Rheology and thermal properties of polypropylene modified by reactive extrusion with dicumyl peroxide and trimethylol propane triacrylate
Rheology and thermal properties of polypropylene modified by reactive extrusion with dicumyl peroxide and trimethylol propane triacrylate
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DOI：
10.1002/adv.20146
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发表时间：
2009-03
影响因子：
3.1
通讯作者：
Fenghua Su;Hanxiong Huang
中科院分区：
文献类型：
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作者：
Fenghua Su;Hanxiong Huang
在双螺杆挤出机中，用三丙烯酸三甲基丙烷（TMPTA）和过氧化二氨基（DCP）对聚丙烯（PP）进行反应挤出改性。比较评价了TMPTA浓度对振荡剪切流变性能、熔体拉伸流变性能和热性能的影响。傅里叶红外光谱分析表明，接枝反应发生，TMPTA接枝到PP骨架上。差示扫描量热结果表明，改性聚苯醚的结晶温度高于初始聚苯醚和降解聚苯醚。在低频率下较高的存储模量（G′），剪切变薄程度增加，tan δ -ω图呈平稳状态，Cole-Cole图在高粘度下呈上升趋势，这些流变特性证明了长链分支被添加到线性PP分子中。熔体伸长流变学研究表明，改性PPs在TMPTA和DCP的作用下，熔体强度提高，伸长粘度增加，进一步证实了其骨架中存在长链分支（LCB）。根据振荡剪切流变学和拉伸流变学的分析结果，可以推断改性样品中的LCB水平随着TMPTA浓度的增加而增加。©2009 Wiley期刊公司科学通报，2009；在线发表于Wiley InterScience （www.interscience.wiley.com）。DOI 10.1002 / adv.20146
Trimethylol propane triacrylate (TMPTA) and dicumyl peroxide (DCP) were used to modify polypropylene (PP) by reactive extrusion in a twin-screw extruder. The effects of TMPTA concentration on oscillatory shear rheology, melt elongational rheology, and thermal properties were comparatively evaluated. Fourier transform infrared spectroscopy indicated that the grafting reaction took place and TMPTA had been grafted onto the PP backbone. Differential scanning calorimetric results showed that the crystallization temperatures of modified PPs were higher than those of the initial and degraded PPs. The rheological characteristics such as higher storage modulus (G′) at low frequency, increased degree of shear thinning, a plateau in tan δ–ω plot, and upturning at high viscosity in the Cole–Cole plots proved that the long-chain branches have been added to the linear PP molecule. The melt elongational rheology showed that the modified PPs exhibit improved melt strength and increased elongational viscosity in the presence of TMPTA and DCP, which further confirmed the existence of long-chain branching (LCB) in their backbone. According to the analytical results from oscillatory shear rheology and elongational rheology, it can be inferred that the LCB level in modified samples increases with an increase in TMPTA concentration. © 2009 Wiley Periodicals, Inc. Adv Polym Techn 28:16–25, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20146