丙烯腈-丁二烯-苯乙烯三元共聚物／碳纳米管复合材料电磁性能的初步研究

通过紫外光辐照制备了丙烯腈-丁二烯-苯乙烯三元共聚物脓纳米管（ABS／CNTs）复合材料。在CNTs的质量分数为5％时，复合材料体积电阻率（ρv）比基体树脂下降了10^7Ω·cm。在20～100℃温度范围内，复合材料的ρv受温度影响不大。扫描电镜观察表明：紫外光辐照下的CNTs在ABS基体中均匀分布，容易形成导电网络。复合材料在2～10GHz的微波频段内，具有较宽的介电损耗（约为21-50）。     

PLA/CNTs复合材料的3D打印制备及其电磁屏蔽性能研究

通过3D打印成型方式,制备多孔且具有较高内表面积的聚乳酸(PLA)基体,再通过浸渍工艺使碳纳米管(CNTs)附着在基体孔壁,成功制备了具有电磁屏蔽功能的PLA/CNTs复合材料。对复合材料进行了力学性能、电磁屏蔽性能、扫描电子显微镜(SEM)测试。结果表明:当CNTs含量为2%时,PLA/CNTs复合材料的电磁屏蔽性能高达40 dB。PLA/CNTs复合材料的力学性能也明显提高,突出了PLA/CNTs复合材料的优异性能,拓展了PLA/CNTs复合材料的应用领域。     

ABS/碳纳米管纳米复合材料的研究进展

综述了近年来丙烯腈-丁二烯-苯乙烯(ABS)/碳纳米管(CNTs)纳米复合材料的研究进展,介绍了该材料的不同制备方法和所得复合材料的力学、导电、雷达波吸收、热解及阻燃性能。研究发现,添加少量的CNTs可以大幅提高ABS的弹性模量、拉伸强度及模量等力学性能;降低材料的电阻率,达到永久抗静电型ABS要求;并可使材料具有雷达波吸收性能;同时还能显著改善ABS的阻燃性能。还分析了不同CNTs种类、添加量及预处理方法对ABS/ CNTs纳米复合材料上述性能的影响,并对相关机理进行了分析讨论。     

OMMT对PA6/ABS共混体系结晶行为及热力学性能的影响

采用有机蒙脱土(OMMT)、聚酰胺6(PA6)和丙烯腈-丁二烯-苯乙烯共聚物(ABS),通过熔融共混的方法制备了PA6/ABS/OMMT共混物。利用透射电子显微镜(TEM)、差示扫描量热仪(DSC)及动态热力学分析仪(DMA)研究了OMMT在PA6/ABS(70/30)合金体系中的分布和分散状况,以及PA6/ABS/OMMT共混体系的结晶行为和热力学性能。结果表明:OMMT片层主要分散于PA6相中,PA6与ABS的两相界面处亦存在少量OMMT片层。OMMT的加入降低了PA6/ABS共混体系的结晶温度,使PA6的结晶结构发生改变,说明OMMT具有一定的增容作用。引入OMMT后,PA6/ABS共混体系的储能模量有所提升,玻璃化转变温度则变化较小。     

碳纳米管填料静电自组装制备及在导电塑料中的应用

为了提高碳纳米管(CNTs)在塑料中的分散性能,设计碳纳米管填料(CNTs Filler)。阳/非离子表面活性剂复配在水中分散CNTs,并赋予CNTs表面正电性。与表面负电性的炭黑或聚苯乙烯微球复合,通过静电吸附作用自组装形成均匀稳定的复合物,制备出CNTs Filler。对比了CNTs Filler、CNTs和炭黑在PS和ABS塑料中,经不同成型工艺的导电结果,证明了使用碳纳米管填料提高了碳纳米管在塑料中的分散性能,总结了碳纳米管相对炭黑作为塑料导电功能体适合压延成型加工。推荐碳纳米管用于导电片材、导电薄膜和高导电塑料等领域。     

等离子体条件下煤基富勒烯的制备及生成机理

以淄博贫煤为原料，用射频等离子体法合成碳纳米管（carbon nanotubes，CNTs）和纳米洋葱状富勒烯（nano—structured onion—like fullerenes，NSOFs），运用场发射扫描电子显微镜（FE—SEM）和高分辨透射电子显微镜（HRTEM）对产物进行了表征和分析．结果表明：以淄博贫煤为原料制备出CNTs和NSOFs，CNTs直径分布均匀，约为10nm左右，准球状的NSOFs直径分布在8nm-30nm之间，石墨化程度较高；并对不同变质程度的煤制备富勒烯的生成机理进行了比较与讨论．     

紫外辐照诱导等离子体喷涂氧化钛涂层的生物活性

采用大气等离子体喷涂技术在钛合金表面上制备常规和纳米结构TiO2涂层.考察了TiO2涂层经紫外光辐照后浸泡于模拟体液(simulatedbody fluid,SBF)中的生物活性.研究涂层表面状态、紫外光辐照时间和辐照介质对TiO2涂层生物活性的影响.结果表明:经紫外光辐照后的纳米TiO2涂 层在SBF中可诱导类骨磷灰石在其表面形成,显示了良好的生物活性,但常规TiO2涂层和磨去表面的纳米TiO2涂层无此种现象发生.紫外光辐照处 理时间增长有利于类骨磷灰右的生成.在SBF、水、空气中进行紫外光辐照的纳米TiO2涂层表面均有类骨磷灰石生成,但在水中进行紫外光辐照处 理的涂层显示较低的生物活性.     

微波辅助制备TiO_2/CNTs复合材料及可见光光催化性能研究

文章以六氟钛酸铵、硼酸、碳纳米管为反应物,在低温(100℃)和常压体系下,采用微波辅助法制备二氧化钛/碳纳米管复合材料(TiO_2/CNTs)光催化剂。采用X射线粉末衍射(XRD)、场发射扫描电子显微镜(FESEM)及紫外-可见漫反射光谱对TiO_2/CNTs进行表征。采用TiO_2/CNTs为催化剂光催化降解罗丹明B,研究了TiO_2/CNTs的可见光光催化活性。测试结果表明,在可见光照射下制备得到的TiO_2/CNTs具有比Degussa P25光催化剂更优越的光催化降解活性。     

2种不同激光对钛宝石辐照作用的研究

分别采用波长为193 nm的ArF准分子激光与波长为800 nm、脉冲宽度为120 fs的飞秒激光对温梯法生长的钛宝石进行辐照,并对辐照前后的吸收谱、荧光谱及电子顺磁共振(EPR)谱进行了检测。2种不同辐照的结果表明:218 nm及266 nm吸收峰并不是完全由同一种色心所引起的。通过对比不同品质因数(FOM)值的钛宝石样品在420 nm处的荧光谱,发现准分子激光辐照后420 nm处荧光强度降低,表明样品中Ti~(4 )离子浓度降低。而在飞秒激光辐照下荧光强度增大,即Ti~(4 )浓度增大。根据2种激光的波长,功率密度及辐照方式的差异对于2种辐照产生不同结果做出了解释。     

稀土钐聚丙烯酰胺发光材料的合成及性能

以钐离子为中心体,利用二苯甲酰基甲烷(DBM)为第一配体,1,10-菲罗啉(phen)为第二配体与氯化钐在乙醇中反应,加入钆离子(Gd~(3+))对其敏化,合成了具有发光性能的稀土钐三元配合物Sm/Gd(DBM)3phen。将钐三元配合物与丙烯酰胺(AM)进行共聚反应,制备了一种键合型稀土聚丙烯酰胺共聚物[Sm/Gd(DBM)3phen/PAM]。通过元素分析、傅里叶变换红外光谱、紫外光谱、荧光光谱分析、热重分析测定了配合物及共聚物的组成、结构、发光性能及稳定性。结果表明:Sm/Gd(DBM)3phen/PAM的发光性能优于Sm/Gd(DBM)3phen,在紫外光的激发下于559、597、643 nm处发射出Sm~(3+)的4G5/2—6H5/2、4G5/2—6H7/2、4G5/2—6H9/2跃迁特征荧光。其中,不发光的Gd~(3+)对于发光的Sm~(3+)有明显的荧光增强作用。     

Electrical and mechanical properties of acrylonitrile‐butadiene‐styrene/multiwall carbon nanotube nanocomposites prepared by melt‐blending

The electrical properties in polymer/carbon nanotube (CNT) nanocomposites are governed not only by the degree of dispersion but also to a greater extent on the aspect ratio of the CNTs in the final composites. Melt‐mixing of polymer and CNTs at high shear rate usually breaks the CNTS that lowers the aspect ratio of the nanotubes. Thus, homogeneous dispersion of CNTs while retaining the aspect ratio is a major challenge in melt‐mixing. Here, we demonstrate a novel method that involves melt‐blending of acrylonitrile‐butadiene‐styrene (ABS) and in situ polymerized polystyrene (PS)/multiwalled CNT (MWCNT) nanocomposites, to prepare electrically conducting ABS/MWCNT nanocomposites with very low CNT loading than reported. The rationale behind choosing PS/MWCNT as blending component was that ABS is reported to form miscible blend with the PS. Thus, (80/20 w/w) ABS/(PS/MWCNT) nanocomposites obtained by melt‐blending showed electrical conductivity value ≈1.27 × 10^?6 S cm^?1 at MWCNT loading close to 0.64 wt %, which is quite lower than previously reported value for ABS/MWCNT system prepared via solution blending. Scanning electron microscopy and differential scanning calorimetry analysis indicated the formation of homogenous and miscible blend of ABS and PS. The high temperature (100°C) storage modulus of ABS (1298 MPa) in the nanocomposites was increased to 1696 MPa in presence of 0.64 wt % of the MWCNT. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Chitosan/CNTs nanocomposite as green carrier material for pesticides controlled release

Chitosan-based nanocomposites containing gamma-treated carbon nanotubes (CNTs) were developed for controlled release of pesticide. The CNTs were irradiated under gamma irradiation in air at different doses. The transmission electron microscopic images of gamma-treated CNTs showed disentanglement of the tubes without distorting their tubular structure which effectively increased the dispersion properties of CNTs in nanocomposites. X-ray diffraction analysis of CNTs showed some structural changes, and an irradiation dose of 150 kGy is the most effective. Azinphos methyl (AZM) was selected as a model drug, and its release was studied using HPLC technique. Controlled release response of CNTs-based nanocomposites opens a new avenue for pesticides applications because it requires less quantity of pesticides. As a result, the side effects of pesticide in our environment are minimized.     

Blends of Nylon-66 with Chemically Modified ABS (m-ABS) Using a Novel Method of UV Irradiation

Blends of Nylon-66/ABS were prepared in various proportions. ABS was chemically modified using ethylene glycol, ethylene diamine and acrylamide. Butadiene region of ABS acted as site for modification reactions, irradiated by UV using UV initiator in UV reactor. m-ABS were characterized using FTIR confirming chemical functionalization. m-ABS blended with Nylon-66 and results compared with original ABS/N-66 blends. Physical, mechanical, chemical, electrical and thermal properties were characterized, and properties of modified blends were superior to conventional blends. Functional groups increases polarity of polymer enhancing miscibility of blends. SEM photographs gives evidence for miscibility of blends.     

Aligned carbon nanotubes by catalytic decomposition of C2H2 over Ni–Cr alloy

High density, well-aligned carbon nanotubes (CNTs) were prepared by thermally decomposing acetylene at 700 °C with the help of Ni–Cr alloy as catalyst in a thermal chemical vapor deposition system. The density and alignment of CNTs were characterized by scanning electron microscope (SEM). It was found that the density of the CNTs could be remarkably increased and the alignment could be improved with the decrease of the thickness ratio of Ni:Cr. Also found in our experiment was that the catalyst encapsulated in CNT was single crystal Ni, which was confirmed by high-resolution transmission electron microscopy (HRTEM) and electron dispersion X-ray spectrum (EDX). Finally, the growth mode of CNTs was discussed based on the Ni–Cr alloy catalysts under our experimental conditions. The results are helpful in providing a better understanding of the acting of catalyst and the controlling of the desirable density and alignment of CNTs for various applications.     

Three-dimensional heterostructure of metallic nanoparticles and carbon nanotubes as potential nanofiller

ABSTRACT: The effect of the dimensionality of metallic nanoparticle-and carbon nanotube-based fillers on the mechanical properties of an acrylonitrile butadiene styrene (ABS) polymer matrix was examined. ABS composite films, reinforced with low dimensional metallic nanoparticles (MNPs, 0-D) and carbon nanotubes (CNTs, 1-D) as nanofillers, were fabricated by a combination of wet phase inversion and hot pressing. The tensile strength and elongation of the ABS composite were increased by 39% and 6%, respectively, by adding a mixture of MNPs and CNTs with a total concentration of 2 wt%. However, the tensile strength and elongation of the ABS composite were found to be significantly increased by 62% and 55%, respectively, upon addition of 3-D heterostructures with a total concentration of 2 wt%. The 3-D heterostructures were composed of multiple CNTs grown radially on the surface of MNP cores, resembling a sea urchin. The mechanical properties of the ABS/3-D heterostructured nanofiller composite films were much improved compared to those of an ABS/mixture of 0-D and 1-D nanofillers composite films at various filler concentrations. This suggests that the 3-D heterostructure of the MNPs and CNTs plays a key role as a strong reinforcing agent in supporting the polymer matrix and simultaneously serves as a discrete force-transfer medium to transfer the loaded tension throughout the polymer matrix.     

Multiwalled Carbon Nanotubes/CsPbX3@Polyacrylonitrile Core/Shell Nanofibers with Ultrahigh Water,Thermal, and Ultraviolet Stability

The application of all-inorganic perovskite nanocrystals (PNCs) is considerably limited by their inherent instability under the ubiquitous environmental conditions with high water content, temperature, and UV intensity. The multiwalled carbon nanotubes (CNTs) are combined with polyacrylonitrile (PAN) for the first time to improve the uniform luminous performance and environmental stability of PNCs, attributing to the dense growth of PNC via lead ions bound with rich carbonylation on CNT surfaces, the excellent characteristics of CNTs (including hydrophobicity, electrical conductivity, specific heat, UV absorption capacity), the weather resistance of PAN polymer, and their synergistic effect. Here, via one-step single-nozzle electrospinning at room temperature, CNTs, PNCs, and PAN are comprised as core–shell nanofibers (i.e., CNTs/PNCs@PAN) with tunable emissions between 472 and 683 nm, covering the visible light range from blue to red. The photoluminescence intensity of CNTs/CsPbBr₃@PAN can be 93%, 91%, and 91% of the initial value, respectively, after being immersed in water for 20 days, heated to 90 °C, and exposed to 365 nm light irradiation for 48 h, which are superior to those of the previously reported PNCs/PAN fibers. The ultrahigh water stability is further proven by CNTs/PNCs@PAN-based sensor for rhodamine 6G solution fluorescence detection.     

Preparation and Electron Beam Irradiation of PVC/ENR/CNTs Nanocomposites

Poly (vinyl chloride), PVC/epoxidized natural rubber blend, ENR/carbon nanotubes, CNTs nanocomposites were prepared using melt intercalation and solution blending methods. In both preparation methods PVC: ENR: CNTs ratios were fixed at 50:50:2, while the 50/50 PVC/ENR blend without the addition of CNTs was used as control. The PVC/ENR/CNTs nanocomposites were exposed to electron beam (EB) irradiation at doses ranging from 0–200 kGy. The effects of two different preparation methods on the tensile properties, gel fraction and morphology of the PVC/ENR/CNTs nanocomposites were studied. Prior to EB irradiation, the addition of 2 phr of CNTs caused a drop in the tensile strength (Ts) of the 50/50 PVC/ENR blend, implying poor distribution of CNTs in the PVC/ENR blend matrix. However upon EB irradiation, the nanocomposites prepared by the melt blending method exhibited higher values of Ts as compared to the neat PVC/ENR blend due to occurrence of radiation-induced cross-linking in the PVC/ENR blend matrix. Transmission electron microscopy (TEM) images proved that a better dispersion of CNTs in PVC/ENR blend matrix can be achieved by melt intercalation compared to solution blending and the dispersion of CNTs was improved by irradiation. Scanning electron microscopy (SEM) results showed a distinct failure surface with formation of rough structure for the irradiated nanocomposites, which explains the higher values of tensile properties compared to the non-irradiated nanocomposites.     

Mechanical properties and deformation behaviors of acrylonitrile‐butadiene‐styrene under Izod impact test and uniaxial tension at various strain rates

Two polybutadiene‐graft‐acrylonitrile‐styrene copolymer (PBD‐g‐SAN) impact modifiers with different rubber particle size were synthesized by seeded emulsion polymerization. Acrylonitrile‐butadiene‐styrene (ABS) blends with a constant rubber concentration of 15 wt% were prepared by blending those impact modifiers and SAN resin. The major focus was the mechanical properties and deformation mechanisms of ABS blends under Izod impact test and uniaxial tension at various strain rates from 2.564 × 10^?4 S^?1 upto 1.282 × 10^?1 S^?1. By the combination of transmission electron microscope and scanning electron microscope, it was concluded that crazes and cavitation coexisted in ABS blends. The deformation mechanisms of ABS blend containing large rubber particles was rubber particles cavitation and shear yielding in the matrix including crazes, and they do not change with the strain rate. Different from ABS blend with large rubber particles, deformation mechanism of ABS with small rubber particles under tensile condition was only involved in shear yielding in the matrix and no crazes were formed. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Preparation, Characterization, and Photocatalytic Properties of CaNb2O6 Nanoparticles

CaNb₂O₆ nanoparticles with a size range of 30–50 nm were synthesized by heat treatment at 600°C after a solvothermal process and their optical and photocatalytic properties were investigated. The prepared powders were characterized by X-ray powder diffractometer, field-emission scanning electron microscope, transmission electron microscope, UV-Vis diffuse reflectance spectroscopy, Fluorescence spectroscopy, and Raman spectroscopy. Compared with a powder of the same material prepared by a solid-state reaction (SS) method, the nanoparticles exhibited a higher Brunauer–Emmett–Teller (BET) surface area, more efficient light absorption, and enhanced photocatalytic activity for producing H₂ from pure water under UV irradiation. The photoluminescence spectra revealed that a radiative recombination process is dominant in the powder prepared by the SS method (strong blue emission at 300 K) under UV light irradiation, while no obvious emission was observed in the nanoparticles. This decrease of the radiative recombination as well as the higher optical absorption ability and higher BET surface area resulting from the reduced dimensionality led to enhanced photocatalytic activity of the nanoparticles.