The melt grafting preparation and rheological characterization of long chain branching polypropylene
The melt grafting preparation and rheological characterization of long chain branching polypropylene
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DOI：
10.1016/j.polymer.2009.10.006
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发表时间：
2009-11-27
期刊：
影响因子：
4.6
通讯作者：
Zheng, Anna
中科院分区：
文献类型：
--
作者：
Li, Shuzhao;Xiao, Miaomiao;Zheng, Anna
为了研究长链支化聚丙烯（PP）的神学性能，在新型扩链剂聚己二胺-盐酸胍（PHGH）的存在下，通过熔融接枝反应将长链支化聚丙烯（LCB）接枝到线性PP上。通过瞬态转矩曲线和红外光谱分析证实了功能化聚丙烯与PHGH之间的分支反应。通过差示扫描量热法（DSC）和偏光显微镜测量，进一步证实了长链分支结构的存在。此外，为了区分LCB PP和线性PP，研究了LCB PP和线性PP在剪切流动下的粘弹性特性。结果发现，LCB PP在低频时的弹性响应比线性PP明显增强，这意味着LCB PP存在线性PP所没有的长松弛时间模式。此外，LCB PP的分支水平使用详细的方法进行了量化。这与接枝PHGH在PP上的摩尔量相对应。(C) 2009 Elsevier Ltd.。版权所有。
To study the theological properties of long chain branching (LCB) polypropylene (PP), long chain branches (LCB) were grafted onto the linear PP by melt grafting reaction in the presence of a novel chain extender, poly(hexamethylendiamine-guanidine hydrochloride) (PHGH). The branching reactions between the functionalized PP and PHGH were confirmed by transient torque curves and FTIR. By differential scanning calorimetry (DSC) and polarized microscope measurements, the presence of long chain branching structures was further confirmed. Also, the viscoelastic properties of the LCB PP and linear PP under shear flow were investigated for distinguishing LCB PP from linear PP. It was found that the elastic response of LCB PP at low frequencies was significantly enhanced in comparison with that of the linear PP, implying a presence of a long relaxation time mode that was not revealed in linear PP. Moreover, the branching levels of LCB PP were quantified using a detailed method, which was in correspondence with the molar amount of PHGH grafted on PP. (C) 2009 Elsevier Ltd. All rights reserved.