Thermal and thermoelastic properties of fast extrusion furnace (FEF) carbon black loaded SBR vulcanizates

The effect of FEF carbon black as filler on the thermal capacity c, diffusivity a, and thermal conductivity λ, of styrene butadiene rubber (SBR) composites in the temperature range 300–420 K was studied. The filler strongly increases the thermal diffusivity, whilst strongly decreasing the thermal capacity and the thermal conductivity (except at high FEF content ≥80 phr). The influence of the filler on the thermoelastic behaviour of the same composites was also investigated. It was found that the thermoelastic temperature change (ΔT) increased with carbon black concentration as well as the entropy change per unit extension.     

导电硅橡胶导电性和电热性的研究

对乙炔炭黑作导电填料的导电硅橡胶的导电性和电热性进行了研究。结果表明，由乙炔炭黑用量和渗滤阈可以预测和控制导电硅橡胶的体积电阻率；导电硅橡胶的电阻－温度变化规律符合隧道效应理论模型，导电硅橡胶的电压－电流特性呈非线性欧姆性，且乙炔炭黑用量越大，电压－电流特性的非线性欧姆性越显著；发热量与热损耗量达到平衡时，导电硅橡胶的表面温度可维持140℃，导电硅橡胶可作面状发热体使用；在满足导电性能的前提下，为保证导电硅橡胶良好的物理性能，应控制乙炔炭黑用量。     

导电炭黑/氯化丁基橡胶力学和电性能的研究

通过共混法制备了导电炭黑/氯化丁基橡胶复合材料,研究了复合材料的拉伸性能与导电、介电性能。研究发现,随着导电炭黑和硫化剂含量的增加,拉伸强度先出现一个极大值随后下降,在炭黑用量为5%,硫化剂用量为3%时,拉伸强度最大,为9.1 MPa;而断裂伸长率一直下降。当导电炭黑超过5%以后,电导率迅速增加,出现渗流现象。介电常数实部ε′和介电损耗因子tanδ随导电炭黑用量的增加而增大,但当导电炭黑用量较高(20%)时,在高频时,ε′和tanδ都下降。     

Effect of ultrasonic extrusion of star styrene-butadiene rubber on properties of carbon black- and silica-filled compounds and vulcanizates

Extrusion of star styrene-butadiene rubber (SBR) without and with ultrasonic treatment at amplitudes 3.5, 5, 7.5, and 10 μm was carried out. The molecular structure of untreated and treated star SBR was determined. Significant reduction of die pressure was observed during ultrasonic treatment due to the thixotropic and degradation effects. Ultrasonic treatment of star SBR at 3.5 μm created molecules of higher molecular weight via long-chain branching without gel formation. Ultrasonic treatment of star SBR at 5 μm created a small amount of gel. At high ultrasonic amplitudes more gel was generated hindering mixing of star SBR with silica. Extruded star SBR was compounded with carbon black and precipitated silica, with and without silane. It was found that the long-chain branching induced by ultrasonic treatment improved the rubber–filler interaction in precipitated silica without silane, as confirmed by the increase of bound rubber content. The filler–filler interaction was reduced in silica compounds without silane, as indicated by study of Payne effect. The significantly improved rubber–filler interaction and reduced filler–filler interaction led to an increase of the modulus at 100% elongation and tensile strength of SBR/silica vulcanizates. Extensive comparisons were made with earlier study on ultrasonic treatment of linear SBR. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47451.     

2种导电炭黑复合橡胶体系的导热性能研究

研究了2种导电炭黑复合天然橡胶材料的导热性能随着温度和填料用量的变化规律。结果表明,温度对于导电炭黑复合体系导热性能的影响不大。乙炔黑复合体系具有极高的导热性能,随着炭黑用量的增加,其导热性能优势越加明显。据透射电镜观察填料的微观形态,乙炔黑链枝状结构丰富,聚集体之间以面接触为主,这是其复合橡胶导热性能优异的原因,乙炔黑复合材料的热导率与炭黑体积分数呈线性关系。40B2复合体系的热导率与炭黑体积分数呈现逾渗规律,逾渗阈值在炭黑体积分数8.30%至13.63%之间。据扫描电镜观察复合材料的微观结构,逾渗现象与炭黑在基体内的分布密切相关。为更精确地描述填料用量与复合体系热导率的关系,对2种复合体系的热导率与炭黑的体积分数进行了回归。     

炭黑填充橡胶的热传导理论模型及应用研究

在研究炭黑填充橡胶传热机理的基础上建立热传导模型,推导出热导率计算方程。用该式分别估算了炭黑N330和N134填充橡胶的热导率,与试验结果对比发现,在较高炭黑用量下,热导率的理论预测值与试验值具有较好的一致性。对理论公式进行修正后获得炭黑填充橡胶热导率预测的半经验公式。     

Effect of carbon black/nanoclay hybrid filler on the dynamic properties of natural rubber vulcanizates

In this study, natural rubber (NR) nanocomposites based on carbon black (CB) and two poly(ethylene glycol) (PEG)‐modified clay hybrid filler were fabricated. The morphology and mechanical properties were studied. The dynamic properties of NR vulcanizates were investigated over a range of strain amplitude at two temperatures. It was found that NR with hybrid filler exhibits superior mechanical properties over that with CB as single phase filler. The hybrid filler causes a significant alteration in the dynamic properties of rubber. The Payne effect becomes more pronounced in rubber with modified clay. A decrease in loss factor (tanδ) was observed for rubber with hybrid filler also. The results revealed that the inclusion of nanoclay (NC) could induce a stronger and more developed filler network. Because of the anisotropy of the nanolayers, NC would depress the reconstruction of filler network, or lower the reformation rates when broken down under deformation, giving rise to lower tanδ value at broad temperature range as well as strain amplitude. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

炭黑在天然橡胶/溶聚丁苯橡胶硫化胶中的分散及其对性能的影响

考察了溶聚丁苯橡胶(SSBR)用量、炭黑的种类及用量对天然橡胶(NR)/SSBR硫化胶动态力学性能和力学性能的影响.结果表明,炭黑与SSBR的结合作用比与NR弱;随SSBR用量的增加,炭黑在NR/SSBR共混硫化胶中的分散性提高,Payne效应减弱,频率敏感性增强;随SSBR用量的增加,NR/SSBR共混硫化胶的拉伸强度和撕裂强度减小,扯断伸长率变化不大;而定伸应力则呈先减小后增大的趋势;随不同种类的炭黑在NR/SSBR硫化胶中分散性的提高,定伸应力呈上升趋势,损耗因子和压缩生热呈减小趋势.     

On the potential of organoclay with respect to conventional fillers (carbon black,silica) for epoxidized natural rubber compatibilized natural rubber vulcanizates

Onium modified montmorillonite (organoclay) was compounded with natural rubber (NR) in an internal mixer and cured by using a conventional sulfuric system. Epoxidized natural rubber with 50 mol % epoxidation (ENR 50) in 10 parts per hundred rubber (phr) was used as a compatibilizer in this study. For comparison purposes, two commercial fillers: carbon black (grade N330) and silica (grade vulcasil‐S) were used. Cure characteristics were carried out on a Monsanto MDR2000 Rheometer. Organoclay filled vulcanizate showed the lowest values of torque maximum, torque minimum, scorch, and cure times. The kinetics of cure reaction showed organoclay could behave as a cocuring agent. The mechanical testing of the vulcanizates involved the determination of tensile and tear properties. The improvement of tensile strength, elongation at break, and tear properties in organoclay filled vulcanizate were significantly higher compared to silica and carbon black filled vulcanizates. In terms of reinforcing efficiency (RE), organoclay exhibited the highest stiffness followed by silica and carbon black filled vulcanizates. Scanning electron microscopy revealed that incorporation of various types of fillers has transformed the failure mechanism of the resulting NR vulcanizates compared to the gum vulcanizates. Dynamic mechanical thermal analysis (DMTA) revealed that the stiffness and molecular relaxation of NR vulcanizates are strongly affected by the filler–rubber interactions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2438–2445, 2004     

Influence of carbon black and plasticisers on dynamic properties of isotropic magnetosensitive natural rubber

Abstract

The dynamic shear modulus of magnetosensitive (MS) natural rubber composites is experimentally studied, where influences of carbon black, plasticiser and iron particle concentrations are investigated at various dynamic shear strain amplitudes and external magnetic fields within the lower structure borne frequency range. The iron particles embedded in natural rubber are irregularly shaped and randomly distributed; the plasticisers simplify the iron particle blending process, while carbon black reduces the production costs and improves the mechanical properties. The results show that the relative MS effect on the shear modulus magnitude increases with increased plasticiser and iron particle concentration and decreases with increased carbon black concentration. Furthermore, their relative contributions are quantified. Consequently, the study provides a basis for optimising the composition of MS natural rubber to meet a variety of requirements, including those of vibration isolation, a promising application area for MS materials.     

炭黑用量对不同聚丁二烯橡胶性能的影响

研究了低顺式聚丁二烯橡胶（BR3505）、低门尼顺丁橡胶（BR9002）和普通顺丁橡胶（BR9000）的硫化参数、拉伸性能和动态压缩性能。结果表明，与普通顺丁橡胶相比，聚丁二烯橡胶中反式结构含量较多（BR3505）时，芟联密度、断裂伸长率、压缩生热和压缩永久变形大，而硫化速度慢很多；且分子量分布变宽（BR9002）使其硫化速度稍快、断裂伸长率大、压缩生热稍低，同时低炭黑用量时的拉伸强度和伸长率较高，但是炭黑可填充量降低。     

The order addition effect of carbon black/graphite on the electrical properties of rubber composites

Acrylonitrile‐butadiene rubber (NBR) filled with two types of fillers [high abrasion furnace carbon black (C), and graphite (G)] is made to find out the effect of order addition of C and G on the electrical conductivity of the composites. The temperature and frequency dependence of the (dc and ac) conductivity and dielectric constants have been measured. The values of the thermal expansion and thermal conduction coefficient of NBR rubber lead to the difference in I–V characteristics between CB‐ and G‐NBR rubber composites during the measurement. When graphite is first added to NBR, the electrical conductivity of (GC_20‐20) matrix is larger than that of the (CG_20‐20) matrix, whereas the carbon black is added first. At low temperature (T < 90°C), the higher values of the dielectric constant (ε′) for the sample GC_20‐20 compared with that of the CG_20‐20 sample is due to the conducting nature and structure of graphite, whereas the carbon shows less crystallinity and conductivity than graphite. Opposite behavior is noticed at temperature higher than 90°C. The dc conductivity of all composites increases with increasing temperature exhibiting a positive temperature coefficient of conductivity (PTCσ). The conductivity at high temperatures region is controlled by the thermal excitation transport mechanism, whereas at low temperatures region is dominated by tunneling process. The increase in the value of dielectric constant (ε′) with temperatures for the sample GC_20‐20 compared with the sample CG_20‐20 is due to the conducting nature and structure of graphite, and the carbon less crystalline than the graphite. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

不同硫化体系对天然橡胶的动静态性能的影响研究

分别制备了以炭黑和白炭黑为补强填料的不同硫化体系天然橡胶(NR)复合材料,研究硫化体系对NR胶料静态和动态性能的影响。结果表明:普通硫化体系硫化胶具有较高的交联密度、较好的物理性能和优异的耐磨性能;对于白炭黑补强体系,普通硫化体系硫化胶具有最低的滚动阻力;而对于炭黑补强体系,平衡硫化体系硫化胶具有最低的滚动阻力;胶料拉伸强度的增大有利于耐磨性的提高。     

Enhancing the electrical conductivity of carbon black/graphite nanoplatelets: Poly(ethylene‐butyl acrylate) composites by melt extrusion

The influence of processing parameters such as screw geometry, temperature profile, and screw speed on the electrical properties of hybrid composites consisting of graphite nanoplatelets and carbon black in ethyl butyl acrylate was studied. Two different screws were used to compound the hybrid composites at two different temperatures and two different screw speeds. A beneficial effect was noted with regard to the electrical properties when adding nanoplatelets to the filler system. The cause could be a synergistic effect due to the difference in particle shape of the two fillers. Lower percolation thresholds were obtained with the conventional screw due to less breakage of the graphite nanoplatelets compared to the barrier screw. No significant changes of the electrical properties were observed when changing the temperature profiles or the screw speeds. Furthermore, the melt viscosity of the compounds was not appreciably affected at the rather low filler contents used here. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42897.     

Effect of preextension on electrical conductivity and physicomechanical properties of butyl rubber (IIR) loaded with different types of carbon black

The effect of preextension on the variation of the electrical conductivity (σ) of butyl rubber (IIR) loaded with high abrasion furance (HAF) and fast extrusion furance (FEF) carbon black with carbon concentration have been investigated. The change in σ has been explained as a result of the interaction between carbon and rubber and the effect of the occluded rubber. The effect of preextension on the electrical resistivity (ρ) variation with strain has also been studied. The changes have been interpreted as being due to either breakdown or reagglomeration, depending on the concentration of carbon black.     

舰船用高性能密封橡胶研究(Ⅱ)纳米补强填料对氟橡胶硫化胶物理性能的影响

研究了普通炭黑、纳米炭黑、纳米白炭黑以及纳米炭黑／纳米白炭黑复合并用体系对舰船用氟橡胶硫化胶物理性能的影响。结果表明，纳米白炭黑／炭黑并用体系对提高补强效果具有协同作用，当纳米白炭黑在复合填充体系中质量分数在35％左右时氟硫化胶拉伸强度最大，断裂伸长率随填料用量增加而降低。纳米填料补强硫化胶不仅需要补强填料粒子与大分子之间有较强的结合力，而且需要补强填料粒子表面上的分子产生滑移。     

The effect of B‐doping on the electrical conductivity of polymer‐derived Si(B)OC ceramics

In this work the room temperature electrical conductivity of Si(B)OC glasses made via polymer pyrolysis at 1200°C and 1400°C (maximum temperature) and having different amount of boron was measured. When B content is increased from zero (pure SiOC glass) up to B/Si=0.5 the electrical conductivity increases in 2 orders of magnitude from 4.09±0.64×10^?5 up to 2.93±1.91×10^?3 with a corresponding decrease in the activation energy from about 1.08 to 0.51 eV. This results shows for the first time that the electrical conductivity of Si‐based polymer‐derived ceramics can be controlled by the amount of the doping element. The structure of the Si(B)OC glasses has been studied with different techniques including FT‐IR, XRD and Raman spectroscopy. The Raman study indicates that B partially substitutes C into the sp² C planes of the free carbon phase forming trigonal BC₃ units. Accordingly, the evolution of the electrical properties with the B content has been correlated with the corresponding structural evolution and a hypothesis is presented to rationalize the role of boron on the electrical conductivity of SiOBC glasses.     

Effect of surface oxidation of filler and silane coupling agent on the chemorheological behavior of epoxidized natural rubber filled with ISAF carbon black

On the basis of results of measurements of physical properties and solvent swelling of the extrudates, it has been observed that epoxidized natural rubber (ENR) interacts chemically with intermediate super abrasion furnace (ISAF) carbon black when the mix of the two was extruded at 130–160°C in a Monsanto Processability Tester (MPT). The extent of interaction between the rubber and filler depends on the following factors: extrusion time, carbon black loading, shear rate, and the extent of oxidation on the carbon black surface. Addition of the silane coupling agent, namely, N‐3‐(‐N‐vinyl benzyl amino) ethyl‐γ‐amino propyl trimethoxy silane monohydrochloride, enhances the rate of the interaction. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 557–563, 1999     

Influence of static strain on the dynamic mechanical properties of poly(diethyleneglycol isophthalate) networks

Time-dependent mechanical properties of small amplitude were superimposed on strained poly(diethyleneglycol isophthalate) networks. The tan δ loss peak associated with the glass-rubber relaxation shifts to lower temperatures as the static strain increases for values of the elongation ratio λ lower than 4, suggesting that volume effects overcome entropic effects in this region. However, for values λ > 4, the opposite occurs. The activation enthalpy is a linear function of the activation entropy, but the compensation law does not hold in the present system. Information on network topology is obtained by analysing the experimental results using theories that predict the value of the loss modulus as a function of the generalized momenta of the elastic chains.     

Synthesis,characterization, and electrical conductivity of polyaniline derivatives: Study with the metal ions Cu(II), Ni(II), and Co(II)

Poly(2-aminophenol), poly(3-aminophenol), poly(2-aminobenzyl alcohol), and poly(3-aminobenzyl alcohol) were synthesized by using ammonium persulphate as oxidizing reagent in HCl and HCl/CH₃CN mediums in the presence and absence of Cu(II), Ni(II), and Co(II) ions. The polymers were characterized by Fourier transform infrared spectroscopy, ultraviolet-vis spectroscopy, thermal analysis, and electrical conductivity measurements. The substituent in 2- and 3-positions decreases the yield regarding aniline. Poly(2-,3-aminobenzyl alcohol) are obtained in an intermediate redox state and polymerized as aniline. On the contrary, poly(aminophenols) are obtained as overoxidated structures. The presence of metal ion produces an important increase of the polymerization yield. The metal cations would act as oxidizing agents. The incorporation of these metal ions depends on the reaction medium. The metal ion increases the thermal stability. Poly(2-aminobenzyl alcohol)-copper ions also increases the electrical conductivity. The electrical conductivity is higher by acid doping than by the incorporation of metal ions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 330–337, 2001