Waste cement dusts as activating agents for rubber compounds

The possibility of substitution of an expensive zinc oxide by the waste cement dusts used in the character of the rubber compound activators were shown. The chemical constitution and the physico-chemical properties of the used cement dusts were investigated, as well as the physico-mechanical parameters of the vulcanizates which had these cement dusts, were determined. Some good strength properties were found for the vulcanizates which had the cement dusts. The results show a real possibility of the elimination of zinc oxide as an activating agent of the rubber compounds, and of substitution of one of the waste cement dusts.     

Fly ash particles and precipitated silica as fillers in rubbers. I. Untreated fillers in natural rubber and styrene–butadiene rubber compounds

In this study, we investigated the effects of untreated precipitated silica (PSi) and fly ash silica (FASi) as fillers on the properties of natural rubber (NR) and styrene–butadiene rubber (SBR) compounds. The cure characteristics and the final properties of the NR and SBR compounds were considered separately and comparatively with regard to the effect of the loading of the fillers, which ranged from 0 to 80 phr. In the NR system, the cure time and minimum and maximum torques of the NR compounds progressively increased at PSi loadings of 30–75 phr. A relatively low cure time and low viscosity of the NR compounds were achieved throughout the FASi loadings used. The vulcanizate properties of the FASi‐filled vulcanizates appeared to be very similar to those of the PSi‐filled vulcanizates at silica contents of 0–30 phr. Above these concentrations, the properties of the PSi‐filled vulcanizates improved, whereas those of the FASi‐filled compounds remained the same. In the SBR system, the changing trends of all of the properties of the filled SBR vulcanizates were very similar to those of the filled NR vulcanizates, except for the tensile and tear strengths. For a given rubber matrix and silica content, the discrepancies in the results between PSi and FASi were associated with filler–filler interactions, filler particle size, and the amount of nonrubber in the vulcanizates. With the effect of the FASi particles on the mechanical properties of the NR and SBR vulcanizates considered, we recommend fly ash particles as a filler in NR at silica concentrations of 0–30 phr but not in SBR systems, except when improvement in the tensile and tear properties is required. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2119–2130, 2004     

不同补强体系胶料疲劳断裂性能的研究

应用断裂力学理论定性和定量地研究了ＮＲ和ＢＲ／ＮＲ（并用比为７０／３０）胶料在添加不同炭黑补强体系（ＨＡＦ,ＩＳＡＦ和ＳＡＦ）时的动态疲劳过程。用分子论观战描述了胶料的动态疲劳过程,结合断裂特征参数β和Ｃ０对Ｓ－Ｎ曲线进行了分析比较。结果表明,在添加ＨＡＦ,ＩＳＡＦ和ＳＡＦ这３种补强体系的胶料中,随着补强体系粒径的减小,其抗裂纹扩展性变差,但胶料内部潜在缺陷减少。     

Hybrid fillers of lignin and carbon black for lowering of viscoelastic loss in rubber compounds

This study investigates novel hybrid fillers for lowering of viscoelastic dissipation in rubber compounds by exploiting non-covalent interactions between lignin and carbon black (CB). Lignin is naturally occurring three-dimensional amorphous polymer consisting of phenyl propane units with hydroxyl, methoxy, and carbonyl substitutions and is capable of producing non-covalent interactions via π–π stacking with CB particles. The hybrid fillers are obtained by precipitating lignin from solutions onto carbon black particles. The fractal nature similar to CB particles and the presence of lignin coating layers on CB particles are confirmed by electron microscopy images. The coating layers are promoted by strong π–π interactions as revealed from Raman spectroscopy and ¹H spin-lattice relaxation data and supported by a drop in zeta potential values. The hybrid fillers show much less networking than CB and reduce the viscoelastic dissipation in model rubber compounds by as much as 10% in comparison to the compounds of only CB.     

Effects of radiation pretreatments on the rubber adsorption power and reinforcing properties of fillers in rubber compounds

Radiation damage to fillers such as carbon black, graphite and silica induced by high doses of γ‐radiation or neutrons dramatically increases their ability to adsorb rubber irreversibly. In fact, the ‘bound rubber’, ie the amount of non‐extractable rubber which remains irreversibly linked to the filler matrix, increases dramatically in radiation‐treated fillers. The increased adsorption power of radiation‐damaged fillers has been attributed to the formation of a higher concentration of surface defects in the form of trapped free radicals, fullerene‐like structures and other kinds of defects. The mechanical properties of rubber compounds filled with radiation‐treated carbon blacks show a significant increase in their reinforcing effects, in line with the increased ability to form ‘bound rubber’. © 2001 Society of Chemical Industry     

Waste pine cones as a source of reinforcing fillers for thermoplastic composites

In this study, we evaluated some physical and mechanical properties of polypropylene (PP) composites reinforced with pine‐cone flour and wood flour. Five types of wood–plastic composites (WPCs) were prepared from mixtures of cone flour, wood flour, PP, and a coupling agent. The water resistance and flexural properties of the composites were negatively affected by an increase in cone‐flour content. Extractives in the cone flour had a significant effect on the flexural properties of the WPCs. However, the flexural properties and water resistance of the WPC samples were not significantly affected by the addition of 10 wt % of the cone flour when compared to the WPC samples made from wood flour. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Biopolymers as effective fillers in natural rubber: Composites versus biocomposites

Biocomposites of natural rubber (NR) blends were prepared with a variety of fillers obtained from renewable resources by a mastication technique. They were characterized for their mechanical properties and morphologies and compared with composites of the conventional filler carbon black (c‐black). The biopolymers exhibited an interesting trend and imparted strength to NR that was quite comparable to c‐black. Up to 30 phr of the fillers could be successfully incorporated; this led to enhancements in the mechanical strength. The properties were found to vary with the type and ratio of filler, namely, starch, cellulose, and chitin. The optimum mechanical strength of the biocomposites was observed at 10 phr. The results were interpreted on the basis of the morphology by scanning electron microscopy, which revealed strong filler–polymer interactions. The moisture‐uptake characteristics of the composites were studied. It was found that addition of biofillers did not lead to a significant increase in the moisture absorption. Furthermore, as the adhesion between the polymer matrix and fillers increased, the water uptake decreased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Waste tyre rubber as a secondary fuel for power plants

Approximately 1 billion waste tyres are generated worldwide each year, with the US producing 300 million and the EU 260 million tyres, representing an enormous waste management problem. At the same time, increasingly stringent emission control targets are being imposed on electric power generating plants. The development of science and technology for clean coal combustion is crucial for a sustainable environment which is dependent on a mix of energy production systems. In this pilot scale study we have shown that tyre rubber can be fired with pulverised coal and may have a role to play in co-firing configurations in full scale power plant boilers as wastes are beginning to feature in ‘fuel switching’ scenarios for CO₂ mitigation. Utilisation of waste tyres in a coal combustion plant can, in one step, reduce NO emissions and recover energy from waste tyres, efficiently. Therefore, through this process, a problem waste stream is effectively utilised to help solve a major environmental pollution problem. We present data demonstrating reburning and co-firing configurations utilising waste tyre rubber. Low levels of NO emission (up to 80% reduction at reburning fuel fractions <12%th) can be achieved, when using a lower volatile South African coal as the primary fuel. The results for tyre reburning are compared with the performance of a suite of reburning fuels with differing volatile hydrocarbon contents. Direct co-firing of tyre with coal can also reduce NO levels but the degree of reduction is dependent on the reactivity of the coal and the prevailing combustion conditions in the primary zone of the mixed fuel flame.     

Polybutadiene-g-polypentafluorostyrene as a coupling agent for lignin-filled rubber compounds

This study investigated the role of polybutadiene-g-polypentafluorostyrene (PB-g-PPFS) as a coupling agent between lignin and styrene butadiene rubber (SBR) in preparation of compounds with higher mechanical strength and lower viscoelastic loss. Lignins are three-dimensional amorphous polymers consisting of benzene rings carrying alkyl, alkoxy, and hydroxyl groups as substituents. These substituents render lignin electron-rich. The PPFS domains in PB-g-PPFS provide an electron-deficient π-ring system that can couple lignin with rubber via arene–perfluoroarene interactions. PB-g-PPFS molecules were synthesized with 2:1 molar ratio of pentafluorostyrene and polybutadiene, respectively. The arene–perfluoroarene interactions were confirmed by UV–vis spectroscopy and the morphology was examined by scanning electron microscopy. The tensile strength improved by 20% and 10% for compounds of lignin and lignin–carbon black hybrid fillers, respectively. The loss tangent value reduced due to improved filler–rubber interactions promoted by PB-g-PPFS compounds.     

橡胶填充增强剂的研究概况

综述了各类橡胶填充增强剂用材料,重点介绍了纳米型材料橡胶填充增强剂的特性。指出了今后橡胶填充增强剂的发展方向。     

Application of rice husk ash as fillers in the natural rubber industry

Rice husk ash (RHA) obtained from agricultural waste, by using rice husk as a power source, is mainly composed of silica and carbon black. A two‐stage conventional mixing procedure was used to incorporate rice husk ash into natural rubber. For comparison purposes, two commercial reinforcing fillers, silica and carbon black, were also used. The effect of these fillers on cure characteristics and mechanical properties of natural rubber materials at various loadings, ranging from 0 to 40 phr, was investigated. The results indicated that RHA filler resulted in lower Mooney viscosity and shorter cure time of the natural rubber materials. The incorporation of RHA into natural rubber improved hardness but decreased tensile strength and tear strength. Other properties, such as Young's modulus and abrasion loss, show no significant change. However, RHA is characterized by a better resilience property than that of silica and carbon black. Scanning electron micrographs revealed that the dispersion of RHA filler in the rubber matrix is discontinuous, which in turn generates a weak structure compared with that of carbon black and silica. Overall results indicate that RHA can be used as a cheaper filler for natural rubber materials where improved mechanical properties are not critical. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 34–41, 2005     

Short fibers as reinforcement of rubber compounds

The effect of aramid, glass and cellulose short fibers on the processing behavior, crosslinking density and mechanical properties of natural rubber (NR), ethylene‐propylene‐diene terpolymer rubber (EPDM) and styrene‐butadiene rubber (SBR) has been investigated. Two fiber percentages (10 and 20 phr) were added to the rubber. The results have shown that the above‐mentioned fibers, especially aramid fibers, are effective reinforcing agents for these rubbers, giving rise to a significant increase in mechanical properties, such as tensile modulus and strength, and tear and abrasion resistance. Moreover, a significant decrease in the time to reach 97% of curing, t′_c (97) is observed, which indicates that the fibers tend to increase the vulcanization rate, regardless of the rubber used. Fibers give also rise to an increase in crosslinking, especially the aramid fibers.     

Natural rubber protein as interfacial enhancement for bio‐based nano‐fillers

Natural rubber was enhanced with soy protein nano‐aggregates and carbon black using a hybrid process. The rubber composites reinforced with an optimum amount of soy protein or soy protein/carbon black showed useful tensile properties. The stress‐strain behaviors were analyzed with a micro‐mechanical model that describes the stress–strain measurements well. The model analysis provides insight into filler network characteristics and entanglement modulus. The composites were also analyzed with both linear and nonlinear viscoelastic properties. Temperature and frequency dependent modulus as well as the model analysis of stress softening effect describe the ability of soy protein to constraint polymer chains in the highly filled composites. For the composites reinforced with soy protein, the good tensile properties are attributed to good filler‐polymer adhesion through the compatibilization effect of natural rubber protein. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2188–2197, 2013     

橡胶填料技术的进步(一)

比较详细地阐述了目前橡胶工业中在用的橡胶填料(包括炭黑,白炭黑及其他)的技术发展动向,分别从结构,性能和品种进行了殷实的介绍。     

白炭黑填充剂对硅橡胶性能的影响

研究了白炭黑对硅橡胶CKTB—Б性能的影响。在胶料中，气相白炭黑的最佳用量为30～40质量份。在使用气相白炭黑的同时加入定量的钛白粉，可提高硫化胶的强度和弹性。     

Waste natural gum as a multifunctional additive in rubber

Bahera gum, extracted from the bark of Terminalia bellerica, is a waste material. The present study involves the use of this natural gum as a multifunctional additive in natural rubber (NR) and brominated isobutylene‐co‐paramethyl styrene (BIMS). Fourier transform infrared (FTIR) analysis was employed to study the functional groups present in the gum. It was found that fatty acids/esters in the gum act as accelerator activator and can replace stearic acid in rubber formulations. Polyphenols in the gum act as antioxidant and the action is comparable with the commercial antioxidant 2,2,4‐trimethyl‐1,2‐dihydroquinoline (TQ) in natural rubber. The gum improves the tack strength of the rubbers (21% at 2.5 phr loading for NR and 54% at 10 phr loading for BIMS). The gum imparts plasticization effect which is reflected in the reduction in k and enhancement in n values, the exponents in the power law equation, with increasing gum concentration. The activation energy of flow is also reduced with the addition of the gum. Moreover, it decreases the elastic memory of the system which causes reduction in die swell. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4897–4907, 2006     

Preparation of novel fillers,named networked silicas,and their effects of reinforcement on rubber compounds

BACKGROUND: A new concept for reinforcing silica, named networked silica, was used to achieve enhanced reinforcing performance of silica and to eliminate the disadvantage of ethanol production and precure through coupling reagents in the preparation of silica‐reinforced SBR compounds. RESULTS: The networked silicas were prepared by connecting silica particles with amine and glycidoxy groups, which had been previously coupled on their surface. The networked silicas compounded in SBR showed a significant enhancement of tensile strength accompanied with a moderate increase in modulus at a high loading of 70 phr even without using any coupling reagents. Their high performance is discussed in relation to their physical and chemical properties investigated using thermogravimetry, infrared spectroscopy, ζ‐potential, transmission electron microscopy and nitrogen adsorption methods. CONCLUSION: The improved reinforcing performance of networked silicas confirmed their feasibility as reinforcing materials for the manufacture of highly stable tires. The high tensile strength achieved using the networked silicas is probably due to the physical entanglements of rubber molecules with the networks formed among silica particles. Copyright © 2008 Society of Chemical Industry     

Influence of nanoclay‐carbon black hybrid fillers on cure and properties of natural rubber compounds

The influence of organically modified nanoclay‐carbon black (CB) hybrid filler on the curing behavior of natural rubber (NR) was explored in this investigation. Here an effort was paid to understand the curing kinetics of organomodified nanoclay filled rubber compounds. On the basis of two different types of modified clay, NR nanocomposites were prepared and cured by a conventional vulcanization system. A faster curing rate and lower torque values were found when the modification was done by quaternary ammonium compounds. The activation energy of the rubber curing process decreased with the incorporation of nanoclay. In addition, it was revealed that the quaternary ammonium compounds used as modifier in the clay show a plasticization effect. Additionally, X‐ray diffraction studies indicated, that the basal spacing of the clay minerals was increased in both cases after incorporation in the rubber matrix. The dynamic mechanical analysis using a strain sweep mode showed that the Payne effect decreases because of an improved dispersion of CB induced by the presence of nanoclay. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

电磁屏蔽橡胶用填料的研究现状

介绍了材料的电磁屏蔽理论,综述了电磁屏蔽橡胶填料的研究现状,填料的种类、形态和用量等因素对橡胶的屏蔽效能有显著的影响.指出复合填料综合了不同材料的优点,具有良好的宽频屏蔽效能,成为电磁屏蔽橡胶填料的主要发展方向.     

Chitosan blends as fillers for paper

The presented studies are focused on the dependence of paper sheet strength properties such as tear resistance, burst, and extensibility on the composition of additive [chitosan blends with poly(vinyl alcohol) and gelated starch]. Chitosan acetate (cationic) and its blends caused an improvement of the strength properties of paper sheets by the substantial modification of cellulose (anionic) fibers, probably through the presence of strong ionic interactions. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3210–3215, 2000