Grafting of hyperbranched poly(amidoamine) onto carbon black surfaces using dendrimer synthesis methodology

To modify carbon black surface, the surface grafting of hyperbranched poly(amidoamine) onto the surface by using dendrimer synthesis methodology was investigated. Carbon black having amino groups (initiator sites) was prepared by the reduction of surface nitro groups introduced by nitration of aromatic rings. It was found that hyperbranched poly(amidoamine) was propagated from carbon black surface by repeating two processes: (1) Michael addition of methyl acrylate (MA) to surface amino groups and (2) amidation of the resulting esters with ethylenediamine: the percentage of poly(amidoamine) grafting reached to 96.2% after 10th‐generation. The grafting of hyperbranched poly(amidoamine) onto polystyrene‐bead as a model compound of carbon black was also achieved by the above procedures. However, the theoretical propagation of poly(amidoamine) dendrimer was not achieved, because of steric hindrance of grafted polymer. Hyperbranched poly(amidoamine)‐grafted carbon black gave a stable dispersion in a good solvent for poly(amidoamine). Copyright © 2001 John Wiley & Sons, Ltd.     

Immobilization of capsaicin onto silica nanoparticle surface and stimulus properties of the capsaicin‐immobilized silica

To prepare silica nanoparticle having biorepellent activity, the immobilization of capsaicin onto hyperbranched poly(amidoamine) (PAMAM)‐grafted silica was investigated. Grafting of PAMAM onto a silica surface was achieved in a solvent‐free dry system using PAMAM dendrimer synthesis methodology. The immobilization of capsaicin was achieved by the reaction of hydroxyl groups of capsaicin with isocyanate groups of Silica‐PAMAM, which were introduced by the reaction of terminal amino groups of Silica‐PAMAM with hexamethylene diisocyanate. The immobilization of capsaicin was confirmed by thermal decomposition GC‐MS. The amount of capsaicin immobilized onto PAMAM‐grafted silica was determined to be 0.10 mmol/g. Capsaicin‐immobilized Silica‐PAMAM (Silica‐PAMAM‐Cap) was dispersed uniformly in water and Tyrode solution. Stimulus activity of Silica‐PAMAM‐Cap was estimated using two stimulus tests, that is a magnus test and a paw licking test, to sensory nerve of mice. As the result of magnus test, it was found that the Silica‐PAMAM‐Cap shows stimulus activity. It was found that elution of capsaicin could be depressed by immobilizing capsaicin onto Silica‐PAMAM from the result of paw licking test. In addition, the stimulus property of Silica‐PAMAM‐Cap to the human skin could be observed and it was found that Silica‐PAMAM‐Cap had acrid taste. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1800–1805, 2010     

Immobilization of flame retardant onto silica nanoparticle surface and properties of epoxy resin filled with the flame retardant‐immobilized silica

To prepare silica nanoparticle having flame retardant activity, the immobilization of flame retardant onto hyperbranched poly(amidoamine) (PAMAM)‐grafted silica was investigated. Grafting of PAMAM onto a silica surface was achieved in a solvent‐free dry‐system using PAMAM dendrimer synthesis methodology. The immobilization of bromine flame retardant, poly(2,2′,6,6′‐tetrabromobisphenol‐A) diglycidyl ether (PTBBA), was successfully achieved by the reaction of terminal amino groups of PAMAM‐grafted silica (Silica‐PAMAM) with epoxy groups of PTBBA. The immobilization of PTBBA was confirmed by FTIR and thermal decomposition GC‐MS. The amount of PTBBA immobilized onto Silica‐PAMAM was determined to be 60 wt %. PTBBA‐immobilized Silica‐PAMAM (Silica‐PAMAM‐PTBBA) was dispersed uniformly in a epoxy resin, and the epoxy resin was cured in the presence of hexamethylenediamine. Flame retardant activity of the epoxy resin filled with Silica‐PAMAM‐PTBBA was estimated by limiting oxygen index (LOI). The LOI of epoxy resin filled with Silica‐PAMAM‐PTBBA was higher than that filled with untreated silica and free PTBBA. It was confirmed that the flame retardant activity of epoxy resin was improved by the addition of the Silica‐PAMAM‐PTBBA. The elimination of PTBBA from the epoxy resin filled with Silica‐PAMAM‐PTBBA into boiling water was hardly observed by immobilization of PTBBA onto silica surface. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6145–6152, 2009     

Preparation and mechanical properties of water-dispersible hyperbranched polymer grafted carbon black/natural rubber composites by latex blending method

In order to improve the mechanical properties of rubber-matrix composites, carboxyl-terminated hyperbranched poly (2-hydroxypropane-1,2,3-tricarboxylic acid) grafted carbon black (CB-g-CTHBP) was prepared, and it could be stably dispersed in water for up to 90 days. CB-g-CTHBP dispersion and natural rubber latex were blended to obtain NR/CB-g-CTHBP, and the effect of CB-g-CTHBP content on the mechanical properties of composites was discussed. The results show that the dispersibility and wettability of CB-g-CTHBP to composites are significantly improved after grafting hyperbranched polymer onto the surface. Compared with the composite filled with NR/CB, when the amount of filler is 30 phr, tensile strength, tear strength, and shore A hardness of NR/CB-g-CTHBP increase by 54.78%, 55.13%, and 20.96%, respectively. Moreover, CB-g-CTHBP could disperse more evenly in the natural rubber-matrix, and the interaction between CB-g-CTHBP and rubber-matrix could further enhance in the composite.     

Grafting of maleic anhydride onto carbon black surface via ultrasonic irradiation

The grafting of maleic anhydride onto carbon black surface based on the Diels–Alder addition via ultrasonic irradiation was investigated. Fourier transform infrared spectroscopy (FT‐IR) and thermogravimetric analysis (TGA) were used to determine the chemical structure of the resulting products. The anhydride ring in the modified products can be opened into two carboxylic groups. Accordingly, the carboxylated carbon black was analyzed quantitatively through acid‐based titration to determine the concentration of anhydride ring on the modified carbon black's surface. The grafted molecules amount calculated from the concentration of the anhydride ring was consistent with the results of TGA data. Comparison of zeta potential measurement demonstrated that there were more negative charges attached to the surface of carbon black after ultrasonic modification. TEM observations showed that the conglomeration degree of modified carbon black decreased more than that of initial carbon black. Copyright © 2008 John Wiley & Sons, Ltd.     

Radical graft polymerization of vinyl monomers onto nanoparticles in ionic liquid initiated by azo groups introduced onto the surface

The radical graft polymerization of vinyl monomers, such as styrene and methyl methacrylate, initiated by azo groups introduced onto silica nanoparticle and carbon black surfaces in room temperature ionic liquid (IL) were investigated. In this work, 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C₄mim][PF₆]) was used as IL. The percentage of polystyrene and poly(methyl methacrylate) grafting onto silica nanoparticle and carbon black increased with increasing reaction time. The percentage of grafting in IL was much larger than that in 1,4‐dioxane. The molecular weight of polystyrene grafted onto the silica surface in IL was almost equal to that in 1,4‐dioxane. The result indicates that the amount of grafted polystyrene in IL is five times that in 1,4‐dioxane. This may be due to the fact that lifetime of the surface radical formed by the group of azo is prolonged because of high viscosity of IL. Therefore, the surface azo groups were effectively used as initiating sites for the graft polymerization. In addition, the reduction of waste solvent was achieved by use of IL as reaction solvent, because unreacted monomer could be removed under vacuum after the reaction and the reuse of IL was easily achieved. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1143–1149, 2007     

Complementary effects of multiwalled carbon nanotubes and conductive carbon black on polyamide 6

This article introduces a newly innovative idea for preparation of superconductive ternary polymeric composites of polyamide 6 (PA6), conductive carbon black (CCB), and multiwalled carbon nanotubes (MWCNTs) with different weight ratios by a melt‐mixing technique. The complementary effects of CCB and MWCNTs at different compositions on rheological, physical, morphological, thermal, and dynamic mechanical and electrical properties of the ternary composites have been examined systematically. We have used a novel formulation to produce high‐weight fraction ternary polymer composites that show extremely higher conductivity when compared with their corresponding binary polymer composites at the same carbon loading. For example, with an addition of 10 wt % MWCNTs into the CCB/PA6 composite preloaded with 10 wt % CCB, the electrical conductivity of these ternary composites was about 5 S/m, which was 10 times that of the CCB/PA6 binary composite (0.5 S/m) and 125 times that of the MWCNT/PA6 binary composite (0.04 S/m) at 20 wt % carbon loading. The incorporation of the MWCNTs effectively enhanced the thermal stability and crystallization of the PA6 matrix in the CCB/PA6 composites through heterogeneous nucleation. The MWCNTs appeared to significantly affect the mechanical and rheological properties of the PA6 in the CCB/PA6 composites, a way notably dependent on the MWCNT contents. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1203–1212, 2010     

Conductivities and spectroscopic studies on hyperbranched polyurethane electrolytes

Polymer electrolytes were prepared with hyperbranched polyurethane, linear polyurethane as the host polymer, and lithium perchlorate (LiClO₄) as the ion source. Fourier transform infrared spectra were used to analyze the bonding degree of Li⁺ with carbonyl and ether groups. Raman spectra were applied to analyze the aggregate degree of anion perchlorate ion (ClO). The spectra analysis indicated that the hyperbranched polyurethane could function as a “solvent” for the lithium salt. Also, the conductivity increased with increasing concentration of hyperbranched polymers in the host polymer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 120–126, 2003     

ATRP of butyl acrylates from functionalized carbon black surfaces

The functionalization of carbon black surface with atom transfer radical polymerization (ATRP) initiating sites and subsequent ATRP of n‐butyl acrylate (n‐BA) and t‐butyl acrylate (t‐BA) from the surface of carbon black is reported. The polymerizations were carried out using CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as the primary catalytic system in anisole at 70 °C. The initiator density on carbon black surface was tuned and the effect of initiator density on the polymers grafted on the surface was illustrated. Polymerizations were also performed in the presence of a sacrificial initiator to indirectly monitor the molecular weight evolution of polymers formed in the system. Block copolymerization of t‐BA initiated from poly(n‐BA) grafted carbon black was conducted to achieve water‐dispersible carbon black composites after cleavage of the t‐butyl groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4695–4709, 2005     

Synthesis of a novel one‐pot approach of hyperbranched polyurethanes and their properties

A new method for the synthesis of hyperbranched polymers involving the use of AB_x macromonomers containing linear units have been investigated. Two types of novel hyperbranched polyurethanes have been synthesized by a one‐pot approach. The structures of monomers and polymers were characterized by elemental analysis, ¹H NMR, ¹³C NMR, Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetric analysis. The hyperbranched polymers have been proven to be extremely soluble in a wide range of solvents. Polymer electrolytes were prepared with hyperbranched polymer, linear polymer as the host, and lithium perchlorate (LiClO₄) as the ion source. Analysis of the isotherm conductivity dependence of the ion concentration indicated that these hyperbranched polymers could function as a “solvent” for the lithium salt. The conductivity increased with the increasing concentration of hyperbranched polymers in the host polymer. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 344–350, 2002     

Synthesis and ionic conductivity of hyperbranched poly(glycidol)

A novel hyperbranched poly(glycidol) (HPG) was prepared and characterized. The synthesized HPG was used as a substrate of a polymer electrolyte. The ionic conductivity of a blend of HPG, polyurethane (PU), and salt was studied. The ionic conductivity of HPG/PU/LiClO₄ was about 6.6 × 10^?6 S · cm^?1 at 20 °C and 6.3 × 10^?4 S · cm^?1 at 60 °C. The results indicated that HPG showed higher solubility for salt than linear polyether when both had the same [O]/[Li⁺] molar ratio. The main reason was that more cavities and a lower degree of chain entanglement in HPG resulted in a lower glass‐transition temperature and were beneficial for decreasing the aggregation of salt or enhancing the ionic conductivity. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2225–2230, 2001     

Synthesis of comb‐like dispersants and a study on the effect of dispersant architecture and carbon black dispersion

Comb dispersants suitable for stabilization of carbonaceous deposits found in automotive lubricating oils were derived from the copolymerization of vinyl‐ether terminated polyisobutylene (VE‐PIB) macromonomers with maleic anhydride (MAH). The rate and degree of copolymerization of VE‐PIB with MAH was greatly influenced by the molecular weight of the VE‐PIB. Longer PIB tails imposed greater hindrance of the chain end resulting in slower propagation and lower degrees of copolymerization for PIB‐alt‐MAH copolymers. Functionalization of PIB‐alt‐MAH with a polyamine proceeded smoothly at elevated temperatures as evidenced by disappearance of anhydride stretches via Fourier transform infrared spectroscopy. Analogous linear and grafted dispersants were prepared to investigate the influence of architecture on the physical properties of the dispersants. Characterization of the intermediates and final dispersants was conducted by nuclear magnetic resonance, gel permeation chromatography, thermogravimetric analysis, and ultraviolet–visible. Using Langmuir adsorption studies and carbon black as a substitute for carbonaceous deposits, it was found that comb and grafted dispersants exhibit greater affinities for adsorption but decreased packing efficiencies in comparison to linear dispersants. Rheological studies investigating viscosity as a function of loading for dispersant/oil mixtures with carbon black present a similar finding. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1682–1696     

Difference in bound rubber formation of silica and carbon black with styrene‐butadiene rubber

Formation of bound rubber is affected by the physical structure and surface chemistry of filler and the property of rubber. Variation of the bound rubber formation in styrene‐butadiene rubber compounds filled with silica and/or carbon black was studied. Influence of temperature on extraction of loosely bound rubber was also investigated. For the both silica and carbon black‐filled compounds, the bound rubber content increases with increase in the silica content ratio. The bound rubber content decreases with increasing the extracting temperature. The loosely bound rubber content of the silica‐filled compound is higher than that of the carbon black‐filled one. Activation energy for the extraction of the unbound and loosely bound rubbers becomes higher as the total filler content increases. The activation energy of the silica‐filled compound is higher (almost double the value) than for the carbon black‐filled one. Copyright­© 2002 John Wiley & Sons, Ltd.     

甲烷在石墨化热解碳黑和活性炭上的吸附

为研究影响碳基吸附剂吸附超临界温度气体的主要因素,选择石墨化热解碳黑BP280和Ajax活性炭,分析超临界温度高压甲烷在其上的吸附平衡。应用容积法,在压力0~20.5 MPa、温度253 K~313 K测定甲烷的吸附平衡数据,并由等量吸附线标绘和亨利定律常数确定等量吸附热。引入通用吸附等温方程,再由方程的Langmuir标绘确定最大吸附容量,进而通过方程的线性化计算吸附平衡态中甲烷分子的作用能。结果表明,甲烷在两种吸附剂上的最大吸附容量均随温度而变化,并都小于液态甲烷的密度;甲烷在碳黑和活性炭上的等量吸附热分别为11.9 kJ/mol~12.5 kJ/mol和17.5 kJ/mol~22.5 kJ/mol,体现了两种吸附剂不同的表面能量分布;甲烷分子间作用能随吸附量的变化特点反映了超临界温度甲烷以类似于压缩气体状态聚集的特点和吸附剂结构上的差异。碳基吸附剂的比表面积和微孔容积是影响其储存甲烷容量的重要因素。     

Solid phase microextraction using fused silica fibers coated with graphitized carbon black

Summary This paper presents the results obtained using fused-silica fibers coated with graphitized carbon black (Carbograph-Alltech) for solid-phase microextraction (SPME). The extraction and calibration curves relative to organic micro-pollutants present in gaseous and aqueous samples are reported. Examples of applications of this extraction procedure to GC and GC-MS analysis of organic micro-pollutants in actual samples are also reported.     

Fractal behaviour of carbon black and smectite dispersions by small angle neutron scattering

From dielectric spectroscopy on mechanically sheared dispersions of carbon black in mineral oil it was known that the distribution of relaxation times was invariant irrespective of the applied shear rate. From this observation fractal behaviour was suspected and a small angle neutron scattering experiment was set up for confirmation. Indeed, by this experiment a fractal dimension has been found of d=2.19, a value which is perfectly comparable tod=2.0 found by dielectric spectroscopy.The dielectric behaviour of the smectite dispersion is different from the carbon black and small angle neutron scattering confirms this. Ad-value of 2.8 has been found, pointing to a more compact object than could be expected from a fractal.     

Influence of thermoplastic spacer on the mechanical,electrical, and thermal properties of carbon black filled epoxy adhesives

A new approach of mimicking the selective localization mechanism of conductive filler into one phase of immiscible polymer blend system is proposed here, where a moderate fine of polymethylmethacrylate (PMMA) powder is prepared and used as the spacer in the carbon black (CB) filled epoxy adhesives system that can be applied at room temperature. The main purpose of PMMA‐spacer is to promote the formation of conductive networks via aiding the 3D self‐assembly of CB filler, selectively in the continuous phase of epoxy. PMMA‐spacer content ranged from 10, 20, 30, 40, and 50 vol.% were investigated under electrical, mechanical, and thermal properties for both unfilled and 15 vol.% CB filled system. With the incorporation of 10 vol.% PMMA‐spacer, the filled system shows promising improvement in electrical conductivity, with three order of magnitude increment at 15 vol.% CB loading. Toughening mechanism of epoxy was observed, where crack deflection upon the PMMA‐spacer is observed under scanning electron microscopy characterization and agreed by fracture toughness calculation. Thermal stability and coefficient of thermal expansion were improved at the minimum addition of PMMA‐spacer content, at 10 vol.%, while a small reduction in flexural strength is observed because of the poor interface interaction between the PMMA‐spacer and epoxy matrix. Interestingly, a limited interaction between the PMMA‐spacer with epoxy at the curing temperature of 100°C is observed, indicating the solubility of PMMA‐spacer in epoxy before crosslinking process occurred. Copyright © 2016 John Wiley & Sons, Ltd.     

Fe/炭黑、Ni/炭黑催化剂对渣油加氢反应的影响

使用模型化合物在微型反应釜中研究了载体炭黑对渣油内部氢转移反应的影响。结果表明,炭黑可以明显地促进四氢萘到蒽的氢转移反应。使用等体积浸渍法制备了Fe/炭黑、Ni/炭黑催化剂并对Fe/炭黑催化剂进行了XRD、SEM表征,结果表明,金属硫化物附着在炭黑颗粒的表面,直径为1μm左右。在高压反应釜中研究了载体炭黑和以炭黑为载体的催化剂对克拉玛依常压渣油430℃加氢反应的影响,并于传统的水溶性分散型催化剂的抑焦性能进行了对比。 结果表明,Fe/炭黑、Ni/炭黑催化剂可以明显地抑制渣油加氢反应的生焦,水洗后的催化剂效果比未经水洗的催化剂抑制生焦的效果好;Ni/炭黑催化剂抑焦效果比Fe/炭黑催化剂好;Fe/炭黑催化剂比同等浓度的水溶性Fe催化剂抑焦效果好。对反应产物馏分的分析表明,Fe/炭黑催化剂可以有效地抑制渣油缩合生焦,同时在一定程度上抑制裂化反应。     

Polymer grafting onto carbon black by use of TEMPO-terminated polystyrene with controlled molecular weight

The grafting of polystyrene with controlled molecular weight and narrow molecular weight distribution onto the carbon black surface through the trapping of polymer radicals formed by the thermal dissociation of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO)-terminated polystyrene (PSt-TEMPO) by the carbon black surface was investigated. PSt-TEMPO was prepared by living radical polymerization of St with the benzoyl peroxide/TEMPO system. When PSt having no terminal TEMPO moiety was heated with carbon black, no grafting of PSt onto the surface was observed. On the contrary, by the heating of PSt-TEMPO with carbon black in m-xylene at 125°C, PSt with controlled molecular weight and narrow molecular weight distribution was grafted onto the surface: the percentage grafting of PSt (M_n = 3.2 × 10³;M_w/M_n = 1.07) onto furnace black was determined to be 16.0%. On the basis of the above results, it is concluded that PSt radicals formed by the thermal dissociation of the C ON bond between PSt and TEMPO are trapped by polycondensed aromatic rings of carbon black. The mole number of grafted PSt chains on the carbon black surface decreased with increasing molecular weight of PSt-TEMPO. PSt-grafted carbon black gave a stable colloidal dispersion in THF. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 3165–3172, 1998     

Study on synthesis of poly(N‐isopropylacrylamide) grafted carbon black and temperature‐dependence conductivity of grafted carbon black/epoxy composites

Carbon black nanoparticle grafted with poly(N‐isopropylacrylamide) (CB‐g‐PNIPAAm) was synthesized by surface‐initiated atom transfer radical polymerization (SI‐ATRP). The temperature‐responsive behavior of CB‐g‐PNIPAAm was proved by temperature‐variable ¹H NMR. A temperature‐dependent conductive composite was prepared by blending CB‐g‐PNIPAAm with epoxy resin. The relationship between temperature and resistivity of the composite was studied: the composite exhibited a negative temperature coefficient (NTC) phenomenon. Possible mechanism for the NTC phenomenon was suggested. The results showed that resultant composites can be used in intelligent temperature‐switching. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1529–1535, 2008