Effect of the processing conditions and the addition of trans-polyoctenylene rubber on the properties of natural rubber/styrene–butadiene rubber blends

In this study, the influence of the processing conditions and the addition of trans-polyoctenylene rubber (TOR) on Mooney viscosity, tensile properties, hardness, tearing resistance, and resilience of natural rubber/styrene–butadiene rubber blends was investigated. The results obtained are explained in light of dynamic mechanical and morphological analyses. Increasing processing time produced a finer blend morphology, which resulted in an improvement in the mechanical properties. The addition of TOR involved an increase in hardness, a decrease in tear resistance, and no effect on the resilience. It resulted in a large decrease in the Mooney viscosity and a slight decrease in the tensile properties if the components of the compounds were not properly mixed. The results indicate that TOR acted more as a plasticizer than a compatibilizer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

固相法改性淀粉／炭黑／丁苯橡胶复合材料的制备与性能研究

采用固相法制备了淀粉接枝马来酸酐（MAH）和丙烯酸丁酯（BA）的共聚物Starch-gMAH／BA（SMB）。采用机械共混法用15phr的改性淀粉（SMB）代替等量的炭黑（CB）,制备了改性淀粉／炭黑／丁苯橡胶复合材料（SMt3／CB／SBR）,研究了复合材料的力学性能、热氧老化性能、动态力学性能以及微观形态。结果表明,SMB／CB／SBR复合材料的力学性能优于未改性淀粉／CB／SBR复合材料,拉伸强度及扯断伸长率等性能优于SBR／CB复合材料;且SMB／CB／SBR复合材料具有更好的耐热氧老化性能;与SBR／CB复合材料相比,SMB／CB／SBR复合材料具有更低的滚动阻力;微观形态显示,淀粉经改性后粒子尺寸减小,在SBR基体中的分散性得到改善,与SBR基体的相容性得到提高。     

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.     

溶聚丁苯橡胶/炭黑/短纤维多相复合材料的动态力学性能

研究了短纤维用量和黏合水平、测试温度及频率对溶聚丁苯橡胶（SSBR）／炭黑／短纤维复合材料（SFRC）动态力学性能的影响。结果表明,SFRC的储能模量（E’）随短纤维用量的增加而增大;填充预处理短纤维的SFRC的E’大于填充同种未处理短纤维的SFRC,损耗因子（tanδ）则是后者大于前者（填充20份尼龙短纤维的SFRC除外）。与相同填充量的纯炭黑硫化胶相比,短纤维部分取代炭黑后,硫化胶在大于15℃时的E’增大（填充未处理聚酯短纤维的SFRC除外）,tanδ减小;SFRC的E’和tanδ随频率的增加而增大,但频率为50～100Hz时,随着温度的升高,短纤维用量越高,SFRC的E’减小,且E。和tanδ受频率的影响越小。     

化学改性脱硫灰取代部分炭黑制备环保型丁苯橡胶及其性能

用硅烷偶联剂Si69和KH550对脱硫灰进行化学改性,用改性脱硫灰取代部分炭黑与丁苯橡胶复合,制备环保型丁苯橡胶,对其进行了表征,采用均匀设计结合BP神经网络建立模型优化工艺参数. 结果表明,最优制备工艺参数为Si69和KH550用量分别为4.3wt%和3.8wt%、无水乙醇用量22.1wt%、搅拌速度705 r/min、反应温度82℃,该条件下所制环保型丁苯橡胶的力学性能为拉伸强度19.64 MPa、撕裂强度44.96 kN/m、邵氏A硬度66. 实验结果与模型预测值吻合较好,相对误差为3.03%~2.65%.     

Nanoclay distribution and its influence on the mechanical properties of rubber blends

The distribution of modified and unmodified nanoclays inside the rubber phases of immiscible rubber–rubber blends composed of nonpolar–polar natural rubber (NR)/epoxidized natural rubber (ENR) and nonpolar–nonpolar NR/polybutadiene rubber (BR) was investigated for the first time. The distribution of clays at various loadings in the blends was calculated from the viscoelastic properties of the blends. For example, in the 50 : 50 NR/ENR blend, 42% Cloisite 30B migrated to the NR phase, and 58% went to the ENR phase. However, in the same blend, only 7% Cloisite Na⁺ was found in the NR phase, and 93% was found in the ENR phase. Again, in the 50 : 50 NR/BR blends, the NR phase contained 85% Cloisite 30B, whereas 55% Cloisite Na⁺ migrated to the NR phase. All these observations were explained with the help of viscosity, X‐ray diffraction, and morphology analyses. The effect of the distribution of the clay on the mechanical properties was also discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Dynamic study of free volume properties in polyethylene/styrene butadiene rubber blends by positron annihilation lifetime method

Positronium (Ps) formation in low and high‐density polyethylene (LDPE and HDPE) and styrene butadiene rubber (SBR), as well as in their blends (LDPE/SBR: 50/50 and HDPE/SBR: 50/50) has been investigated by positron annihilation lifetime (PAL) measurements as a function of low temperature (100–300 K). The glass transition temperature (T_g) for the initial polymers and their blends are determined by ortho‐positronium (o‐Ps) lifetime, τ₃ versus temperature as well as by differential scanning calorimetry (DSC) measurements. The temperature dependence of nanoscale free volume size shows similar trend for all the investigated samples indicating an abrupt change at T_g, which is found to be higher for SBR sample characterized by its high chain mobility. In addition, The T_g values deduced from PAL measurements are compared with the corresponding data deduced from DSC. The variation of o‐Ps formation probability I₃ versus temperature for polyethylene and their blends were interpreted in the frame work of spur reaction model of Ps formation. On the other hand, the lifetime coefficient below and above T_g is found to be one order of magnitude larger than the linear expansion coefficient. This constitutes evidence that Ps is only probing free volumes. The results obtained from change in free volume–hole distribution with temperature reflect both thermal expansion and increase in free volume–hole size with the rise in temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

甲基丙烯酸固态原位接枝改性炭黑对天然橡胶和顺丁橡胶性能的影响

考察了固态原位接枝改性制备的甲基丙烯酸接枝改性炭黑对天然橡胶(NR)和顺丁橡胶。(BR)静态力学性能、动态力学性能的影响。结果表明。甲基丙烯酸改性炭黑比普通商品炭黑填充的NR硫化胶具有更好的静态力学性能;甲基丙烯酸改性炭黑曼有利于降低NR和BR硫化胶的滚动阻力。同时,有利于提高NR硫化胶的抗湿滑性。     

溶聚丁苯橡胶/炭黑/短纤维复合材料的取向结构与力学性能

研究了溶聚丁苯橡胶(SSBR)／炭黑／短纤维复合材料(SFRC)的力学性能和短纤维在橡胶中的取向度及其黏合效果,分析了短纤维的黏合作用对复合材料应力．应变形为的影响。结果表明,短纤维的加入显著提高了SFRC的撕裂强度、10％定伸应力及邵尔A型硬度;短纤维用量小于30份时。2种预处理短纤维的取向度呈增长趋势,且尼龙短纤维的取向度明显高于聚酯短纤维;SFRC在平行方向上有不同程度的屈服现象,且添加聚酯短纤维的SFRC屈服应变及应力值小于添加尼龙短纤维的SFRC。SFRC在垂直方向没有应力屈服现象;预处理短纤维与橡胶的黏合效果优于未处理短纤维。     

Natural rubber–styrene butadiene rubber latex blends: Time-dependent rheological behavior and film formation

This article focuses mainly on the effect of maturation time on the rheological behavior of unvulcanized natural rubber (NR)–styrene butadiene rubber (SBR) latex blends. Viscosity shows a composition-dependent behavior with maturation time. It was found that there is a marginal decrease in viscosity for all the systems with maturation time except for the 70/30 NR–SBR blend. In this blend, there is a sharp decrease in viscosity with maturation time. This is associated with the exchange of stabilizers with one another until an equilibrium is reached; that is, all the particles of the blend are stabilized with random mixture of stabilizers. The structural build up observed in 70/30 NR–SBR blend was found to be diminished as the maturation time increases. At equilibrium, there is no further exchange of stabilizers. The behavior of this blend has been explained with the help of a schematic model. The effects of blend ratio and surface active agents on the viscosity were also studied. In addition, the time-dependent flow behavior of prevulcanized latex blends was evaluated as a function of vulcanizing systems and prevulcanization time. There is a regular increase in viscosity with prevulcanization time. However, after 3 h, the viscosity of almost all blends levels off, indicating that the curing reaction is complete within this time. Finally, the morphological changes occurred during film formation of the blends were studied using scanning electron microscopy. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1473–1483, 1998     

Evaluation of physical and dielectric properties of chloroprene and styrene butadiene rubber blends

The influence of bis(diisopropyl) thiophosphoryl disulfide, a multifunctional rubber additive, on the curing characteristics and physical properties of polychloroprene rubber and styrene butadiene rubber blends was studied. It is evident from the study that covulcanization of SBR and CR following a two‐stage process leads to the development of improved physical properties of the vulcanizates. Dielectric and scanning electron microscopy study supports the occurrence of coherence of the dissimilar rubber blends. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1492–1504, 2005     

Study of butadiene rubber mastication and mixing with carbon black

A thermomechanical method was applied to study the topological and molecular structure of SKD butadiene rubber masticated and mixed with carbon black. Triblock structure (two amorphous blocks and one a pseudocrystalline structure) of a studied raw rubber and rubber compound networks were found. A ratio of these morphology structures changes during mastication. After mastication, a low‐temperature block has two glass transition temperatures that shows its more complex structure than that in raw rubber. This shows deep transformations taking place during the mastication process. Despite applying high shear forces and heating during mixing with carbon black in a filled BR compound, we present three structures characteristic for BR. However, introduction of carbon black changes the topological structure of polybutadiene. A part of both amorphous blocks grows. A part of a crystalline structure lowers from 88% after 2.5 min of mixing to 54% after 20 min of compounding. The molecular weight distribution of the chains between the junctions of the network and parts of low‐temperature and high‐temperature amorphous blocks, and pseudocrystalline structures in architecture of the rubber network were also calculated. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 729–737, 1999     

Mechanical and aging properties of cross‐linked ethylene propylene diene rubber / styrene butadiene rubber blends

The mechanical properties and aging characteristics of blends of ethylene propylene diene monomer (EPDM) rubber and styrene butadiene rubber (SBR) were investigated with special reference to the effect of blend ratio and cross‐linking systems. Among the blends, the one with 80/20 EPDM/SBR has been found to exhibit the highest tensile, tear, and abrasion properties at ambient temperature. The observed changes in the mechanical properties of the blends have been correlated with the phase morphology, as attested by scanning electron micrographs (SEMs). The effects of three different cure systems, namely, sulfur (S), dicumyl peroxide (DCP), and a mixed system consisting of sulfur and peroxide (mixed) on the blend properties also were studied. The stress‐strain behavior, tensile strength, elongation at break, and tear strength of the blends were found to be better for the mixed system. The influence of fillers such as high‐abrasion furnace (HAF) black, general‐purpose furnace (GPF) black, silica, and clay on the mechanical properties of 90/10 EPDM/SBR blend was examined. The ozone and water aging studies also were conducted on the sulfur cured blends, to supplement the results from the mechanical properties investigation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2606–2621, 2004     

Thermal degradation and ageing behavior of microcomposites of natural rubber,carboxylated styrene butadiene rubber latices,and their blends

The effect of microfillers on the thermal stability of natural rubber (NR), carboxylated styrene butadiene rubber (XSBR) latices, and their 70/30 NR/XSBR blend were studied using thermogravimetric method. Microcomposites of XSBR and their blend were found to be thermally more stable than unfilled samples. The activation energy needed for the degradation of polymer chain was calculated from Coats‐Redfern plot. Activation energy needed for the thermal degradation of filled samples was higher than unfilled system. It indicated the improved thermal stability of the filled samples. The ageing resistance of the micro‐filled samples was evaluated from the mechanical properties of aged samples. The thermal ageing was carried out by keeping the samples in hot air oven for 7 days at 70°C. The mechanical properties such as tensile strength, modulus at 300% elongation, and strain at break were computed. As compared to unfilled samples, micron‐sized fillers reinforced systems exhibited higher ageing resistance. Finally, an investigation was made on the influence of ion‐beam irradiation on microcomposites of NR, XSBR latices, and their 70/30 blend systems using ²⁸Si⁸⁺ performed at 100 MeV. The surface changes of the samples after irradiation were analyzed using X‐ray photoelectron spectroscopy. The results of XPS measurements revealed that the host elements were redistributed without any change in binding energies of C_1s, O_1s, and Si_2p. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

炭黑补强异戊橡胶和天然橡胶性能之对比研究

用填充炭黑的异戊橡胶（IR）和天然橡胶（NR）分别研究其硫化特性、力学性能、热空气老化性能和动态力学性能。结果表明,异戊橡胶比天然橡胶的硫化速度慢,焦烧时间长。随着炭黑用量的增多,IR和NR的300％定伸应力增大,拉伸强度和拉断伸长率都下降,撕裂强度出现了峰值。炭黑用量增加到40份时,IR的拉伸强度下降最缓慢,耐老化性能最好;而NR随炭黑用量增加,其拉伸强度下降加快,耐老化性能变差。0℃时IR的损耗因子大于NR的损耗因子;60℃时,IR的损耗因子小于NR的损耗因子。     

改性炭黑对天然橡胶/顺丁橡胶并用胶性能的影响

采用3种方法对传统炭黑进行表面改性,考察了改性前后炭黑表面形貌及结构的变化,并采用改性炭黑填充天然橡胶（NR）/顺丁橡胶（BR）并用胶,考察了改性炭黑对并用胶力学性能、硫化特性及动态力学性能等的影响。结果表明,与未改性炭黑相比,细化粒径、调高pH值及木质素改性处理后,炭黑表面的粗糙程度增加;且细化改性炭黑具有更高的比表面积,调高pH值改性炭黑具有更多疏松的二次结构,木质素改性炭黑粒径略有增加。对于炭黑填充NR/BR,用细化粒径及调高pH值方法处理的炭黑进行填充,NR/BR硫化胶的力学性能、耐磨性能及抗湿滑性均得到明显改善,但硫化延迟效应明显;木质素改性后,炭黑填充胶的力学性能、耐磨性能均出现不同程度的降低。     

Carbon black filled powdered natural rubber: Preparation,particle size distribution,mechanical properties,and structures

Carbon black (HAF) filled powdered natural rubber (P(NR/HAF)) was prepared and the particle size distribution, mechanical properties, and micromorphology of P(NR/HAF) were studied. A carbon black–rubber latex coagulation method was developed for preparing carbon black filled free‐flowing, noncontact staining NR powders with particle diameter less than 0.9 mm. A powdering mechanism model was put forward to describe the powdering process, which shows that the key technical points consist in the surfactant with good emulsification properties and the polymer coating resin with good film forming properties. SEM analysis shows that carbon black and rubber matrix have formed a macroscopic homogenization in the P(NR/HAF) particles without contact staining, and carbon black particles are well dispersed in rubber matrix with diameter of about 50–150 nm. P(NR/HAF) vulcanizate showed better mechanical properties than bale natural rubber/carbon black blends (NR/HAF) and simple NR latex/carbon black blends (NRL/HAF), which depends primarily upon the absence of free carbon black, the fine dispersion of filler on the rubber matrix, and the better interaction between carbon black and rubber matrix due to the proper preparation condition of noncontact staining carbon black filled powdered NR. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1763–1774, 2006     

炭黑中杂质含量对胶料性能的影响

研究了炭黑中的筛余物、灰分和水分质量分数对胶料性能的影响。结果表明,杂质质量分数保持在较低范围时,对炭黑胶料在拉伸强度、扯断伸长第及３００％定伸应力影响较小,但对耐屈挠龟裂性能的显著影响;炭黑中水分质量分数超出一定范围时,影响胶料的焦烧时间及硫化速度。     

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。