无机填料改性聚丙烯结晶性能的研究进展

聚丙烯经无机填料填充改性后,其结晶性能得到改善。本文综述了近年来无机填料改性聚丙烯结晶性能的研究进展,重点讨论了碳酸钙、金属氧化物、高岭土、纤维类、蒙脱土、碳纳米管、二氧化硅等无机填料在聚丙烯结晶性能改性中的应用,并对无机填料改性聚丙烯结晶性能发展趋势及应用前景作了展望。     

碳纳米管对PP/SPTW复合材料力学性能的影响

目的研究不同含量的多壁碳纳米管(CNT)对聚丙烯/六钛酸钾晶须复合材料力学性能的影响。方法将经表面改性处理的多壁碳纳米管与改性过的六钛酸钾晶须、聚丙烯(PP)、马来酸酐接枝聚丙烯(PP-g-MAH),采用熔融共混法,利用双辊开炼机熔融共混制得PP/PP-g-MAH/SPTW/碳纳米管复合材料。比较不同含量的改性多壁碳纳米管对PP/PP-g-MAH/SPTW复合材料力学性能的影响。结果多壁碳纳米管表面经过混酸处理后,在复合材料中分散均匀,与聚合物基体界面间结合良好,对复合材料起到增韧增强作用,但是当碳纳米管质量分数较大时,开始出现团聚现象,反而使复合材料的力学性能降低。结论当碳纳米的质量分数为0.5%左右时,复合材料力学性能最佳。     

碳纳米管/三嵌段聚合物(PPP)无溶剂流体的制备及对聚丙烯性能的影响

采用三嵌段聚合物(PPP)对酸化碳纳米管(MWNTs-COOH)进行改性,制备MWNTs-COOH/PPP无溶剂流体。采用流变仪研究其流变性能,采用差热扫描(DSC)研究不同制备方法对MWNTs-COOH/PPP/聚丙烯复合材料性能的影响。结果表明,无溶剂存在时,MWNTs-COOH/PPP复合物具有液体的特征,碳纳米管含量为27.37%。以MWNTs-COOH/PPP复合物作为增强材料,采用溶液法和机械法制备聚丙烯纳米复合材料,碳纳米管可以使聚丙烯的结晶度有一定程度提高。     

原位聚合聚苯氨包覆碳纳米管的研究

进行了用苯氨单体在含有分散碳纳米管的环境中发生聚合,使聚苯胺包覆碳纳米管,然后把这些碳纳米管添加到聚丙烯中的实验.利用透射电子显微镜,X射线衍射仪对碳纳米管的分散效果,碳纳米管/聚苯胺界面进行了分析,检测.对加有碳纳米管/聚苯胺的聚丙烯进行了抗拉强度测试,并对试样弯曲断裂断口进行了扫描电镜分析和EDS分析.结果表明苯胺可以很好地在碳纳米管上形核聚合,形成的聚苯胺能够完全包覆和缠绕在碳纳米管上,从而有利于碳纳米管处于很好的分散状态.包覆有聚苯胺的碳纳米管添加到聚丙烯中提高了聚苯烯的力学性能,与不添加填料的聚苯烯相比,在相同实验条件下添有包覆聚苯氨的碳纳米管2%的聚苯烯常温拉伸强度提高了70%.     

溶液法制备聚丙烯/碳纳米管复合材料的结晶行为

采用溶液法制备了聚丙烯/碳纳米管复合材料,并通过光学显微镜、DSC、TGA对复合材料的结晶行为进行了研究。研究发现,碳纳米管具有异相成核的作用,加入了碳纳米管的聚丙烯晶粒明显细化,且复合材料的热稳定性、阻燃性能得到了明显提高。     

巯基改性碳纳米管的制备与表征

采用一种新颖、高效的方法,将元素硫应用于碳纳米管(CNTs)的表面改性,在CNTs表面通过硫自由基加成随后还原的方法接枝巯基基团,这种改性方法步骤简单、安全,且不会破坏CNTs的内部结构,可以应用于更多领域。利用该方法分别对多壁碳纳米管和单壁碳纳米管进行表面改性,制备了巯基改性碳纳米管,确定了巯基改性多壁碳纳米管的最佳反应条件并采用傅里叶变换红外光谱仪、拉曼光谱仪、热重分析仪和X射线光电子能谱对所制样品进行表征。     

碳纳米管/马来酸酐接枝聚丙烯复合材料制备及性能研究

本文采用溶液混合的方法制备了碳纳米管/马来酸酐接枝聚丙烯复合材料.光学显微镜照片显示,碳纳米管的加入使聚丙烯晶粒细化,同时晶粒大小比较均一.材料SEM和TEM像表明,当碳纳米管含量为5wt%时,碳纳米管在聚丙烯基体中仍分散较好,没有明显的团聚现象.拉伸实验结果显示当碳纳米管含量为3%时,拉伸强度可提高50%.     

全氟辛基季胺碘化物改性碳纳米管对天然橡胶胶乳性能的影响

用水溶性的阳离子表面活性剂全氟辛基季胺碘化物FC-134对碳纳米管进行非共价键改性,并用液相法制备改性碳纳米管/天然橡胶复合材料,研究了改性碳纳米管对天然橡胶复合材料的影响。结果表明,改性碳纳米管在水介质中具有很好的稳定性。佩恩效应表明,碳纳米管经过表面修饰增强了与橡胶的相互作用,降低了碳纳米管之间的相互作用。橡胶加工分析仪的结果表明,碳纳米管均匀地分散到复合材料中。与未改性碳纳米管/天然橡胶胶乳复合材料相比,改性碳纳米管/天然橡胶胶乳复合材料硫化胶的撕裂强度提高了65%,拉伸强度提高了29%。     

多壁碳纳米管对聚丙烯韧性和阻燃的影响

通过添加表面活性剂和两步法的加工工艺,研究了未进行任何预处理的多壁碳纳米管对聚丙烯力学性能、阻燃性能和电性能的影响。结果显示,聚丙烯/多壁碳纳米管复合材料在具有一定抗静电能力的同时,其缺口冲击强度可达47.3 k J/m2,相对于纯的聚丙烯提高了414%。在聚丙烯溴系阻燃体系中,多壁碳纳米管比超导炭黑更适合作为导电填料,在燃烧时能抑制火焰和滴落物的产生,并能有效缩短续焰时间t1和t2,最终使复合材料具备抗静电性能,且达到V-0阻燃级别。     

多壁碳纳米管的酰氯化和氨化改性及其结构表征

分别以氯化亚砜和乙二胺为改性试剂对多壁碳纳米管进行化学改性,通过红外光谱、扫描电子显微镜、热重分析和X射线衍射对制备的碳纳米管进行表征。结果表明,改性碳纳米管中含有酰氯基团和氨基基团,同时,改性使碳管长度变短,反应活性增加,但其特殊结构未受破坏。     

Mechanical strength improvement of polypropylene threads modified by PVA/CNT composite coatings

Poly (vinyl alcohol)/carbon nanotube (PVA/CNT) composite was coated on the surface of polypropylene thread for toughness enhancement. Multiwall carbon nanotubes (MWNTs) were treated in acid and alkali to get water-soluble nanotubes, and then embedded into poly (vinyl alcohol) (PVA) matrix, resulting in polymer-carbon composite with homogeneous nanotube dispersion. The stress-strain measurements show that the tensile strength and toughness of the PVA/CNT coated thread increased by 117% and 560%, respectively. These results are supportive of good interfacial bonding between the carbon nanotubes (CNTs) and polymer matrix.     

The influence of carbon nanotube functionalization route on the efficiency of dispersion in polypropylene by twin-screw extrusion

The joint effect of chemical functionalization and polymer melt blending conditions on carbon nanotube dispersion in polypropylene, as well as its influence on the electrical and mechanical properties of the resulting composites were investigated. Melt blending was performed using a prototype twin screw extruder enabling sampling along the barrel. The carbon nanotube dispersion was assessed by optical and scanning electron microscopy. The functionalization reaction was tailored for compatibility with the polymer, and characterized by X-ray photoelectron spectroscopy. In particular, nanotubes covalently bonded to polypropylene showed distinctive dispersion ability, while the carbon nanotube dispersion remained stable even after re-melting. However, the polypropylene-functionalized nanotubes produced composites with higher electrical resistivity, possibly due to the insulating effect of the polymer bonded to the nanotubes surface.     

Multiwalled carbon nanotube reinforced polymer composites

Due to their high stiffness and strength, as well as their electrical conductivity, carbon nanotubes are under intense investigation as fillers in polymer matrix composites. The nature of the carbon nanotube/polymer bonding and the curvature of the carbon nanotubes within the polymer have arisen as particular factors in the efficacy of the carbon nanotubes to actually provide any enhanced stiffness or strength to the composite. Here the effects of carbon nanotube curvature and interface interaction with the matrix on the composite stiffness are investigated using micromechanical analysis. In particular, the effects of poor bonding and thus poor shear lag load transfer to the carbon nanotubes are studied. In the case of poor bonding, carbon nanotubes waviness is shown to enhance the composite stiffness.     

碳纳米管的加入对PMMA强度和导电性能的影响

本文研究了ＰＭＭＡ与碳纳米管的原位复合过程、复合体强度及电学性能，结果表明，碳纳米管与ＰＭＭＡ原位复合时，将参与ＭＭＡ的链式聚合反应，这不仅影响了ＭＭＡ的聚合过程和复合体的强度，而且影响了碳纳米管在基体ＰＭＭＡ中的分散度。适当推迟碳纳米管的加入时间，将提高ＰＭＭＡ的强度，碳纳米管的加入也将提高ＰＭＭＡ的导电性能。     

PA6／碳纳米管复合材料的复合方法的研究

ＣＶＤ法生产的碳纳米管经处理后呈纳米级分散，且表面产生大量的－ＯＨ官能团。碳纳米管与ＰＡ６（尼龙６）复合时，将通过其表面的－ＯＨ参加ＰＡ６的聚合反应，并阻碍ＰＡ６分子链的长大，削弱基体的强度。选择适当的复合方法，在尽量减少碳纳米管对ＰＡ６分子长大阻碍的基础上，改善碳纳米管在基体ＰＡ６中的分散，并进行后处理，可获得机能性能较好的ＰＡ６／碳纳米管复合材料。     

A strategy for improving mechanical properties of a fiber reinforced epoxy composite using functionalized carbon nanotubes

Carbon fiber reinforced epoxy composite laminates are studied for improvements in quasi static strength and stiffness and tension-tension fatigue cycling at stress-ratio (R-ratio) = +0.1 through strategically incorporating amine functionalized single wall carbon nanotubes (a-SWCNTs) at the fiber/fabric-matrix interfaces over the laminate cross-section. In a comparison to composite laminate material without carbon nanotube reinforcements there are modest improvements in the mechanical properties of strength and stiffness; but, a potentially significant increase is demonstrated for the long-term fatigue life of these functionalized nanotube reinforced composite materials. These results are compared with previous research on the cyclic life of this carbon fiber epoxy composite laminate system reinforced similarly with side wall fluorine functionalized industrial grade carbon nanotubes. Optical and scanning electron microscopy and Raman spectrometry are used to confirm the effectiveness of this strategy for the improvements in strength, stiffness and fatigue life of composite laminate materials using functionalized carbon nanotubes.     

Continuous carbon nanotube reinforced composites

Carbon nanotubes are considered short fibers, and polymer composites with nanotube fillers are always analogues of random, short fiber composites. The real structural carbon fiber composites, on the other hand, always contain carbon fiber reinforcements where fibers run continuously through the composite matrix. With the recent optimization in aligned nanotube growth, samples of nanotubes in macroscopic lengths have become available, and this allows the creation of composites that are similar to the continuous fiber composites with individual nanotubes running continuously through the composite body. This allows the proper utilization of the extreme high modulus and strength predicted for nanotubes in structural composites. Here, we fabricate such continuous nanotube polymer composites with continuous nanotube reinforcements and report that under compressive loadings, the nanotube composites can generate more than an order of magnitude improvement in the longitudinal modulus (up to 3,300%) as well as damping capability (up to 2,100%). It is also observed that composites with a random distribution of nanotubes of same length and similar filler fraction provide three times less effective reinforcement in composites.     

基于碳纳米管的三维编织复合材料健康监测技术

分析了三维编织复合材料试件结构健康监测技术现状,结合三维编织复合材料编织工艺,提出了碳纳米管在三维编织复合材料试件健康监测方面的应用方法。结果说明碳纳米管应用于三维编织复合材料整体结构监测是可行的。碳纳米管传感器在三维编织复合材料试件结构健康监测中具有优异的应变传感特性,且嵌入的碳纳米管传感器对复合材料的力学性能影响不大。这为内置碳纳米管传感器应用于复合材料制件的健康检测提供了一种新的综合和分布式技术,为先进智能复合材料的研发与应用提供了依据。     

碳化硅颗粒填充的碳纳米管/环氧树脂复合材料的吸波性能

以碳纳米管、碳化硅颗粒为原料制备环氧树脂复合吸波材料,并对其吸波性能进行测试,研究了碳纳米管、碳化硅颗粒含量与复合材料吸波性能的关系.结果表明碳纳米管、碳化硅颗粒的含量对复合材料的吸波性能有较大影响.随碳纳米管含量的增加,碳纳米管/环氧树脂复合材料的吸波性能先提高后降低,碳纳米管含量存在最佳值(12%,质量分数).将碳...