乙烯类聚合物-炭黑复合物的PTC效应

本文以低密度聚乙烯(LDPE)和乙烯-醋酸乙烯酯共聚物(EVA)为基材,炭黑(CB)为导电微粒,探讨了聚合物-炭黑复合物的结构对正温度系数效应(PTC)增强与减弱的影响和炭黑含量与PTC效应的关系以及交联结构对PTC现象的稳定作用.     

对苯乙烯磺酸钠改性炭黑对天然橡胶胶乳力学性能的影响

在Haake转矩流变仪的热机械作用下,用对苯乙烯磺酸钠(NASS)对炭黑进行预处理,制备了在水介质中具有优异的分散稳定性的亲水性纳米炭黑粒子(PNASS-CB),并将其直接用于天然橡胶胶乳的补强研究.1HNMR和FT-IR结果表明NASS在炭黑表面成功聚合包覆,用热重分析方法计算其包覆率为8.1 wt%,接枝率为2.5 wt%.亲水性炭黑的表面自由能降低,同时,Payne效应和结合胶含量表明亲水性炭黑粒子与橡胶的相互作用强于亲水性炭黑粒子之间的相互作用.因此,亲水性炭黑/天然橡胶胶乳复合材料的硫化时间变短,转化速度加快,硫化胶的撕裂强度提高了85%,拉伸强度提高了30%,断裂伸长率提高了20%.     

粘胶/炭黑复合纤维素纤维的结构与性能研究

将炭黑水悬浮溶液与粘胶原液共混制得不同添加比例的纺丝溶液,通过湿法纺丝制备炭黑复合粘胶纤维。采用扫描电镜(SEM)、广角X射线衍射仪(WAXD)及纤度强度仪等分析所制备纤维的结构与性能。WAXD分析结果表明,不同添加比例炭黑的复合纤维均为纤维素Ⅱ型晶体结构,结晶度随着炭黑添加量的增加逐渐降低;SEM结果显示,不同添加比例的炭黑在粘胶基体中的分布都较均匀,没有明显团聚现象,但是随着添加量的增加,纤维的孔隙增大增多,光滑性下降,但纤维仍然保持锯齿截面形状;对纤维力学性能分析结果表明,添加适量的炭黑可使复合纤维素纤维力学性能提高,而添加过量时,力学性能反而降低。     

炭黑吸附法制备掺杂镨TiO2纳米粉体及其光催化性能

以硝酸镨为掺杂的前驱物,钛酸异丙酯为TiO2的前驱物,通过炭黑吸附高温水热法制得掺杂镨的量为0.07%的纳米Pr3+/TiO2粉体。分别采用热重/差热分析(TG-DTA)、X射线衍射(XRD)、扫描电镜(SEM)、紫外可见分析(UV-VIS)和比表面积吸附(BET)对不同焙烧温度下所得粉体的物相、颗粒度、分散性及光吸收性能进行表征和分析。实验结果表明:炭黑的吸附阻止了粉体在干燥和煅烧阶段的团聚和烧结,制得的Pr3+/TiO2纳米粉体团聚较少,呈现良好的分散性,颗粒均匀,经500℃焙烧,得到纳米粉体平均颗粒直径为18 nm,比表面积为78.08 g.m-2。光催化降解实验表明,炭黑吸附后TiO2的光催化活性在一定时间内比没有炭黑的提高了将近2倍,在紫外灯照射下Pr3+/TiO2能在60 min内对亚甲基蓝的降解率达到93%。     

天然橡胶原位接枝炭黑的分散性研究

采用原位固相接枝方法,使在高温和强剪切作用下降解的天然橡胶接枝到炭黑表面.采用透射电镜(TEM)、原子力显微镜(AFM)等方法观察了接枝前后的炭黑粒子形貌变化,发现未接枝炭黑以微米级的附聚体形式存在,而由于炭黑聚集体被强剪切力部分破坏,接枝炭黑的聚集程度明显减弱,粒子的尺寸减小.采用激光光散射粒度仪对接枝前后炭黑的粒度进行分析,接枝炭黑的体积平均粒径为164 nm,远小于测得的原炭黑的粒径797 nm.采用沉降法、透光率法及zeta电位测量研究了接枝改性对炭黑在溶剂中的分散性及分散稳定性的影响,结果表明,接枝炭黑在接枝分子的溶剂中的分散性变好,分散稳定性提高.     

炭黑填充顺丁橡胶(BR)复合材料中多重相互作用的研究

通过溶液浸泡及高速离心的方法分离了填料与聚合物间的强弱相互作用,研究了炭黑填充BR复合材料中多重相互作用与炭黑含量的关系,基于不同结合橡胶含量与储能模量的关系,提出了该多重相互作用随炭黑含量的演变模型.结果表明,存在于炭黑凝胶Ⅰ中的玻璃化转变温度和结晶熔融峰在炭黑凝胶Ⅱ中均完全消失,该现象意味着炭黑凝胶Ⅰ中测得的玻璃化转变及结晶行为只是与炭黑形成弱相互作用的那部分分子链段的贡献.在选用玻璃化转变温度考察炭黑-橡胶相互作用时应综合考虑样品特性以及测试方法.当炭黑含量不高于50 phr时,结合橡胶Ⅱ的含量随炭黑含量的增多呈线性增大,结合橡胶Ⅲ的含量则受炭黑含量的显著影响.炭黑填充橡胶复合材料中的多重相互作用可通过重叠模型进行描述,当炭黑含量分别为25~30phr,50~55 phr以及70~80 phr时,填充复合材料体系中分别存在结合橡胶Ⅲ的重叠层,结合橡胶Ⅲ和结合橡胶Ⅱ的重叠层,以及结合橡胶II的重叠层.     

热重分析法测试玻纤增强PP和改性PA6塑料中低含量炭黑的研究

采用热重分析法(TGA法),分别以通用塑料中的玻纤增强PP和工程塑料中的改性PA6为代表,首先重点研究塑料体系中低含量(小于1％)炭黑测试的通用关键影响因素,随后验证低含量炭黑测试方法的测试准确性和通用性,最后简要分析造成上述两种材料中低含量炭黑结果差异性的原因.结果表明:测试分段程序和处理程序的选择、坩埚的影响和空白...     

导电炭黑在聚丙烯/极性聚合物体系中的选择性分散及其对导电性能的影响

以聚丙烯(PP)和极性聚合物的共混物为基体材料,以导电炭黑为填料,通过熔融共混制备导电复合材料。探讨了导电炭黑在两相基体中的分散情况以及双基体各组分比例对复合体系结构形态和导电性能的影响。SEM测试结果表明:炭黑粒子选择性地分散在极性乙烯-丙烯酸共聚物(EAA)树脂或尼龙6(PA6)中。EAA相在PP基体中呈棒状伸长结构,且随着EAA树脂含量的增大,在PP基体中形成更多更为连续的棒状伸长结构,使体积电阻率迅速下降。当在体系中加入PA6,mPP/mPA6=80/20时,PA6在PP基体中形成相互连接的纤维状分散结构,显著降低了复合体系的体积电阻率。电性能测试结果表明:材料在相同导电炭黑含量下的体积电阻率相对单基体体系可降低3~7个数量级。     

HPLC分析炭黑原料油中多环芳烃

炭黑原料油中多环芳烃(PAH)含量是最重要的质量指示,然而目前尚未建立有效的分析方法。本文提出了反相HPLC分析方法,根据炭黑生成的机理及煤焦油产品的主要组成分布,选定分析双环的萘、联苯,三环的芴、菲、蒽,四环的萤蒽、芘、(艹屈)来表征炭黑原料油中整体PAH含量。本法经对某炭     

调节氧化镉-炭黑界面高效电催化CO2还原生成CO

通过调节氧化镉与炭黑之间的界面实现了高效电化学二氧化碳还原. 不同氧化镉和炭黑含量的 CdO/CB复合材料利用超声处理方法制备. 采用X射线衍射、 X射线光电子能谱和透射电子显微镜对所得复合材料进行表征, 揭示了其结构组成和形貌. 用H型电解池对CdO/CB复合材料电催化二氧化碳还原的性能进行测试发现, CdO质量分数为20%的CdO/CB 可在-1.0 V(vs. RHE)电位下获得高达92.7%的总法拉第效率, 而纯CdO在相同条件下的法拉第效率仅为69.5%. CO的法拉第效率最高可达87.4%. 进一步的对比实验和动力学研究结果表明, CdO/CB具有更高的电催化CO₂还原性能源于复合材料中氧化镉与炭黑之间的界面和高接触面积. 此外, CdO/CB可在至少10 h的二氧化碳电还原反应中保持稳定的CO法拉第效率.     

超声引发自由基聚合制备聚苯乙烯磺酸钠接枝炭黑

通过在超声环境下,单体苯乙烯磺酸钠发生自由基聚合,生成的聚合物长链自由基被炭黑表面捕获,制备聚合物接枝炭黑.借助红外光谱、热重、粒度、透射电镜和zeta电位分析对该接枝炭黑进行表征.同时研究超声条件对接枝率的影响.结果表明,单体聚合并接枝到炭黑表面,同时炭黑的附聚体和一些大的聚集体结构被超声破碎,平均粒径大为减小;在300W超声波输出功率下,反应1h后,接枝率达到12.8%并趋于稳定.由于接枝分子链上磺酸基的存在,接枝炭黑在水中的分散稳定性显著改善.     

CB在PET-PE复合材料中的选择分散及电性能

用Haake转矩流变仪制备了聚对苯二甲酸乙二酯-聚乙烯-炭黑(PET-PE-CB)复合材料.通过溶解性试验、扫描电镜测试对CB在PET-PE多相体系中的选择性分散进行了研究,考察了CB分布对电性能的影响.结果表明:CB倾向于分布在PET相,改变CB填充量、基体配比以及加料次序对CB微观分布的影响不大.当m(CB)/m(PET-PE)=0.07时,出现渗滤现象.固定炭黑含量,当PET的质量分数由20%增加到60%时,材料的体积电阻率下降了6个数量级,一次性加料更有利于形成导电通路,可以获得较低的体积电阻.     

Conductivity of Poly(methyl methacrylate)/Polystyrene/Carbon Black and Poly(ethyl methacrylate)/Polystyrene/Carbon Black Ternary Composite Films

Poly(methyl methacrylate)(PMMA)/polystyrene(PS)/carbon black(CB)and poly(ethyl methacrylate)(PEMA)/PS/CB ternary composite films were obtained using solution casting technique to investigate double percolation effect.In both PMMA/PS/CB and PEMA/PS/CB ternary composite films,the CB particles prefer to locate into PS phase based on the results of calculating wetting coefficient,which is also confirmed by SEM images.The conductivity of the films was investigated,and the percolation threshold(￠c)of both ternary composite films with different polymer blend ratios was determined by fitting the McLachlan GEM equation.Conductivity of PMMA/PS/CB ternary composite films showed a typical double percolation effect.However,due to the double emulsion structure of PEMA/PS polymer blends,the PEMA/PS/CB ternary composite films(PEMA/PS=50/50)showed a higher￠c,even CB only located in PS phase,which conflicts with the double percolation effect.A schematic diagram combined with SEM images was proposed to explain this phenomenon.     

Relationship between electrical resistivity and particle dispersion state for carbon black filled poly (ethylene-<Emphasis Type="Italic">co</Emphasis>-vinyl acetate)/poly (<Emphasis Type="SmallCaps">L</Emphasis>-lactic acid) blend

It is known that the electrical volume resistivity of insulating polymers filled with conductive fillers suddenly decreases at a certain content of filler. This phenomenon is called percolation. Therefore, it is known that controlling resistivity in the semi-conductive region for carbon black (CB) filled composites is very difficult. When poly (ethylene-co-vinyl acetate) (EVA) is used as a matrix, the percolation curve becomes gradual because CB particles disperse well in EVA. In this study, the relationship between the dispersion state of CB particles and electrical resistivity for EVA/poly (L-lactic acid) (PLLA) filled with CB composite was investigated. The apparent phase separation was seen in the SEM photograph. It was predicted that the CB particles located into the EVA phase in the light of thermodynamical consideration, which was estimated from the wetting coefficient between polymer matrix and CB particles. The total surface area per unit mass of dispersed CB particles in the polymer blend matrix was estimated from small-angle X-ray scattering and the volume resistivity decreased with increasing CB content. The values of the surface area of CB particles in CB filled EVA/PLLA (25/75 wt%) and EVA/PLLA (50/50 wt%) polymer blends showed a value similar to that of the CB filled EVA single polymer matrix. In electrical volume resistivity measurement, moreover, the slopes of percolation curves of EVA/PLLA (25/75 wt%) and EVA/PLLA (50/50 wt%) filled with CB composite are similar to that of EVA single polymer filled with CB composite. As a result, it was found that CB particles selectively locate in the EVA phase, and then the particle forms conductive networks similar to the networks in the case of EVA single polymer used as a matrix.     

Functionalized Carbon Black Nanospheres Hybrid with MoS2 Nanoclusters for the Effective Electrocatalytic Reduction of Chloramphenicol

Synthesis of nanomaterials using cheap and highly efficient material is an important aspect of nanotechnology. In this present work, we have used the carbon black (CB) as a highly conductive and inexpensive carbonaceous material for the fabrication of the electrochemical sensor. However, the poor dispersion in water obstructs the usage of CB in electrochemical sensor and biosensor applications. Hence, the CB was functionalized by simple reflux method and the functionalized CB (f‐CB) nanospheres hybrids with hydrothermally synthesized MoS₂ nanoclusters by simple ultrasonication process. In addition, the various suitable spectrometric techniques used to probe the surface morphology and chemical modification of the prepared materials. The prepared MoS₂ and f‐CB nanohybrids (f‐CB/MoS₂) applied for the electrocatalytic reduction of toxic chloramphenicol (CAP). Fascinatingly, the f‐CB/MoS₂ modified electrode showed a competitive electrocatalytic performance comparing with other modified electrodes. At the optimized condition, the sensor exhibited the LOD about 0.002 μM, wider linear range 0.015 to 1370 μM with the sensitivity of 3400 μA μM⁻¹ cm⁻² for the determination of CAP. Moreover, the practical viability of the sensor was exploited in milk powder and honey samples.     

Electrochemical Sensor Based on Casein and Carbon Black for Bisphenol A Detection

Bisphenol A (BPA) is an environmental endocrine disrupting chemical, which can lead to various adverse health effects. Aiming to develop effective tools for the detection of BPA, this work reports a low cost and stable film based on casein (CAS) and Carbon Black (CB). The proposed material (CAS‐CB) showed structures of CAS surrounded by CB agglomerates observed by Scanning Electron Microscopy while Fourier Transform Infrared Spectroscopy analysis illustrated characteristic bands of casein. Cyclic Voltammetry (CV) and linear sweep voltammetry (LSV) were used to investigate the electrochemical behavior of BPA using the CAS‐CB. Under optimal conditions, LSV detection presented a limit of detection of 0.25 μmol L^?1 in a linear range from 0.49 to 24 μmol L^?1. Additionally, the working electrode (GC) modified by the proposed film (CAS‐CB) was applied for BPA sensing in environmental and milk samples. The results showed recoveries between 95.4 to 114 % attesting the efficiency of this new material, which has simplicity in the preparation, high conductivity, and adsorption capability.     

改性纳米炭黑/聚氨酯复合物的制备及表征

利用有机硅偶联剂改性的纳米炭黑和聚氨酯制备了纳米炭黑/聚氨酯复合物. 采用红外光谱、透射电镜、流变学及力学性能等测试方法对纳米粒子及其聚氨酯复合物进行了表征. 红外光谱表明, 纳米粒子的存在使聚氨酯的氢键结构发生了改变. 适量改性纳米炭黑粒子明显提高了聚氨酯的拉伸强度和断裂伸长率等力学性能. 流变学测试结果表明, 溶液中改性纳米炭黑粒子与聚氨酯分子间存在明显的相互作用.     

CB填充聚合物导电复合体系熔体聚集态结构演化

本文试图在低频率（ω）及小应变条件下,追踪粒子填充导电复合材料微观结构的变化与发展,并通过修正的KerneNielson 方程对材料的聚集态结构进行研究.     

Acetylcholinesterase Biosensor Based on Reduced Graphene Oxide – Carbon Black Composite for Determination of Reversible Inhibitors

For the first time, acetylcholinesterase (AChE) biosensors based on mixed carbon nanomaterials (electrochemically reduced graphene oxide (ERGO) and carbon black (CB) particles) were described for the determination of antidementia drugs. Changes in the content of underlying layer allowed varying selectivity and sensitivity of the inhibitor determination. Appropriate limits of detection (LOD) varied in the range from 1 pM to 0.1 nM for donepezil, 5 nM–0.1 μM for berberine, 0.1–50 nM for huperzine A and 0.1–300 nM for galantamine. Variation in the inhibition measurement parameters can be used for increasing selectivity of the measurements.     

LDPE／CPE／炭黑三相复合导电体系的电学性能

研究了ＬＤＰＥ／ＣＰＥ／炭黑三相复合导电体系的导性能和电流－电压特性。实验结果表明复合体系具有明显的导电渗滤效应，在共混比ＬＤＰＥ／ＣＰＥ＞５０／５０时，导电性能随ＣＰＥ含量增加而显著提高，这主要是由于炭黑粒子在ＬＤＰＥ和ＣＰＥ两组分分中的分布不均匀性所致。