The partial replacement of silica or calcium carbonate by halloysite nanotubes as fillers in ethylene propylene diene monomer composites

The effect of partial replacement of silica or calcium carbonate (CaCO₃) by halloysite nanotubes (HNTs) on the curing behavior, tensile properties, dynamic mechanical properties, and morphological characteristics of ethylene propylene diene monomer (EPDM) composites was studied. Five different compositions of EPDM/Silica/HNT and EPDM/CaCO₃/HNT compounds (i.e. 100/30/0, 100/25/5, 100/15/15, 100/5/25, and 100/0/30 parts per hundred rubber (phr)) were prepared on a two‐roll mill. The results indicated that the replacement of CaCO₃ by HNTs increased the tensile strength, elongation at break (E_b), and tensile modulus of composites from 0 to 30 phr of HNTs whereas for silica, the maximum tensile strength and E_b occurred at 5 phr loading of HNTs with an enhanced stress at 300% elongation (M300). The curing results show that, with replacement of silica or CaCO₃ by HNTs, the cure time (t₉₀) and cure rate (CRI) were decreased and increased, respectively. Scanning electron microscopy investigation confirmed that co‐incorporation of 5 phr of HNTs with silica would improve the dispersion of silica and enhanced the interactions between fillers and EPDM matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The Properties of Acrylonitrile-Butadiene Rubber (NBR) Composite with Halloysite Nanotubes (HNTs) and Silica or Carbon Black

The properties of acrylonitrile-butadiene rubber (NBR) composites were studied at five different compositions of NBR/HNTs/Silica or NBR/HNTs/CB (i.e., 100/5/0, 100/4/1, 100/3/2, 100/2/3, 100/0/5 parts per hundred rubber (phr)). The tensile strength and modulus (M100) of both composites decreased, whereas elongation at break increased and maximum torque with increasing the silica or carbon black content. However, both composites show opposite trends for cure time and scorch time, where NBR/HNTs/Silica composite exhibited an increasing trend, while NBR/HNTs/CB composite shows the decreasing trend. The rubber-filler interaction studies showed that carbon black is a more reinforcing filler than silica.     

Design and analysis of single-factor experiments: Analysis of variance of the effect of rice husk ash and commercial fillers in NR compounds

Summary White rice husk ash (WRHA) and black rice husk ash (BRHA) were incorporated into natural rubber (NR) using a laboratory-sized two-roll mill. A conventional vulcanization system was used for curing and physical tests of the NR vulcanized involved determining of tensile and tear resistances. For comparison purposes, precipitated silica (Zeosil-175) and carbon black (N774) were used too. Using the analysis of variance of single-factor experiments, it can be concluded that: BRHA is non-reinforcing filler and its use is limited to 20 phr; WRHA is semi-reinforcing filler and the variation of filler loading (0 up to 50 phr) causes the maximum variation upon tensile strength of NR compounds; and, that although carbon black and silica are reinforcing fillers, a real reinforcement is reached up to 20 phr for tensile strength.     

Mechanical and dynamic mechanical properties of rice husk ash–filled natural rubber compounds

A laboratory‐sized two‐roll mill was used to incorporate rice husk ash into natural rubber (NR). A conventional vulcanization system was used for curing and cure studies were carried out on a Monsanto rheometer. Physical testing of the NR vulcanizates involved determining tensile and tear resistances and hardness. Swelling behavior of NR compounds and scanning electron microscopy were used to investigate the interaction between rice husk ash and natural rubber. Also, dynamical mechanical thermal analysis was used to assess filler–rubber interactions in terms of storage modulus (E′) and loss tangent (tan δ). For comparison purposes, two commercial fillers, precipitated silica (Zeosil‐175) and carbon black (N774), were also used. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2331–2346, 2002     

Properties of natural rubber composites reinforced with silica or carbon black: influence of cure accelerator content and filler dispersion

Filler dispersion is a critical factor in determining the properties of filled rubber composites. Silica has a high density of silanol groups on the surface, which lead to strong filler–filler interactions and a poor filler dispersions. A cure accelerator, N‐tert‐butyl‐2‐benzothiazole sulfenamide (TBBS), was found to improve filler dispersion in silica‐filled natural rubber (NR) compounds. For the silica‐filled NR compounds without the silane coupling agent, the reversion ratio generally increased with increase in TBBS content, whereas those of the silica‐filled NR compounds containing the silane coupling agent and carbon black‐filled NR compounds decreased linearly. The tensile strength of the silica‐filled NR vulcanizate without the silane coupling agent increased as the TBBS content increased, whereas carbon black‐filled samples did not show a specific trend. The experimental results were explained by TBBS adsorption on the silica surface and the improvement of silica dispersion with the aid of TBBS. Copyright © 2003 Society of Chemical Industry     

Synergistic effect of plasma‐modified halloysite nanotubes and carbon black in natural rubber—butadiene rubber blend

Halloysite nanotubes (HNTs) were investigated concerning their suitability for rubber reinforcement. As they have geometrical similarity with carbon nanotubes, they were expected to impart a significant reinforcement effect on the rubber compounds but the dispersion of the nanofillers is difficult. In this work, HNTs were surface‐modified by plasma polymerization to change their surface polarity and chemistry and used in a natural rubber/butadiene rubber blend in the presence of carbon black. The aim of the treatment was to improve the rubber–filler interaction and the dispersion of the fillers. A thiophene modification of HNTs improved stress–strain properties more than a pyrrole treatment. The surface modification resulted in a higher bound rubber content and lower Payne effect indicating better filler–polymer interaction. Scanning electron microscopy measurements showed an increased compatibility of elastomers and fillers. As visualized by transmission electron microscopy, the thiophene‐modified HNTs formed a special type of clusters with carbon black particles, which was ultimately reflected in the final mechanical properties of the nanocomposites. The addition of HNTs increased loss angle. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

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     

Application of lime kiln dust as a filler in the natural rubber industry

Lime kiln dust (LKD) obtained from kraft chemical recovery systems by conversion of calcium carbonate (CaCO₃) back into calcium oxide (CaO) for reuse in the causticizing process, is mainly composed of CaCO₃. A two‐stage conventional mixing procedure was used to incorporate LKD into natural rubber (NR). For comparison purposes, four commercial fillers, stearic acid coated CaCO₃, ground CaCO₃, silica, and carbon black, were also used. The effect of these fillers on the curing characteristics and mechanical properties of NR materials at various loadings ranging from 0 to 60 phr were studied. The results indicate that the use of LKD filler resulted in a lower Mooney viscosity and shorter curing time in the NR materials. The incorporation of LKD into NR improved the Young's modulus and hardness but decreased the tensile strength and tear strength. However, LKD was better in processability than the commercial fillers. Scanning electron micrographs revealed that the morphology of the rubbers filled with reinforcing fillers, such as silica and carbon black, was finer and more homogeneous compared to the those of the rubbers filled with LKD and commercial CaCO₃. The dispersion of LKD and commercial CaCO₃ fillers in the rubber matrix was discontinuous, which in turn, generated a weak structure compared with the reinforcing fillers. According to these observations, LKD could be used as a cheaper filler for NR materials where improved mechanical properties are not critical. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A comparative study of aging characteristics and thermal stability of oil palm ash,silica, and carbon black filled natural rubber vulcanizates

Filler‐filled natural rubber (NR) vulcanizates were prepared by conventional laboratory‐sized two roll mills and cured using sulfuric system. The effect of thermal aging on physical properties and thermogravimetric analysis (TGA) of oil palm ash (OPA) and commercial fillers (i.e., silica vulkasil C and carbon black N330)‐filled NR vulcanizates at respective optimum loading and equal loading were studied. Before aging, the OPA‐filled vulcanizates showed comparable optimum strength as carbon black‐filled vulcanizates. The hardening of aged filler‐filled NR vulcanizates happened after aging, thereby tensile strength and elongation at break reduced while the modulus increased. Fifty phr carbon black‐filled vulcanizates showed better retention in tensile properties as compared to silica (10 phr) and OPA (1 phr). This was attributed to the addition of different filler loading and this finding was further explained when equal loading of filler‐filled vulcanizates was studied. Fourier transform infra‐red analysis showed chemical structure had changed and tensile fractured surface exhibited smooth appearance due to the deterioration in tensile properties after aging. TGA also denoted the thermal stability was depending on the amount of filler loading. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4474–4481, 2013     

氯丁橡胶244与天然胶共混性能研究

摘要:本文主要研究了硫化体系和补强体系对氯丁橡胶与天然胶共混时性能的影响,其中主要涉及到氧化锌、氧化镁、普通硫磺、DM作为硫化体系以及碳黑N550和白炭黑作为补强体系时对共混胶料物理机械性能的影响。经过研究发现：氧化锌：氧化镁：普通硫磺：DM硫化促进剂=6：3：5：0.3时,扯断强度能达到：23.18MPa,硫磺对硫化胶料绍尔硬度的影响最大,硫化时间为60min时得到的物理机械性能最好,碳黑N550为40份、白炭黑为20份时,硫化胶料的物理机械性能最好。     

炭黑/煤矸石/碳纳米管复合填料体系对天然橡胶性能的影响研究*

利用硝酸氧化法对碳纳米管(CNTs)进行纯化,并用环氧天然橡胶(ENR)进行改性处理。结合胶质量分数测定结果表明, ENR用量15%(质量)时效果最佳。采用胶乳凝聚法制备CNTs/天然橡胶(NR)母料。煤矸石粉(CG)经高温煅烧和表面改性处理。 将CNTs/天然橡胶(NR)母料、CG和炭黑(CB)通过机械混炼法与天然橡胶及配合剂混合,制备CB/CG/CNTs/NR复合材料,并对复合材料进行硫化特性及物理机械性能。结果表明： CNTs延迟硫化效应明显;相比炭黑,CG对硫化具有促进作用。硫化特性和甲苯溶胀法测定结果表明,在填料份数相同的条件下,单独由CB填充的NR有最大的交联密度,CNTs对交联密度影响不明显。物理机械性能测试结果表明,当CG：CB：CNTs=17.5:16.5:1(Phr)时,NR硫化胶的300%定伸应力和扯断伸长率明显高于单独由CB填充NR,而拉伸强度与之接近,复合填料样填充NR具有较好的综合性能。扫描电镜测试结果表明,复合填料在NR基体中分布均匀。     

Filler–rubber interactions in α_cellulose‐filled styrene butadiene rubber composites

In this study, the interactions between rubber and fillers in α_cellulose‐filled styrene butadiene rubber (SBR) composites were investigated. The results obtained from the tensile and tear strength, abrasion resistance, and hardness indicate that addition of 5‐phr α_cellulose into compound not only does not affect rubber–carbon black bond but improves the mentioned physicomechanical properties. In this study, the type of carbon black was changed from N 330 to N 550. The main purpose of this investigation was to observe the possible changes in physicomechanical properties due to this change. Obtained results show that overall observation of the trends of results do not change with type of carbon black. It can be concluded that the presence of α_cellulose does not have significant influence on the performance of carbon black in the compounds used. POLYM. COMPOS., 28:748–754, 2007. © 2007 Society of Plastics Engineers     

A New Approach to Improved Properties of Rubber Vulcanizates Containing White Molybdates

Incorporation of fillers in rubber results in a profound effect on rheological and mechanical properties of the formed composites. Fillers are customarily classified into organic and inorganic. The latter class includes calcium carbonate, talc, barium sulfate, kaolin, silica, etc. Molybdates are inorganic, nontoxic white pigments combined with reasonable pricing range and controlled solubility. The purpose of this study was to employ white molybdates and study their role as reinforcing fillers that can replace traditional carbon black, or semi-reinforcing furnance black (SRF), with both natural rubber (NR) and a blend of natural rubber-styrene butadiene rubber (NR-SBR), to show the modification of rheometric characteristics, tensile strength, strain at break, hardness, Young's modulus, swelling in toluene, thermal oxidative aging, and calculation of the rubber-filler interaction after the addition of such fillers.     

Effect of carbon black on properties of rubber nanocomposites

Polymer based nanocomposites were prepared using brominated poly(isobutylene‐co‐paramethylstyrene) (BIMS) rubber and octadecyl amine modified montmorillonite nanoclay. The effect of nature and loading of carbon black on these nanocomposites and the control BIMS was investigated thoroughly using X‐ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), and mechanical properties. The addition of 4 parts of the modified nanoclay to 20 phr N550 carbon black filled samples increased the tensile strength by 53%. Out of the three different grades of carbon black (N330, N550, and N660), N550 showed the best effect of nanoclay. Optimum results were obtained with the 20 phr filler loading. For comparison, china clay and silica at the same loading were used. Fifty‐six and 46% improvements in tensile strength were achieved with 4 parts of nanoclay added to the silica and the china clay filled samples, respectively. N330 carbon black (20 parts) filled styrene butadiene rubber (SBR) based nanocomposite registered 20% higher tensile strength with 4 parts of the modified nanoclay. In all the above carbon black filled nanocomposites, the modulus was improved in the range of 30 to 125%. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 443–451, 2005     

KH550对炭黑填充NR性能的影响研究

本文考察了不同用量KH550对炭黑填充NR的硫化特性、动态性能及物理机械性能的影响。结果表明,KH550的加入降低了焦烧时间和正硫化时间,交联程度有明显提高;KH550添加量为2份时硬度及拉伸强度达到最大值,拉断伸长率有所降低,回弹及压缩永久变形性能有明显改善;KH550的加入有效降低炭黑的payne效应,提高胶料的交联密度及炭黑的分散性,胶料损耗因子及动态生热明显降低,胶料动态性能明显改善。     

Safe amine based zinc dithiocarbamates for the vulcanization of carbon black reinforced natural rubber

Binary combination of three safe amine based synthesized zinc dithiocarbamates (ZDC), namely zinc (N‐benzyl piperazino) dithiocarbamate (ZBPDC), zinc (N‐ethyl piperazino) dithiocarbamate (ZEPDC), and zinc (N‐phenyl piperazino) dithiocarbamate (ZPPDC) with mercapto benzothiazole disulfide (MBTS) as an effective accelerator system for the vulcanization of carbon black (N330, N550, and N774) filled natural rubber (NR) composites are studied. A comparison between the safe amine based zinc dithiocarbamates with the unsafe zinc dimethyl dithiocarbamate (ZDMC) in the light of mechanical and aging resistance behavior, introduces the non carcinogenic rubber additives in the filled vulcanization of rubber. Both accelerator and filler have the major importance for improving the mechanical as well as aging resistance behavior of the resultant vulcanizate. Variation in the filler and also filler to oil ratio are done to optimize the mechanical properties. SEM studies of different types of filler with different amounts show that N330 at 30 phr loading composites forms more homogeneity and less aggregated structures. Natural rubber systems with N330 carbon black show the best results with respect to tensile strength, but after the aging N774 carbon black filled system indicates better retention in the tensile strength. ZPPDC‐MBTS accelerated vulcanizate shows the better age resistance behavior than ZDMC‐MBTS accelerated vulcanizate. From both the points of age resistance and mechanical properties, ZBPDC‐MBTS accelerator system is the suitable substitute for ZDMC‐MBTS accelerated system in the filled vulcanization of natural rubber composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39988.     

The effect of coupling agent and chemical treatment on rice husk ash‐ filled natural rubber composites

Rice husk ash was incorporated into natural rubber (NR) using a laboratory size two‐roll mill. Curing using a conventional vulcanization system (CV) was chosen, and cure studies were carried out on a Monsanto rheometer. Physical testing of the NR vulcanizates involved the determination of tensile, tear, and abrasion resistances, and hardness. Fourier transform infrared spectroscopy (FTIR) analysis was done to verify the presence of the characteristic functional groups of precipitated silica in MHA (milled husk ash) and THA (treated husk ash). The effect of the coupling agent, bis(3‐triethoxysilylpropyl)‐tetrasulfane (Si‐69), on the curing and physical properties of the vulcanizates was investigated. A chemical treatment on a rice husk ash was done, and the effects of this procedure are also reported. For comparison, two commercial fillers, precipitated silica (Zeosil‐175) and carbon black (N774), were also used. Although the presence of the silane coupling agent had not brought the expected increase in properties, treated husk ash showed exceptional performance in terms of tensile strength and abrasion resistance of the filled vulcanizates. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1019–1027, 2000     

硫化温度对NR高温下拉伸／撕裂性能的影响

采用74个不同的硫化温度硫化NR,并测试其高温下拉伸／撕裂性能、交联密度和炭黑分散情况。结果表明：随测试温度的提高,NR的拉伸强度和撕裂强度均呈现逐渐下降的趋势,且在同-测试温度下,硫化胶的拉伸强度随着硫化温度的升高而逐渐降低;在测试温度小于100℃时,硫化胶的撕裂强度随硫化温度的升高而逐渐升高,测试温度大于100℃时,硫化胶的撕裂强度随硫化温度的升高而逐渐降低。     

A Review on Hybrid Fillers in Rubber Composites

This review article is aimed at reporting the recent development of hybrid fillers used in vulcanized rubber. This review will consider the synergistic effect of rubber hybrid composites that consist exclusively of conventional fillers; carbon black and/or silica as the primary filler, which are combined with secondary fillers from various sources. The discussions are mainly focused on the analyses and comparisons of the curing characteristics, morphology, and mechanical properties of the rubber composite-filled hybrid fillers. The compatibility and the existence of synergistic effects between the different types of fillers show the potential for development and application in rubber industries.     

Influence of bound polymer on cure characteristics of natural rubber compounds reinforced with different types of carbon blacks

Rubber compounds are reinforced with fillers such as carbon black and silica. The cure characteristics of a filled rubber compound vary with the filler type and content. The influence of the type of carbon black on the cure characteristics of carbon black filled natural rubber compounds is investigated using two types of carbon black (N220 and N550), which are different in primary size and structure. The cure time and cure rate become faster as the carbon black content increases. The crosslink density also increases and reversion resistance is improved with the increase of carbon black content. The cure time and cure rate of the compound filled with N550 are faster than those of the compound filled with N220 at the same level of bound rubber content. In addition, higher crosslink density is also observed in the compound filled with N550 compared to that of the compound filled with N220 at the same level of bound rubber content. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2282–2289, 2005