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采用两步法,以聚乙烯吡咯烷酮(PVP)为表面活性剂,制备了不同种类的纳米冷冻机油并对其分散稳定性进行了实验研究。采用Hot Disk热常数分析仪,测量了40℃下纳米冷冻机油(纳米材料为TiO2、Al2O3、Fe2O3、石墨和碳纳米管,体积分数为0.05%、0.1%、0.2%、0.5%、1%和2%)的热导率,分析研究了颗粒体积分数、粒径、材质以及表面活性剂等因素的影响。结果表明:纳米冷冻机油的热导率随着颗粒体积分数的提高而增大;相同体积分数下随着颗粒粒径的增大而减小,而相同粒径下又随着颗粒材质热导率的提高而增大;同时分散稳定性优的纳米冷冻机油热导率较高。基于纳米粒子的体积分数、粒径、团聚理论和布朗运动开发了纳米冷冻机油热导率预测模型,并与实验数据进行比较,发现预测值与90%的实验数据偏差在±3%以内,平均偏差1.6%。 相似文献
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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
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采用低温化学气相沉积法裂解乙醇协同制备氢气和多璧碳纳米管,乙醇作为碳源,Ni/C用作催化剂。考察反应温度和Ni/C比例对氢气的产率和碳纳米管品质的影响。多壁碳纳米管结构与组成通过扫描电镜、投射电镜和X射线粉末衍射进行表征。结果表明:Ni/C催化剂最佳Ni担载量为8%,最佳的反应温度为500℃,最佳条件下氢气的产率为79%,碳纳米管的品质最佳。 相似文献
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采用柔和混合法制备纳米粒子良好分散的尼龙-6/多壁碳纳米管(PA6/MWNTs)复合材料,采用差示扫描量热仪(DSC)和广角X射线衍射法(XRD)研究了MWNTs对PA6基体结晶熔融行为的影响。DSC结果表明,MWNTs的加入大幅度地提高了PA6的结晶温度(最高提高约20℃),基体的结晶度也有所提高,说明良好分散的MWNTs在PA6结晶过程中呈现明显的异相成核作用;XRD结果证实,分散良好的MWNT促进PA6形成α晶型,抑制γ晶型的形成。同时,MWNT的加入导致复合材料出现熔融双峰现象,其形状随MWNT含量的变化而改变,双峰结构可能是由于熔融过程中伴随着重结晶而引起的。 相似文献
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配制了将不同含量的多壁碳纳米管（MWCNT）加入复合吸附剂13X/MgCl2中制成的新型复合吸附剂,并对其吸附、脱附和导热性能进行了测试。实验结果表明：新型复合吸附剂在闭式200℃脱附完成后,新型复合吸附剂的吸附残余量随着MWCNT含量的升高而减小,13X的吸附残余量是MWCNT含量最高的13X/MgCl2/MWCNT（CNT-5）复合吸附剂的吸附残余量的2倍,虽然MWCNT的加入不会对13X/MgCl2复合吸附剂在室温下的吸附性能有影响,CNT-5在开式、闭式的平衡吸附量可以达到0.52 g·g-1和0.38 g·g-1,分别是13X吸附量（0.24 g·g-1）的2.2和1.6倍,但新型复合吸附剂可以脱附更多的水蒸气。新型复合吸附剂的热导率随着MWCNT含量的增大而升高,CNT-5的热导率可以达到0.265 W·m-1·K-1,是13X热导率的4.9倍。 相似文献
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摘要：将可膨胀石墨(KPEG)和多壁碳纳米管(MWNTs)混合填料填充至聚丙烯(PP)制备PP/KPEG/MWNTs导热复合材料。保持混合填料总质量分数30%不变,改变两者质量比进行试验。结果表明,随着MWNTs填充比例增加,导热复合材料的拉伸强度呈先增大后减小趋势,而缺口冲击强度总体呈下降趋势。与纯PP相比,当MWNTs与KPEG质量比为1∶5 (MWNTs质量分数为5%)时,导热复合材料的热导率提高了328.4%;MWNTs可提高复合材料热稳定性,但改变其与KPEG质量比在试验范围内对热稳定性影响较弱。 相似文献
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采用一步法将聚苯乙烯（PS）、苯乙烯-丙烯腈共聚物（SAN）和甲基丙烯酸甲酯-苯乙烯共聚物（MS）分别与聚碳酸酯（PC）、多壁碳纳米管（MWCNTs）熔融混合,得到PC/PS/MWCNTs、PC/SAN/MWCNTs和PC/MS/MWCNTs三种复合材料。透射电子显微镜和场发射扫描电子显微镜观察表明,MWCNTs选择性分散在PC相中,这与Sumita模型预测的结果完全吻合,且随着PS、SAN或MS含量的增加,体系的体积电阻率-苯乙烯系聚合物含量曲线能够很好地拟合到PC/MWCNTs体系的体积电阻率-MWCNTs有效体积浓度曲线上,体系的体积电阻率变化符合有效浓度的概念。 相似文献
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将多壁碳纳米管(MWNT)氧化后,酰氯化处理,在氨基封端的PA6聚合时加入,制备PA6／MWNT母粒,将母粒同PA6切片熔融共混纺丝,制备PA6／MWNT纤维。用INSTRON 1122型万能材料试验机测定纤维的力学性能。结果表明,改性MWNT的加入提高了PA6纤维的断裂强度,纤维中MWNT质量分数仅为0．05％时,纤维的断裂强度和初始模量最大,分别增加了60％和86％。用扫描电镜观察复合纤维的结构,发现MWNT均匀地分布在PA6中,并与PA6基体间有相互作用,沿纤维轴向取向。 相似文献
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N‐vinylcarbazole (NVC) was polymerized in bulk or in toluene in presence of multiwalled carbon nanotube (MWCNT) without any extraneous catalyst. The formation of polyN‐vinylcarbazole (PNVC) was endorsed by striking agreement of FTIR, fluorescence and UV‐visible spectroscopic, thermogravimetric stability, differential scanning calorimetry, and dielectric characteristics of this polymer with the corresponding literature data for authentic PNVC samples prepared by free radical or carbocationic initiation. The polymerization was supposed to be initiated by a single electron transfer between N lone pair of NVC and the electron deficient MWCNT moieties. While PNVC homopolymer is nonconducting (10?12 to 10?16 S/cm), a composite of PNVC with MWCNT isolated from the polymerization system showed high dc conductivity varying from 1.3 to 33 S/cm depending upon the extent of MWCNT loading in the composite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4121–4126, 2007 相似文献
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Yuhan Tian Jiachun Zhong Linqing Hu Xiaoyi Zheng Jie Cheng Zejun Pu 《Polymer Composites》2020,41(2):556-563
In this work, a facilitated physical dispersion technology was employed to prepare polymer-based antistatic composites using polyethersulfone (PES) as matrix and the acidulated multiwalled carbon nanotube (MWCNT) as nanofillers, scattering the PES resin in the deionized water contained MWCNT by the colloid mill to obtain MWCNT/PES emulsion and the MWCNT/PES composites were prepared by melt processing. The influence of dispersion technology about the MWCNT/PES composites on the mechanical, thermal, and electrical properties was investigated in detail. The morphology of the MWCNT/PES emulsion was investigated by transmission electron microscopy and scanning electron microscope, respectively. The results showed that the MWCNT nanoparticles were encapsulated in the PES microspheres homogeneously. In addition, the obtained MWCNT/PES composites showed higher glass transition temperature (T g) and initial thermal decomposition temperature (T5%). More importantly, the tensile strength and surface resistance of 3 wt% MWCNT/PES composites were up to 112 MPa and 106 Ω/m, respectively. Therefore, these high-performance polymer-based antistatic composites will have potential application in electronic devices applied with high temperature conditions. 相似文献
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Yi‐Jhen Wu Liang Chao Ko‐Shan Ho Ying‐Jie Huang Yu‐Lan Huang Chi‐Shiang Yang Bo‐Hao Tseng 《应用聚合物科学杂志》2012,124(6):5270-5278
A multiwalled carbon nanotubes (MWCNTs) were carboxylated after refluxing with sulfuric and nitric acids. These attached carboxylic acid groups were further condensated with o‐phenylene diamine into amide catalyzed by dicyclohexyl carbodiimide (DCC). The obtained amidized MWCNTs were in situ‐polymerized with aniline monomers to graft a conducting polyaniline (PANI) onto MWCNT (ES‐g‐MWCNTs) through the polymerization occurring in the ortho‐ and meta‐positions. The reduced conductivity of the MWCNT after carboxylation can be recovered after grafting with PANI, which owns a strong λmax at the near infrared region due to the extended conjugation from MWCNTs to PANI. Transmission electronic microscopic pictures show a gradual broadening of the MWCNT diameter after carboxylation, amidization, and polymerization. The weight loss from the thermogravimetric thermograms due to the carboxylations of MWCNTs, amidized MWCNTs, and the PANI grafted MWCNTs into CO2 can be used to estimate the degree of carboxylation, amidization, and grafting of PANI. The degree of carboxylation of MWCNT calculated from ESCA spectrum is around 23% close to that estimated from TGA thermogram. The doping level of redoped PANI‐grafted MWCNT is found to be 27.78% much less than the maximum 50% of neat PANI. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
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Multi‐walled carbon nanotubes (MWCNTs) were grown on a stainless steel mesh and decorated with nickel nanoparticles (Ni NPs). The developed Ni NP‐MWCNT material was then used as a cathode in an electrochemical batch reactor to electrocatalytically convert NAD+ to enzymatically‐active 1,4‐NADH. The regeneration of 1,4‐NADH was studied at various electrode potentials. At electrode potential of ?1.6 V, a very high recovery (relative amount of 1,4‐NADH in the product mixture) was obtained, 98 ± 1 %. In comparison, to achieve the same recovery on a non‐decorated MWCNT cathode, a much higher cathodic potential was needed (?2.3 V), establishing the importance of Ni NPs on the electrocatalytic activity in reducing NAD+ to 1,4‐NADH. It was postulated that hydrogen adsorbs on Ni NPs immobilized on MWCNTs to form Ni‐Hads, and this activated hydrogen rapidly reacts with neighbouring NAD‐radicals, preventing the dimerization of the latter species, ultimately yielding 1,4‐NADH. 相似文献
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吴唯;栾立醒;浦伟光;何三雄;陈玉洁 《中国塑料》2011,25(1):31-35
采用熔融共混法制备了聚丙烯/多壁碳纳米管(PP/MWNTs)与聚丙烯/纳米有机蒙脱土(PP/OMMT)复合材料,利用热重分析法研究了PP、PP/MWNTs及PP/OMMT在氮气气氛中的热降解过程,并采用Kissinger及Ozawa方法研究了复合材料的热降解动力学及热降解表观活化能.结果表明,MWNTs和OMMT的加入... 相似文献
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研究改性碳纳米管(CNTs)和复配CNTs用量对甲基乙烯基硅橡胶(MVQ)性能的影响。结果表明:随着改性CNTs用量增大,改性CNTs补强混炼胶的硫化程度提高,t90延长;硫化胶的邵尔A型硬度、100%定伸应力、撕裂强度、热扩散率和热导率增大,拉伸强度和DIN磨耗量变化不大,拉断伸长率减小,表面电阻率和体积电阻率减小但整体变化不大。复配CNTs补强胶料的性能变化规律与改性CNTs补强胶料相同,物理性能、导电性能和导热性能较好。 相似文献