共查询到17条相似文献,搜索用时 46 毫秒
1.
分别采用聚羧酸减水剂、聚乙烯吡咯烷酮(PVP)、洗衣粉(XYF)等3种表面活性剂并结合超声波分散方法,研究了多壁碳纳米管(MWCNTs)在水中和水泥浆中的分散性及其对水泥强度的影响,采用人工观察和扫描电子显微镜分别评价了MWCNTs在水中的分散性和在水泥硬化体中的分布情况。结果表明:单独采用减水剂为分散剂并在超声波分散条件下,MWCNTs在水中和水泥浆中容易发生团聚,无法起到增强作用;在超声波分散作用下,采用PVP和XYF为分散剂能够显著提高MWCNTs在水中和水泥浆中的分散性,PVP大幅度提高了水泥硬化体强度,但XYF却使强度大幅度降低,这是因其具有的较强起泡功能使水泥硬化体中的气泡量增加、气孔尺寸提高,并形成一些较大孔隙,从而显著降低了水泥石的密实性。 相似文献
2.
3.
以十二烷基苯磺酸钠(SDBS)为分散剂,氯化胆碱-丙二酸类离子液体为溶剂,通过超声分散处理多壁碳纳米管,制备了分散性良好的多壁碳纳米管悬浮液。采用紫外-可见分光光度法和粒径测试考察了SDBS对多壁碳纳米管悬浮液分散性的影响。结果表明,在多壁碳纳米管悬浮液中,当SDBS的浓度为1.2 mmol?L~(-1)左右时,悬浮碳纳米管的浓度最大,约为初始浓度的89%。悬浮液中多壁碳纳米管的平均粒径随着SDBS的浓度的增大而逐渐降低,在SDBS的浓度大于1.0 mmol?L~(-1)时,下降趋势变缓慢。添加SDBS后的多壁碳纳米管悬浮液的稳定性显著提高,192 h后基本趋于稳定。 相似文献
4.
5.
多壁碳纳米管分散性研究 总被引:5,自引:1,他引:4
通过对多壁碳纳米管的改性研究,寻找提高碳纳米管分散性的途径。采用NaOH对碳纳米管进行预处理,通过SEM、DSC分析表明,该处理过程对去除多壁碳纳米管中杂质和提高其分散性有积极效果。通过H2SO4和HNO3的混酸处理法与HNO3处理法的对比,知前者对碳纳米管的损失要大于后者,且通过对FTIR的对比分析,后者对碳纳米管的改性效果好于前者。TG、TEM分析表明,聚乙烯醇均匀包覆在碳纳米管表面,碳纳米管分散性较酸处理的有所改进。 相似文献
6.
7.
采用分散剂、超声处理及离心机分离作用,得到分散均匀、稳定状态的多壁碳纳米管(MWCNTs)悬浮液和分散不均匀、团簇状态的MWCNTs沉淀,分别将这两种状态的MWCNTs掺入水泥净浆中,研究MWCNTs分散性对水泥基材料电学性能和电热特性的影响.结果表明:MWCNTs在水泥基体中分散均匀时,随MWCNTs掺量的增加试块电阻率下降;当MWCNTs在水泥基体中分散不均匀时,试块的导电性与MWCNTs掺量没有明确的相关性.MWCNTs水泥净浆的电阻率均随测试温度的升高不断降低,当温度超过80℃时,电阻率趋于恒定,并且MWCNTs分散均匀时,水泥净浆电阻率受温度影响的程度随MWCNTs掺量增高而减小;MWCNTs在基体中分散效果好时,水泥净浆因通电引起的升温速率和幅度随着MWCNTs掺量增大而提高. 相似文献
8.
9.
综述了在熔融共混制备碳纳米管(CNTs)/聚合物复合材料过程中CNTs的分散机理和分散性的影响因素。重点探讨了聚合物基体相对分子质量、螺杆转速、料筒温度、螺杆结构以及添加剂等因素对CNTs在热塑性聚合物基体中分散性的影响,最后对熔融共混分散CNTs方法进行了展望。 相似文献
10.
11.
碳纳米管的分散及表面改性 总被引:14,自引:0,他引:14
碳纳米管具有独特的结构和优异的物理化学性能,但碳管间易相互缠绕而发生团聚是限制其应用的主要原因.本文对国内外关于碳纳米管的分散及表面改性的研究进行了综合评述,评述了这些方法的优缺点,并对今后的研究方向做了展望. 相似文献
12.
碳纳米管在聚合物基体中的分散方法 总被引:2,自引:0,他引:2
综述了碳纳米管(CNTs)在聚合物基体中的分散方法,包括直接分散法和表面修饰法,其中表面修饰又根据是否形成共价键分为两类,重点叙述了近几年成为研究热点的非共价键修饰法。直接分散法简单、快捷,保证了CNTs的结构完整性,但分散效果较差;表面修饰法通过共价键或非共价键的方式对CNTs的表面进行改性,克服了直接分散法的缺点,但共价键的形成会破坏CNTs的结构完整性,造成CNTs其他性能的下降,而非共价键修饰又存在结合不牢固的问题。因此,CNTs在聚合物基体中的分散方法仍是今后聚合物/CNTs复合材料应用中需要解决的一个重点问题。 相似文献
13.
14.
Zhong-Ming Li Sha-Ni Li Xiang-Bin Xu Ai Lu 《Polymer-Plastics Technology and Engineering》2013,52(2):129-134
A two-step method was used to prepare carbon nanotube (CNT)/ethylene-vinylacetate copolymer (EVA)/polyethylene (PE) and CNT/polycarbonate (PC)/PE composites. First, CNT-EVA and CNT-PC master batches were obtained by solution-phase processing, and second, the CNT masterbatches were melt-mixed with PE. Phase morphological observation indicates that there is a marked decrease in the size of the dispersed particles in the composites. This finding is of practical significance to develop new polymer materials based on blending concept. 相似文献
15.
Hye Jin Park Hye Young Heo Seung Cheol Lee Min Park Sang-Soo Lee Junkyung Kim Ji Young Chang 《Journal of Inorganic and Organometallic Polymers and Materials》2006,16(4):359-364
A polyphosphazene polyelectrolyte was prepared as a dispersing agent of SWNTs in water. Poly(organophosphazene) was prepared
by sequential treatment of poly(dichlorophosphazene) with sodium 4-phenylphenoxide, sodium phenoxide, and sodium trifluoroethoxide
in THF. Their substitution percentages were 60, 24, and 16%, respectively. A water-soluble polyphosphazene polyelectrolyte
was obtained by sulfonation of aromatic rings by using fuming sulfuric acid. SWNTs were dispersed in an aqueous polymer solution
by sonication to give a black homogeneous dispersion. The supramolecular association between the nanotube and the sulfonated
polyphosphazene was investigated by TEM, SEM, and AFM. The SEM image of the cleaved edge of the bucky paper, obtained by filtration
of the dispersion of SWNTs, showed the nanotubes uniformly wrapped with the polymer. Their diameters were about 30 nm, suggesting
small bundles of SWNTs rather than individual SWNTs. Individual SWNTs coated with the polymer were also observed by TEM. The
total diameter of the coated tube was about 10 nm and a polymer layer thickness was lager than 4 nm.
This paper is dedicated to Professor Harry R. Allcock in recognition of his outstanding contributions to polymer chemistry
and his inspirational teaching. 相似文献
16.
A novel jet dispersion technique was developed and investigated which enabled excellent carbon nanotube (CNT) dispersion by high exfoliation at even very low pressure drops. Suitable procedures were developed for the characterization of agglomerate size and fraction of individual CNTs. The appropriate characterization enabled the definition of a dimensionless dispersing parameter and the development of a kinetic model that describes CNT dispersion in dependence of the volumetric energy input. The rheological behavior of CNT suspensions in steady-shear flows was investigated and demonstrated how the agglomerate fracture and CNT individualization influence the suspension viscosity. 相似文献
17.
嵌段共聚物F127高效分散单壁碳纳米管 总被引:1,自引:0,他引:1
利用浓硫酸和浓硝酸对单壁碳纳米管(SWNTs)进行氧化酸处理,制备羧基化单壁碳纳米管(SWNTsCOOH),以两亲性三嵌段聚醚Pluronic F127{(PEO)_(99)(PPO)_(65)(PEO)_(99)}为分散剂,制备SWNTs-COOH/F127分散液。采用激光粒度分析仪、傅里叶红外光谱、紫外-可见光吸收光谱、拉曼光谱对所制备分散液进行表征,并比较了SWNTs、F127修饰SWNTs、羧基化SWNTs、F127修饰羧基化SWNTs 4种水分散液的分散情况。结果表明,经混酸处理后,单壁碳纳米管表面成功修饰上羧基,相对于原始碳纳米管,其在水中的分散性及稳定性大大地提高。制备的SWNTs-COOH/F127分散液在4 000 r/min离心30 min未见沉淀,室温静置30 d以上不发生絮凝。 相似文献