聚酯/多壁碳纳米管复合导电纤维的制备及性能

以羧基化多壁碳纳米管(MWNT-COOH)为导电填料,采用双螺杆熔融挤出制备聚酯(PET)/MWNT-COOH共混切片,通过熔融纺丝得到PET/MWNT-COOH复合纤维。研究了MWNT-COOH含量和拉伸处理对复合纤维可纺性、导电性能、力学性能和表面形貌等的影响。结果表明:当MWNT-COOH质量分数小于1.0%时,切片具有较好的可纺性,初生纤维的导电逾渗阈值为0.5%~1.0%;MWNT-COOH的加入提高了纤维的断裂强度,当MWNT-COOH质量分数为0.1%时,纤维断裂强度提高约34%,随着MWNT-COOH含量增加,纤维断裂强度的增加幅度逐渐下降;拉伸会使MWNT-COOH沿纤维轴向取向,有利于MWNTCOOH间的互相搭接形成导电通路,提高纤维的导电性能。     

Preparation and properties of multi-walled carbon nanotube/carbon/polystyrene composites

Multi-walled carbon nanotube (MWCNT)/C/polystyrene (PS) composite materials were prepared by in situ polymerization of monomer in preformed MWCNT/C foams. MWCNT/C foams were preformed using polyurethane foam as template. The preformed MWCNT/C foams had a more continuous conductive structure than the carbon nanotube networks formed by free assembly in composites. The structure of the MWCNT/C foam network was characterized with scanning electron microscopy. The MWCNT/C/PS composites have an electric conductivity higher than 0.01 S/cm for a filler loading of 1 wt.%. Enhancement of thermal conductivity and mechanical properties by the preformed MWCNT/C foam were also observed.     

Preparation and properties of biodegradable PBS/multi-walled carbon nanotube nanocomposites

In this study, poly(butylene succinate)/multi-walled carbon nanotube (PBS/MWNT) hybrids were prepared by a melt-blending process. The carbon nanotubes (CNTs) were successfully modified using N,N′-dicyclohexylcarbodiimide (DCC) dehydrating agents. As a result, excellent dispersion of the modified carbon nanotubes (CNT-C18) in organic solvents was achieved. Subsequently, the PBS/CNT nanocomposites were prepared through facile melt blending. Mechanical properties, thermal behavior, conductivity of these resultant polymer/CNT composites were investigated. The results obtained show that the PBS/CNT-C18 nanocomposites consisting of well-dispersed nanotubes exhibited enhanced thermal and mechanical properties. With the addition of 3 wt% CNT-C18, T_d of the nanocomposite increased 12.3 °C as compared to that of the pristine PBS sample. Moreover, the increments of E′ and E″ of the nanocomposite at 25 °C were 120 and 55%, respectively. In the aspect of conductivity, the surface resistivity of the PBS/CNT-C18 composite was found to be 7.30 × 10⁶ Ω, which is a decrease of 10⁹ fold in value as compared to that of the pristine PBS sample. Such PBS/CNT-C18 sample exhibits high anti-static efficiency, which would be potentially useful in electronic packaging materials.     

Preparation and properties of graphene/multi-walled carbon nanotube/thermoplastic vulcanizate composites

通过熔融接枝共混制备了石墨烯（Ge）/多壁碳纳米管（MWCNTs）/聚丙烯（PP）母粒,然后与丁基橡胶动态硫化制备了Ge/MWCNTs/热塑性硫化胶（TPV）复合材料,考察了Ge/MWCNTs/TPV复合材料的相态结构、热电性能和力学性能。结果表明,Ge/MWCNTs作为异相成核剂能够提高PP的结晶温度;Ge/MWCNTs/TPV复合材料呈现“海-岛”结构,Ge和MWCNTs在PP相和橡塑两相界面分散均匀、与基体结合能力强。加入质量分数均为3%的Ge和MWCNTs时,Ge/MWCNTs/TPV复合材料的直流电导率提高5个数量级,热导率提高了36.7%,拉伸强度达17.3 MPa,扯断伸长率达260%。     

The thermal and mechanical properties of a polyurethane/multi-walled carbon nanotube composite

A polyurethane/multi-walled carbon nanotube elastomer composite was synthesized. The microstructure of the composite was examined by field-emission scanning electron microscopy and transmission electron microscopy. The thermal and mechanical properties of the composite were characterized by dynamic mechanical thermal analysis, thermogravimetric analysis and tensile testing. The chemical linkage of carbon nanotubes with polyurethane matrix was confirmed by Fourier transform infrared spectra. The study on the structure of the composite showed that carbon nanotubes could be dispersed in the polymer matrix well apart from a few of clusters. The results from thermal analysis indicated that the glass transition temperature of the composite was increased by about 10 °C and its thermal stability was obviously improved, in comparison with pure polyurethane. The investigation on the mechanical properties showed that the modulus and tensile strength could be obviously increased by adding 2 wt% (by weight) CNT to the matrix.     

Doped polyaniline/multi-walled carbon nanotube composites: Preparation, characterization and properties

This study reports the synthesis of doped polyaniline in its emeraldine salt form (PANI-ES) with carboxylic acid and acylchloride groups contained multi-walled carbon nanotubes (designated as c-MWNTs and a-MWNTs) by in situ polymerization. Both Raman spectra and HRTEM images indicate that carboxylic acid and acylchloride groups formed at both ends and on the sidewalls of the MWNTs. Based on the π-π* electron interaction between aniline monomers and functionalized MWNT and hydrogen bonding interaction between the amino groups of aniline monomers and the carboxylic acid/acylchloride groups of functionalized MWNT, aniline molecules were adsorbed and polymerized on the surface of MWNTs. Structural analysis by FESEM and HRTEM showed that PANI-ES/c-MWNT and PANI-ES/a-MWNT composites are core (c-MWNT or a-MWNT)- shell (doped-PANI-ES) tubular structures with diameters of several tens to hundreds of nanometers, depending on the PANI content. The conductivities of 0.5 wt% functionalized MWNT containing PANI-ES/c-MWNT and PANI-ES/a-MWNT composites are 60-70% higher than that of PANI without MWNT.     

Preparation of a carbon nanotube/carbon fiber multi-scale reinforcement by grafting multi-walled carbon nanotubes onto the fibers

To prepare a carbon nanotube (CNT)/carbon fiber multi-scale reinforcement (MSR), multi-walled carbon nanotubes (MWCNTs) functionalized at the end caps with hexamethylene diamine (HMD) are grafted onto the surfaces of carbon fibers treated with acyl chloride. The surface element concentrations, surface functional groups and morphology of the MSR were examined by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). XPS spectra indicate that sp² and sp³ carbon atoms are major components in the MSR surface, and the carbon fiber surface structure is not destroyed. There is 17.41% of C-NH_x in the surface of the MSR, which suggests that MWCNTs are covalently grafted onto carbon fiber surfaces. SEM shows that the grafted MWCNTs stick to the carbon fiber surface at different angles, and are uniformly distributed along the outer edges of the grooves in the fiber surface. The grafted MWCNTs are 50-200 nm in length and around 14 nm in diameter. It was found that the grafting increases the weight of carbon fiber by 1.2%, which implied that a considerable amount of MWCNTs were grafted onto carbon fiber surfaces.     

水性聚氨酯/环糊精修饰多壁碳纳米管复合材料的制备与性能

为改善多壁碳纳米管(MWNTs)的水分散性,将其与β-环糊精(CD)研磨以及超声分散,得到环糊精修饰碳纳米管(CDMWNTs),并通过与水性聚氨酯球磨共混,制备了水性聚氨酯/CD修饰碳纳米管复合乳液,其固化成膜后利用热重分析、万能材料试验机、扫描电镜和绝缘电阻测试仪探讨了CDMWNTs含量对复合胶膜热稳定性、力学性能、微观形貌和导电性的影响。通过粒径分析与红外光谱说明了CD改性处理对MWNTs的影响。结果显示,与纯聚氨酯胶膜相比,当CDMWNTs加入量为3.0%时,复合胶膜的拉伸强度和断裂伸长率分别提高了72.29%和17.22%;其电阻率为174?·m,减小了5个数量级,显著提高了聚氨酯的导电性;其热稳定性也得到一定的提高。相同加入量下,CDMWNTs所制复合胶膜的性能好于未改性MWNTs所制复合胶膜的性能。     

Preparation and photoelectrocatalytic properties of titania/carbon nanotube composite films

Composite films of TiO₂ and carbon nanotubes (CNTs) were prepared on titanium sheets by liquid phase deposition and the photoelectrocatalytic (PEC) properties of the films were investigated through the degradation of methyl orange (MO) in 0.1 M solutions. It was demonstrated that CNTs in the TiO₂ film significantly decreased the charge transfer resistance and increased the anodic photocurrent response of the film under UV light irradiation when the bias was above −0.1 V. The PEC performance of the CNT-based composite film could be tuned by controlling the preparation parameters including the deposition time and calcination temperature. The deposition time and calcination temperature were optimized at 1 h and 450 °C, respectively. On the TiO₂/CNT film prepared under the optimized conditions, 95% of the added MO (10 mg L⁻¹) was degraded within 90 min, which was much higher than the 60% removal seen on the pure TiO₂ films.     

Preparation and characterization of polyaniline/multi-walled carbon nanotube composites

This study describes the synthesis of doped polyaniline in its emeraldine salt form (PANI-ES) with carboxylic groups containing multi-walled carbon nanotubes (c-MWNTs) via in situ polymerization. Both Raman and FTIR spectra indicate that carboxylic acid groups formed at both ends and on the sidewalls of the MWNTs. Based on the π-π* electron interaction between aniline monomers and MWNT and hydrogen bonding interaction between the amino groups of aniline monomers and the carboxylic acid group of c-MWNT, aniline molecules were adsorbed and polymerized on the surface of MWNTs. Structural analysis using FESEM and HRTEM showed that PANI-ES/c-MWNT composites are core (c-MWNT)-shell (doped-PANI-ES) tubular structures with diameters of several tens to hundreds of nanometers, depending on the PANI content. The conductivities of these PANI-ES/c-MWNT composites are 50-70% higher than those of PANI without MWNT.     

Preparation of polyimide/multi-walled carbon nanotubes composite aerogels with anisotropic properties

In this study, a series of polyimide/multi-walled carbon nanotubes (PI/MWCNTs) composite aerogels with anisotropic properties were fabricated. First, the poly(amic acid) ammonium salt (PAS)/MWCNTs suspension was prepared by blending poly(amic acid), deionized water, triethylamine, MWCNTs, and CNT dispersant with the aid of ultrasonication treatment. Afterwards, the aqueous PAS/MWCNTs suspension was unidirectionally frozen at −65 ± 5°C, then followed by freeze-drying. Subsequently, the PI/MWCNTs composite aerogels were obtained after thermal imidization treatment. Morphology observations revealed that PI/MWCNTs composite aerogels exhibited a “hive-like” structure while viewed along the freezing direction, whereas a typical channel-like pore structure was observed perpendicular to the freezing direction. This typical structure rendered PI/MWCNTs composite aerogels with anisotropic properties such as heat conduction, electrical conductivity as well as electromagnetic interference shielding effectiveness when the aerogels were characterized at different directions.     

聚乙烯醇/磺酸化碳纳米管复合纤维的制备与性能研究

采用湿法纺丝法制备了聚乙烯醇/磺酸化多壁碳纳米管(PVA/s-MWCNTs)复合纤维,并对复合纤维的结构与性能进行了表征。结果表明:当纤维中s-MWCNTs质量分数为5%时,s-MWCNTs均匀地分散在PVA基体中,当s-MWCNTs质量分数增加到8%时,纤维中出现少许s-MWCNTs团聚体;随着s-MWCNTs含量的增加,复合纤维的结晶度逐渐降低,PVA微晶取向度先增大后减小,纤维的模量和断裂强度均先增大后减小,电导率逐渐增加;当s-MWCNTs质量分数为5%时,纤维力学性能较好,其断裂强度和模量分别为0.83GPa和15 GPa,而s-MWCNTs质量分数为8%时,纤维电学性能较好,其电导率为0.65 S/m。     

改性多壁碳纳米管／PA6纤维的制备及力学性能

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。     

Stress transfer in polyacrylonitrile/carbon nanotube composite fibers

Gel spun polyacrylonitrile/carbon nanotube (PAN/CNT) composite fibers have been produced, and the stress-induced G′ Raman band shifts in the CNTs have been monitored to observe stress transfer during fiber strain. Improvements in CNT quality, CNT dispersion, and post-processing fiber drawing are shown to increase the stress transfer from the matrix to the CNT. Radial breathing mode (RBM) intensity of specific CNT chiralities confirms CNT debundling during fiber processing. During PAN/CNT fiber straining, there reaches a plateau in the CNT G′ downshift, signifying that the stress on the CNT is maintained despite continued straining of the PAN/CNT fiber. Correlating CNT strain with CNT modulus and volume fraction allows for the interfacial shear strength (τ_i) of the PAN-CNT interface to be determined. The as-spun and fully drawn PAN/CNT-A (99/1) nano composite fibers exhibit τ_i of 13.1 and 30.9 MPa, respectively, while an improved CNT dispersion (PAN/CNT-A (99.9/0.1)) results in τ_i equal to 44.3 MPa.     

Rheological and electrical properties of polycarbonate/multi-walled carbon nanotube composites

Rheological and electrical properties of the polycarbonate (PC)/multi-walled carbon nanotube (MWNT) were studied. The MWNT was funtoinalized by treating with the hydrogen peroxide (H₂O₂). The H₂O₂ treated MWNT was dried by thermal and freeze drying methods. From the morphological studies, the degree of entanglement of the MWNT was decreased after treating with the H₂O₂. For the H₂O₂ treated MWNT (thermal drying), the length of the MWNT was shortened compared that of the H₂O₂ treated MWNT (freeze drying). The rheological and electrical properties of the PC/MWNT (H₂O₂ treated) composites increased compared that of the PC/MWNT (untreated) composites. Also, the electrical conductivity showed higher value for the PC/MWNT (H₂O₂ treated, freeze drying) composites compared that of the PC/MWNT (H₂O₂ treated, thermal drying) composites. From the results of the morphological, rheological, and electrical properties of the PC/MWNT composites, it is suggested that the electrical and rheological properties of the PC/MWNT composites are affected by the MWNT-MWNT network structure, which is related with the MWNT morphologies such as the degree of aggregation and aspect ratio of the MWNT.     

聚吖啶橙/碳纳米管修饰电极的构置及其应用

用染料吖啶橙非共价修饰碳纳米管,继而通过电聚合制得了性能优良的聚吖啶橙/碳纳米管(POAO/MWNT)修饰电极.该电极界面结构新颖,不仅具有碳纳米管独特的性质,而且能够展现出聚吖啶橙作为导电聚合物膜的性质.该修饰电极对多巴胺(DA)有优良的电催化氧化作用,催化还原峰电流与其浓度在1×10-6～5.0×10-3mol/L范围内呈良好的线性关系,检出限为1.0×10-7mol/L,可用于多巴胺针剂含量的测定.     

Electrical and piezoresistive properties of multi-walled carbon nanotube/polymer composite films aligned by an electric field

Aligned multi-walled carbon nanotube (MWCNT)/polymer composite films are prepared by solution casting in the presence of an alternating electric field. Application of 7 kV/m at a frequency of 60 Hz to the polymer composite melt induces MWCNT alignment in the direction of the applied field, which is maintained after polymer crystallization. The electrical conductivity and piezoresistive response of electric-field-aligned and randomly oriented 0.1–0.75 wt% MWCNT/polysulfone films are evaluated. Electrical conductivity is 3–5 orders of magnitude higher for composites with electric-field-aligned MWCNTs than for randomly oriented composites. MWCNT alignment inside the polymer matrix also increases the film piezoresistive sensitivity, enhancing the strain sensing capabilities of the composite film.     

A mesoporous composite template composed of self-assembled silica nanotube and multi-walled carbon nanotube

The multi-walled carbon nanotubes (MWNTs) were successfully embedded in the hexagonally-arranged silica tubular structure by the self-organization of two surfactant systems providing a MWNT-incorporated silica nancomposite template. The anionic surfactant (sodium dodecyl sulfate, SDS) adsorbed on the MWNT surfaces allowed the MWNTs to interact with the outer surface of the self-assembled non-ionic surfactant, poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) triblock copolymer. Due to the hydrophilic–hydrophilic interaction between the PEO blocks and the sulfate group of SDS, the MWNTs were most possibly surrounded by the outer wall of the SBA-15 hexagonal tubes aligning in the longitudinal and transverse directions to the silica tube direction. According to the interplanar distances, electron microscopy images, and N₂ adsorption–desorption isotherms, the synthesized SBA-15/MWNT system exhibited the structural integrity of silica-tube arrangement and structural characteristics of MWNTs in terms of BET surface area and micropore volume. This work made it clear that the developed SBA-15/MWNT template could be used to synthesize various MWNT-incorporated 2-D replicas.