Multiwalled carbon nanotubes grafted with polyhedral oligomeric silsesquioxane and its dispersion in poly(L-lactide) matrix
Multiwalled carbon nanotubes grafted with polyhedral oligomeric silsesquioxane and its dispersion in poly(L-lactide) matrix
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DOI：
10.1016/j.polymer.2008.01.014
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发表时间：
2008-02-18
期刊：
影响因子：
4.6
通讯作者：
Shimizu, Hiroshi
中科院分区：
文献类型：
--
作者：
Chen, Guang-Xin;Shimizu, Hiroshi
多壁碳纳米管（MWNTs）通过酰胺键被多面体低聚硅氧烷（POSS）功能化。将氧化后的MWNT （MWNT- cooh）用亚硫酰氯（SOCl2）处理后转化为酰基氯功能化MWNT (MWNT- coci)，再与氨基丙基异辛基poss反应，制得氨基丙基异辛基多面体低聚硅氧烷修饰MWNT （MWNT-g- poss）。能量滤波TEM、FTIR和拉曼光谱分析表明，POSS与MWNT共价结合，并通过热重分析（TGA）确定了官能化引起的重量增加。采用简单溶剂铸造法首次制备了不同MWNT负载的PLLA/MWNT和PLLA/MWNT-g- poss复合材料。SEM观察到MWNT-g-POSS在PLLA基体中的分散。利用自行研制的高剪切挤出机，在不同剪切速度下进行熔体复合制备复合材料。该挤出机采用了一种特殊的反馈式螺杆，实现了高剪切场。采用这种新技术，在较高转速下（>= 1500 rpm），整齐mwnt在PLLA基体中分散均匀，而在较低转速下（< 1500 rpm），分散较差。在螺杆转速范围内观察到mwnt在PLLA/MWNT-g-POSS复合材料中的均匀分散，没有任何聚集。复合材料的断裂表面不仅表现出MWNTs的均匀分散，而且与基体具有很强的界面附着力，这表明在没有与基体脱粘的情况下，MWNTs在基体中存在流状破碎但强烈嵌入的MWNTs。MWNTs的加入改善了材料的力学性能。(C) 2008 Elsevier Ltd版权所有。
Multiwalled carbon nanotubes (MWNTs) were functionalized with polyhedral oligomeric silsesquioxane (POSS) via amide linkages. The oxidized MWNT (MWNT-COOH) was converted to the acyl chloride-functionalized MWNT (MWNT-COCI) by treating them with thionyl chloride (SOCl2), and then MWNT-COCI was reacted with aminopropylisooctyl-POSS to prepare aminopropylisooctyl polyhedral oligomeric silsesquioxane modified MWNT (MWNT-g-POSS). Energy-filtering TEM, FTIR, and Raman spectroscopy revealed that the POSS was covalently attached to the MWNT and the weight gain due to the functionalization was determined by the thermogravimetric analyses (TGA). PLLA/MWNT and PLLA/MWNT-g-POSS composites with different MWNT loadings were first prepared by the simple solvent casting approach. A fine dispersion of MWNT-g-POSS throughout PLLA matrix was observed by SEM. Moreover, the composites were also prepared by using melt compounding under the different shearing speed of extruder via our custom-built high-shear extruder. A special feedback-type screw was used in this extruder to realize a high shearing How field. Using this new technique, a uniform dispersion of the neat MWNTs in the PLLA matrix was found under higher screw rotation speed (>= 1500 rpm) while poor dispersion was observed under low speed (< 1500 rpm). The homogeneous dispersion of MWNTs throughout the PLLA/MWNT-g-POSS composites Without any aggregation was observed at full range of screw rotation speed. The fractured surface of the composites showed not only a Uniform dispersion of MWNTs but also a strong interfacial adhesion with the matrix, as evidenced by the presence of runny broken but strongly embedded MWNTs in the matrix in the absence of debonding of MWNTs from the matrix. Incorporation of MWNTs improved the mechanical properties. (C) 2008 Elsevier Ltd. All rights reserved.