A Study on Polyurethane Hybrid Nanocomposite Foams Reinforced with Multiwalled Carbon Nanotubes and Silica Nanoparticles

Multifunctional polyurethane foams reinforced with multiwalled carbon nanotubes and silica nanoparticles enhanced specific properties. We studied the effects of nanoparticle addition into polyurethane on mechanical properties and thermal stability by means of tensile, Charpy impact, hardness tests, and thermogravimetric analysis. Nanoparticles added to polyurethane are multiwalled carbon nanotubes, two types of silica nanoparticles, and multiwalled carbon nanotube/spherical silica as hybrid filler. Hybrid polyurethane/spherical silica/multiwalled carbon nanotube nanocomposite with the constant overall content of 0.75?wt% showed higher tensile strength, hardness, and thermal stability than either of nanoparticles at this content, which approves a synergistic effect between multiwalled carbon nanotubes and silica nanoparticles.     

In situ Preparation of Polyimide Composites Based on Functionalized Carbon Nanotubes

Three series of composite films based on polyimide and MWNTs were prepared by conversion of pyromellitic dianhydride and 4,4′‐oxydianiline in the presence of the nanotubes, followed by thermal imidization. Carboxy‐ and amino‐functionalized as well as unmodified nanotubes were used. It was demonstrated that just 0.5 wt.‐% of nanotubes increased the tensile properties of the composite films distinctly. Surprisingly, a significant influence of the functional groups on the mechanical performance of the composite films could not be demonstrated. However, it was shown that functional groups may reduce the conductivity of the films. Furthermore, the influence of ultrasonication is discussed.

     

环氧树脂/碳纳米管导热复合材料的制备与性能研究

采用先酸化再空气氧化的方法对碳纳米管（CNTs）进行了纯化处理,并制备了2种环氧树脂(EP)/CNTs导热复合材料。研究了不同含量的CNTs及纯化CNTs对复合材料的导热性能、冲击性能及弯曲性能的影响。结果表明,纯化处理后,CNTs表面的催化剂粒子和无定形碳被去除,得到了纯净CNTs;当纯化CNTs含量为1.5 %时(质量分数,下同),材料的冲击强度和弯曲强度最高,分别为24.95 kJ/m2、127.2 MPa;当纯化CNTs含量为1.5 %时,复合材料的热导率可达1.237 W/（m·℃）。     

酸化处理对碳纳米管改性聚氨酯性能的影响

近年来,碳纳米管以其优异的性能引起了极大的关注,从而广泛用于改性聚合物材料。采用浓硫酸和浓硝酸的混合酸对多壁碳纳米管进行酸化处理,并采用原位聚合法制备了碳纳米管改性聚氨酯材料,研究了碳纳米管的酸化处理对材料力学性能和热稳定性的影响。结果表明,碳纳米管的加入使得聚氨酯材料的拉伸强度和弹性模量升高,断裂伸长率减小,提高了聚氨酯材料的热稳定性,而且经过酸化的碳纳米管对聚氨酯材料的改性要比未酸化碳纳米管对聚氨酯材料的改性效果更为显著。     

碳纳米管的制备

综述了碳纳米管的几种制备工艺和相关的生长机制,还介绍了近两年来碳纳米管制备的进展情况,包括新型制备技术、特殊结构的碳纳米管制备。     

聚苯胺接枝多壁碳纳米管的制备及热电性能

通过原位聚合,将聚苯胺接枝到多壁碳纳米管的表面,制备了聚苯胺/碳纳米管纳米纤维。聚苯胺均匀地包覆在碳纳米管表面,当苯胺与碳纳米管投料比为1∶1时,包覆层厚度约为15 nm。聚苯胺/多壁碳纳米管的电导率和塞贝克系数随温度升高而增大,且增大碳纳米管含量同时提高了复合材料的电导率和塞贝克系数,改善了功率因子。     

碳纳米管增强聚合物复合材料研究进展

综述了碳纳米管增强聚合物复合材料研究进展,介绍了碳纳米管的力学性能、碳纳米管增强聚合物的制备方法,阐述了近年来原位聚合、电纺丝、层层自组装等方法在这类复合材料制备中的应用。     

碳纳米管补强丁腈橡胶的性能研究

研究碳纳米管用量对丁腈橡胶(NBR)性能的影响。结果表明:随着碳纳米管用量的增大,胶料的最小和最大转矩增大,焦烧时间和正硫化时间缩短;硫化胶的100%和300%定伸应力增大,拉伸强度和撕裂强度先增大后减小,高温拉伸性能保持率总体增大,耐热和耐磨性能提高;加入6份碳纳米管,硫化胶的储能模量在温度较低时减小,损耗因子峰值减小。扫描电镜分析显示,碳纳米管在NBR中整体分散均匀,局部存在团聚现象。     

碳纳米管的制备研究

本文介绍了国内外碳纳米管(CNTS)最新研究进展，分析了制备碳纳米管所必需的3个关键条件：碳源、催化剂、能源；并分别研究了它们对碳纳米管生长的影响。通过碳纳米管的生长机理探讨了大规模制备碳纳米管的可行性。     

聚合物/CNTs复合材料制备及其力学性能影响因素

综述了近年CNTs增强聚合物复合材料的制备方法,重点分析了制备过程中影响复合材料力学性能的主要因素,总结了聚合物/CNTs复合材料制备过程中存在的技术难题并对其未来的发展应用进行了展望。     

碳纳米管制备方法的研究进展

碳纳米管具有独特的一维纳米结构,具有极大的比表而积及其优异的物理化学性能,在纳米电子器件、储氢材料、传感器等领域有着巨大的应用前景。文章综述了碳纳米管几种主要的制备方法,如电弧放电法、化学气相沉积法、激光蒸发法、模版法等,通过介绍最新的制备方法和进展,为研究人员提供进一步的参考价值。     

Superior Mechanical Properties of Double-Network Hydrogels Reinforced by Carbon Nanotubes without Organic Modification

A facile method is developed to fabricate nanocomposite double-network (DN) gels with excellent mechanical properties, which do not fracture upon loading up to 78 MPa and a strain above 0.98, by compositing of carbon nanotubes (CNTs) without organic modification. Investigations of swelling behaviors, and compressive and tensile properties indicate that equilibrium swelling ratio, compressive modulus and stress, fracture stress, Young’s modulus, and yield stress are significantly improved in the presence of CNTs. Scanning electron microscopy (SEM) reveals that the pore size of nanocomposite DN gels is decreased and some embedded micro-network structures are observed on the fracture surface in comparison to DN gels without CNTs, which leads to the enhancement of mechanical properties. The compressive loading-unloading behaviors show that the area of hysteresis loop, dissipated energy, for the first compressive cycle, increases with addition of CNTs, which is much higher than that for the successive cycles. Furthermore, the energy dissipation mechanism, similar to the Mullins effect observed in filled rubbers, is demonstrated for better understanding the nanocomposite DN polymer gels with CNTs.     

Multiwalled Carbon Nanotubes/Hectorite Hybrid Reinforced Styrene Butadiene Rubber Nanocomposite: Preparation and Properties

Clay-assisted dispersion of MWCNT has emerged as a novel alternative to its conventional modification. The report deals with preparation of MWCNT/hectorite hybrid (HMH) by dry grinding method and its utilization for the reinforcement of styrene butadiene rubber (SBR). Significant improvement in tensile strength (210%) and elongation at break (42%) of SBR/HMH nanocomposite at 0.7 wt.% HMH shows its superior reinforcing efficiency. Comparison with individual fillers confirms significant synergy. Best thermal stability and dielectric response are achieved at 0.3 and 0.7 wt.% filler contents respectively. Improved properties of the nanocomposites are ascribed to enhanced level of filler dispersion and polymer-filler interaction.     

碳纳米管和偶联剂协同作用对热塑性复合材料力学性能的影响

将碳纳米管（CNTs）和硅烷偶联剂（AMEO）分散至纤维表面,制备聚芳硫醚（PAS）/玻璃纤维布/CNTs/AMEO复合材料,并探究复合材料的表面形貌和力学性能。结果表明：未经偶联剂处理的体系中,CNTs与纤维的结合性较弱。将CNTs进行羧化和偶联剂处理,能够提高CNTs和纤维之间的结合强度,提升纤维与PAS之间的应力传递,进一步提高复合材料的力学性能。当AMEO加入量为400、800、1 200、1 600μL/gCNTs,复合材料的拉伸强度分别为352、381、403、390 MPa,弯曲强度分别为380、414、443、478 MPa。由此得出,CNTs和AMEO协同作用明显提高复合材料的力学性能。     

碳纤维增强聚氨酯弹性体复合材料的研究

为了制备具有优良导热性能、耐热性能和力学性能的新型聚氨酯(PUR)弹性体复合材料,采用预聚体法以聚四氢呋喃醚二醇(PTMG),2,4-甲苯二异氰酸酯(TDI)和碳纤维(CF)粉末为原料,制备了不同CF含量的CF增强PUR弹性体复合材料。对其进行了导热性能、耐热性能和力学性能测试,并通过扫描电子显微镜考察了CF在PUR基体中的分散状态。红外测试结果表明,CF表面含有可以与PUR基体发生反应的—OH和—COOH。当CF质量分数为0.3%时,CF可以均匀地分散在PUR基体中,CF增强PUR弹性体复合材料的拉伸强度、撕裂强度、100%和300%定伸强度、玻璃化转变温度和热导率分别为42.24 MPa,94.03 k N/m,9.33 MPa,24.87 MPa,96.7℃和0.138 5 W/(m·K),比纯PUR弹性体分别提高了27.8%,32.2%,76.4%,102.2%,18.5℃和26.4%,而断裂伸长率为367.62%,仅下降19.5%。     

短切碳纤维增强聚酰亚胺泡沫的制备及性能

针对现有软质聚酰亚胺泡沫强度低的缺点,通过一步法制备了短切碳纤维增强聚酰亚胺泡沫,研究了短切碳纤维的添加量对聚酰亚胺泡沫的化学结构、微观形貌、压缩强度及热导率的影响。结果表明,短切碳纤维在发泡过程中起到成核剂的作用,随着其添加量的增加,泡沫的泡孔平均尺寸先减小后增加;当短切碳纤维质量分数为20%时,泡孔的最小平均尺寸为507μm;泡沫密度随着短切碳纤维用量的变化没有明显的改变;泡沫的压缩强度随着短切碳纤维的用量先增大后逐渐减小,压缩强度最大为54.52 kPa;短切碳纤维的加入对聚酰亚胺泡沫材料的化学结构和热稳定性没有明显的影响,但是材料的热导率随着短切碳纤维含量的增加有一定的增加。     

改性碳纳米管对三元乙丙橡胶导热性能和物理性能的影响

将未改性及酚醛树脂包覆改性碳纳米管填充到三元乙丙橡胶(EPDM)中,观察改性前后碳纳米管在橡胶基体中的分散情况,并研究碳纳米管/EPDM复合材料的热导率和物理性能。结果表明:经酚醛树脂包覆改性后,碳纳米管在橡胶基体中分散良好,复合材料的热导率和物理性能均有一定程度的提高;当碳纳米管与酚醛树脂用量比为1∶1时,改性碳纳米管/EPDM复合材料的热导率较高,物理性能较好。     

碳纳米管的制备

作为纳米材料典型代表之一的碳纳米管自被发现以来 ,以其独特的结构和性能引起了人们广泛的关注 ,本文简介了碳纳米管的发展和现状 ,详细阐述了碳纳米管的几种制备方法。     

碳纳米管对硅酸盐水泥力学性能的影响研究

研究了用超声分散的碳纳米管对硅酸盐水泥物理力学性能的影响,并利用XRD和SEM等测试手段对碳纳米管改性水泥的水化产物及硬化浆体的形貌进行了分析.结果表明:碳纳米管的掺入改变了水泥净浆的标准稠度用水量和凝结时间,提高了其抗压和劈裂抗拉强度,但并未造成安定性不良.随碳纳米管掺量的增加,水泥净浆的标准稠度用水量逐渐增加,凝结时间不断缩短,标养28天的抗压和疲劳抗拉强度较未掺碳纳米管的硬化浆体分别提高了15.34％和18.44％.XRD分析表明碳纳米管的掺入不仅提高了水泥净浆的水化程度,增加了C-S-H的生成量,而且降低CH的结晶度.SEM证明碳纳米管的掺入较未掺的水泥净浆硬化浆体结构趋于优化,更致密.     

Thermoplastic Soy Protein Nanocomposites Reinforced by Carbon Nanotubes

MWNTs of various sizes were compounded into SPI matrix by solution mixing and then compression‐molded into nanocomposite sheets, which were characterized by XRD, SEM, TEM, and tensile and water uptake testing. The resultant nanocomposites showed improved mechanical performance and higher water resistance depending on MWNT size and content. This work details a strategy to achieve improved performance, especially in terms of mechanical properties, using MWNTs of various sizes to regulate the entanglement and penetration between SPI and MWNTs.