelo D. Failla 1, 3
Affiliation  

Branched polypropylenes (PPb) with markedly improved melt strength were produced without significantly affecting the processability of the original PP. A two‐step process of functionalization with MA and crosslinking with m‐XDA was used, both by batch mixing and by extrusion. Branching degrees of ~0.06 LCB/1000 monomer units or smaller were obtained. All PPbs display clear and significant strain hardening, being the PPb obtained by extrusion the one that shows the largest melt strength. This polymer has a zero‐shear‐rate viscosity slightly smaller than that of PP while its strain‐hardening index is about 10 times higher. Moreover, the nonlinear behavior of PP at elongation begins at a time similar to its terminal relaxation time or larger, while the ratio of these times reduces significantly with branching. PP/PPb blends were prepared to extend the range of obtainable melt strength in PP. They display rheological behavior between those of the mixed polymers with slight positive deviation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48845.

中文翻译:

通过最少的支化和共混提高聚丙烯的熔体强度

制备了具有显着改善的熔体强度的支化聚丙烯(PPb),而没有显着影响原始PP的可加工性。通过分批混合和挤出,使用了MA官能化和m-XDA交联的两步过程。获得〜0.06 LCB / 1000单体单元或更小的支化度。所有PPb都显示出清晰而显着的应变硬化,这是通过挤出获得的PPb表现出最大的熔体强度。该聚合物的零剪切速率粘度略小于PP,而其应变硬化指数则高约10倍。而且,PP在伸长时的非线性行为始于与其末端弛豫时间相似或更长的时间,而这些时间的比例随着分支的增加而显着降低。制备PP / PPb共混物以扩展PP中可获得的熔体强度范围。它们在混合聚合物之间表现出流变行为,并具有轻微的正偏差。分级为4 +©2019 Wiley Periodicals,Inc.J.Appl。Polym。科学2019137,48845。
更新日期:2020-03-27
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