Rubber Filler Research Articles

Impact of Placement of Aminopropyl Triethoxy Silane and Tetraethoxy Silicate on SSBR Chains: Analysis of Rolling Resistance, Wet Grip, and Abrasion Resistance

Solution styrene-butadiene rubber (SBR) and silica filler have attracted a significant attention because of their superior properties in cured rubber mixtures used in automobile tire industry. One of the challenges ahead of using these materials is the hard dispersion of silica with its polar surface in SBR nonpolar rubber. In the present study, the synthesis of styrene-butadiene rubber by solution polymerization method with polymer chain modification using copolymer functionalization was performed. For this purpose, two materials, namely, aminopropyl triethoxy silane (APTES) and tetraethoxy silicate (TEOS), were employed to improve the silica dispersion in the mixture. The results of postsynthesis structural tests show the successful placement of functional groups on the polymer chain. The results of mechanical, dynamic, and imaging analyses of the cured mixtures showed an improvement in the APTES-containing samples rolling resistance, wet surface grip, and abrasion resistance by 39%, 18%, and 17%, respectively, due to having stronger physical and chemical bonds with silica and also the usage of end agents in the polymer chain. The samples containing TEOS had also better results than the conventional SBR rubber. In addition, a sample containing emulsion styrene-butadiene rubber was prepared to compare its properties with those of the solution SBR. Another SBR sample containing silane coupling agent was also prepared to investigate its performance compared to that of the agents placed on the polymer chain. The abrasion resistance, rolling resistance, and wet grip of the coupling agent containing sample showed 2%, 10%, and 30% improvement, respectively, which were very close to those of the sample containing the TEOS agent. In this work, various techniques including, rheometry, wear, rolling, hardness, bound rubber content, dynamic mechanical thermal analysis (DMTA), and field emission scanning electron microscopy (FE-SEM) were employed to analyze the synthesized rubber.

Features of cast iron for railway brake pads

Thepaperpresentstheresultsof comparison of quality indices of brake shoes for railroad rolling stock made of synthetic cast iron smelted in induction furnaces and of composite material which is a vulcanized mixture of rubber and different fillers. Disclosed are the disadvantages of composite brake pads. Defects of the working surface of the railway rolling stock wheels rolling surface caused by the application of composite brake pads made of rubber-asbestos or rubber-asbestos mixture are shown. Parameters of C, Si, Mn, P, S content and carbon equivalent distribution in cast iron used for the production of «M» type brake shoes according to GOST 30249-97 are analysed. It is established that the hardness and fracture strength of pads do not correlate with the content of chemical elements in cast iron and its carbon equivalent. The ranges of C, Si, Mn, P, S distributions in the specified purpose cast iron are much narrower than the allowable limits of these elements specified in GOST 30249–97. Suggestions for improving the standards are given.

Compliant materials based on nickel oxide/chlorinated natural rubber nanocomposites

AbstractThis research article focuses on the preparation of chlorinated natural rubber (Cl‐NR)/nickel oxide (NiO) nanocomposites by a simple and greener two‐roll mill mixing technique. X‐ray diffraction study of the rubber nanocomposites showed the systematic arrangement of NiO nanoparticles in the polymer indicates the improved crystallinity of the nanocomposites. The composite prepared with a nanofiller content of 5 phr (parts per hundred parts of rubber) exhibited the best homogenous dispersion of filler in rubber as evident from field emission scanning electron microscopy and HRTEM images. The glass transition temperature obtained from differential scanning calorimetry (DSC) was found to be increased with an increase in the concentration of nanofiller in the polymer. The flame resistance of rubber composites was significantly improved with increasing the filler content and this aids the fabrication of fire‐resistant household gadgets. The AC conductivity and dielectric behavior of composites were scrutinized with special emphasis on filler loading at various frequencies. The AC conductivity, dielectric loss and dielectric constant of the nanocomposites were higher than pure Cl‐NR. The cure time was considerably reduced with the incorporation of filler, resulting in the easy fabrication of rubber products at a cheaper rate. The mechanical properties (tensile strength, modulus, hardness, tear resistance, heat build‐up) of the nanocomposites were increased with the addition of NiO indicating its high reinforcing ability. The maximum mechanical and electrical properties were observed for 5phr NiO loaded nanocomposite and these samples can be potential candidates for the fabrication of electromagnetic induction shielding materials, conducting adhesives and flame resistant flexible electronic devices.

Ultrafine Grinded and Silane Grafted Iron Ore Tailings as Reinforcing Filler of Styrene Butadiene Rubber.

In order to realize the high value-added resource utilization of solid waste and reduce the cost of rubber manufacturing, iron ore tailings (IOTs) were used as raw material to prepare a reinforcing filler of rubber through ultrafine grinding and surface organic modification techniques. We studied the effects of ball mill grinding conditions on the particle size and distribution of grinded iron ore tailings (G-IOTs). The effects of bis-(triethoxy-silyl-propyl)-tetrasulfide (Si69)-modified G-IOT (Si69-G-IOT) loading levels on the cure characteristics, static mechanical and dynamic mechanical properties of the styrene butadiene rubber (SBR) composites were also explored in this paper. The grinding and modification mechanism of IOTs and the combination of filler and SBR matrix were explored by grinding simulation of population balance model, X-ray diffraction analysis, Fourier transform infrared spectroscopy and scanning electron microscopy. The results showed that when grinding IOTs at 2000 r/min for 150 min, the particle size distribution of the resulting G-IOTs was the narrowest, with a D90 value of 4.42 μm. The tensile strength and elongation at break of SBR filled with 120 phr Si69-G-IOT were 14.97 MPa and 596.36%, respectively.

Hybrid nanocellulose/carbon nanotube/natural rubber nanocomposites with a continuous three‐dimensional conductive network

AbstractIn this study, the hybrid effect of nanocellulose/carbon nanotube (NCC/CNT) reinforcement on natural rubber (NR) nanocomposites was investigated. To this end, three series of NR nanocomposites were prepared: NCC/NR, CNT/NR and NCC/CNT/NR. First, the nanocomposites morphology and the filler–rubber interactions were studied using scanning electron microscopy (SEM) and the swelling behavior in toluene, respectively. The results showed that the presence of NCC improved the NCC/CNT hybrid filler dispersion forming a 3D network, while the presence of CNT increased the filler–matrix interaction. The curing results also confirmed that the degree of crosslinking increased when hybrid fillers were used, but the curing time was not modified. In addition, it was observed that using a NCC/CNT hybrid system led to superior mechanical properties, dynamic mechanical properties and thermal conductivity than each material used separately. When 10 phr hybrid filler (with a filler ratio of 1) was added to NR, the tensile strength, modulus at 300% elongation (M300), storage modulus at 10% strain and thermal conductivity were all increased by 57%, 137%, 120%, and 30%, respectively. The results also showed that the NR nanocomposites properties can be controlled by tuning the NCC/CNT filler ratio.

Reuse of Electric Arc Furnace Slag as Filler for Nitrile Butadiene Rubber

This work shows an innovative application for electric arc furnace (EAF) slag: its use as a filler for nitrile butadiene rubber (NBR). Composites with various EAF slag contents were tested. It was found that the polymer matrix significantly reduces the leaching of slag (determined according to the standard CEN-EN 12457-2) incorporated in the NBR. The processability characteristics determined by the rheometric curves highlight that the EAF slag accelerates the crosslinking kinetics, reducing the production cycle time. Mechanical characterization demonstrated that EAF slag increases hardness and compression modulus. The ability to recover an imposed deformation quantified by the compression set is reduced as the EAF slag amount increases but remains below an acceptable value. It can be stated that in sealing systems, the EAF slag as a filler for NBR positively affects the compound properties. Moreover, NBR filled with EAF slag also has magnetic properties compared with standard rubber.

Variation of air permeability in bromobutyl rubber/epoxidized natural rubber composites: Influence of structure of filler particle

AbstractThe effect of carbon black structure on dispersion and barrier properties in BIIR/ENR 50 blends is studied extensively in this paper. Carbon blacks with different dibutyl phthalate values are used for the study and it is found that the structure of carbon black strongly affects both the mode of dispersion as well as barrier properties of the end product. The morphology of various carbon blacks in their raw state and in the matrix was studied using scanning electron microscopy and transmission electron microscopy techniques. The influence of carbon black structure on the reinforcing was studied by analyzing the physical properties. The rubber–filler interaction was measured using bound rubber content and filler–filler interaction was studied using rubber processing analyzer. For the same loading of carbon black, the high structure carbon black is more difficult to disperse in BIIR/ENR 50 blends compared to the low structure carbon black, leading to changes in permeability properties.

The rheological and mechanical properties of natural rubber/graphene composites

This research focuses on the use of graphene as a filler for natural rubber (NR). The purpose of using graphene is to improve the mechanical properties of rubber compounds and their processing characteristics. Graphene (G) consists of carbon atoms and is an essential filler for polymers to enhance electrical and mechanical properties. The addition of graphene to rubber can improve the wear resistance and mechanical strength of rubber products. Thus, the effect of the graphene filler composition is interesting to study. Variety of graphene loads (10, 20, and 30 part hundred rubber (phr)) were combined with a variety of sulfur fillers (S) (10 and 20 phr) and then composited with natural rubber. The effect of variations in a load of graphene and sulfur fillers on the rheological properties, abrasion resistance, and compression set were studied. The results showed that the optimal combination of the G/S load variation was 20/10 phr. It leads to a more extraordinary strengthening ability that is binding rubber molecules so that the interactions occurred, both physical and chemical, could be formed better with the NR molecular chain. This resulted in distinct rheological properties enhancement such as torque modulus and curing time. In contrast, the mechanical properties like abrasion resistance and compression set were still good. The FTIR Spectra of natural rubber-graphene composites confirmed that good filler disperses were obtained due to several intramolecular interactions of carbon graphene with NR molecules. Graphene can be used as a filler for rubber products, mainly rubber, abrasion, and compression resistant, and an alternative for commercial fillers.

Mechanical and thermal properties of NR/XSBR composite reinforced with rice husk silica

Natural rubber (NR) is a renewable resource that is used in many products. In the production of NR products, other rubbers or fillers may be used to produce a product with required properties. However, most rubbers and fillers are synthetic which are non-environmentally friendly materials. To solve this problem, rice husk ash (RHA) from biomass power plant was used to prepare silica to be used as a filler in rubber by in-situ generation. The purer RHA was prepared by leaching with HCl to remove some metallics and increase silica contents by combustion. The purer RHA was dissolved in NaOH to obtain sodium silicate from RHA (RSS). Carboxylated styrene-butadiene rubber (XSBR) used as synthetic rubber was blended with NR in latex form. NR/XSBR at the ratio of 2:1 was mixed with RSS to obtain NR/XSBR/RSS mixture. Acetic acid was dropped into the mixture until neutral for precipitating silica to obtain NR/XSBR/RSi composite. The mechanical, morphological, and thermal properties of NR/XSBR/RSi composites at different contents of silica (5, 10, and 15 phr) were studied. The NR/XSBR/RSi composite with optimum content was compared with NR/XSBR/CSi composite which prepared silica from commercial sodium silicate (CSS) on mechanical, morphological, and thermal properties.

Upcycling green carbon black as a reinforcing agent for styrene-butadiene rubber materials.

This study reports the effects of recovered carbon black (produced in a clean and sustainable way) as a reinforcing agent on the physicochemical properties of a styrene-butadiene rubber (SBR) matrix. SBR-based composite materials are prepared with recovered green carbon black (GCB), and these are thoroughly compared to the composite materials containing conventional virgin carbon black (VCB) (produced by the incomplete combustion of petroleum products). The GCB-SBR composite materials generally show detectably inferior properties compared to the VCB-SBR composite under the same preparation conditions due to the limited functionality of the GCB filler. However, the introduction of a small amount of crosslinker, acrylate-functionalized POSS (polyhedral oligomeric silsesquioxane), into the GCB-SBR composite materials effectively enhances the overall physical properties, including the tensile strength, fracture elongation, and thermal stability. The degree of the crosslinking efficiency, thermal stability, and mechanical properties of the composite materials are optimized and thoroughly examined to demonstrate the possibility of replacing typical VCB with GCB, which can allow for upcycling the inexpensive and ecofriendly carbon black materials as effective reinforcing fillers.

Investigation on Electrical, Thermal, and Mechanical Properties of Silicone Rubber ATH Nanocomposites

In the present study, investigations have been carried out by choosing the nano-sized ATH (30 – 50 nm) particles as filler content in silicone rubber to acquire a deep insight to understand the use of nano ATH fillers in silicone rubber on its performance, to use it as insulation structure as an outdoor insulator. Variation in the surface condition of silicone rubber nanocomposites due to corona aging and the recovery characteristics analysis carried out through contact angle measurement. Nano ATH added in silicone rubber, up to 3 wt% of filler, shows increased dielectric constant with less loss factor. Water droplet-initiated discharges on silicone rubber nano ATH composites under DC voltage measured using UHF technique and the damage caused zone analyzed through AFM studies and by surface potential measurement, which indicates higher surface roughness and increased charge trap depth. It is observed that negative DC voltage has higher CIV followed by positive DC and AC voltage. Laser Induced breakdown studies (LIBS) show a direct correlation between plasma temperature and material surface hardness. Also, on laser shining on the surface of the specimen, its temperature was measured on the backside of the specimen through thermal imaging confirming increased diffusivity of temperature. Laser flash analysis shows a direct correlation between filler content in base polymer and thermal conductivity and diffusivity. Higher storage modulus and activation energies measured from the dynamic mechanical analysis indicate the significance of prepared composites as an excellent mechanical support structure for the power system network.

Effect of Organomodified Bentonite/Silica Hybrid Filler Compound System on Mechanical Properties and Sealing Performance of NR/NBR Rubber Seal for LPG Tube Valve

Organomodified bentonite and silica were used as hybrid fillers in natural rubber (NR)/nitrile butadiene rubber (NBR) seal for liquified petroleum gas (LPG) tube valve compound to evaluate their interaction and influence on mechanical properties and sealing performance. In this work, the NR-organomodified bentonite were prepared by the in situ organomodified and latex compounding method with varying amounts of bentonite then applied in the silica-NR/NBR rubber seal compounds with mixing process held in two rolls open mill. Silanization reaction, Payne effect, curing characteristics, tensile properties, compression set, hardness, uniaxial compression and sealing performance were assessed. The study obtained that NR/NBR-silica/organomodified bentonite show improved silica dispersion physically, as analyzed by Payne effect. The presence of organomodified bentonite decreases the vulcanization reaction. The cure rate index, apparent crosslink density and hardness tend to decrease with addition of organomodified bentonite, while tensile strength and elongation at break are enhanced with increasing organomodified bentonite. With an appropriate amount of organomodified bentonite (organomodified bentonite below 4 phr), the introduction of organomodified bentonite enhances the elastic response of the material, as shown by increasing of tensile properties. The rubber seal’s sealing performance analysis revealed that B4 (4 phr organomodified bentonite) performed the best, with contact stress higher than the actual working pressure and Misses stress lower than the actual working pressure, making it difficult to crack.

Preparation of carbon black/silicone rubber composites with large-area-homogeneous-low electrical-resistance used as electroplating matrix.

Conductive carbon black (CCB) is an important filler in stretchable conductive silicone rubber (CSR) composites. However, due to the active oxygen-containing groups on CCB, introducing it into silicone rubber (SR) may cause SR to not completely cure. Surface modification of CCB may ease the problem but at the cost of reducing the electrical conductivity of pristine CCB. In this work, the curing and crosslinking performance of CCB/SR is detected in detail, the hydroxyl groups (-OH) carried by CCB can react with the silicon-hydrogen group (Si-H) with the existence of Pt catalyst, causing insufficiency of the hydrosilylation reaction thus hindering the solidifying process of silicon rubber. To take advantage of this reaction, more hydrogen silicone oil (PHMS) possessing silicon-hydrogen bonds is introduced into the system to improve the curing degree as well as fix the CCB in the crosslinked network. Due to the lock-in effect of CCB, the resistance of CSR samples is stable after several hundred bending cycles, and the composite's tensile strength is three times that of the pure SR samples. Besides, the size of the composites can expand to dozens of centimeters or even a few meters with uniform electric conductivity. This composite has resistance as low as 10.20 Ω and is suitable to make electroplating mold, and a rapid plating rate of 2.4 mm/24 h can be achieved. Meanwhile, the overall properties make this CSR composite have potential applications in mold manufacture, flexible electronics, and other related fields.

The effect of silica filler quartz sand from tailing processing of mining material on mechanical properties, thermal aging and morphology rubber compound

Tailings as waste from mining material processing contain constituents that have the potential to be exploited economically. Tailings deposits derived from tin mines include quartz sand with a SiO2 content of 98.03%, which can function as a filler for rubber products. This research studied silica quartz sand as a mineral filler in natural rubber (NR) on rubber’s mechanical and thermal aging characteristics. The effect of reinforced filled in NR was observed by varying 0, 10, 20, 30, 40, and 50 phr of the filler. The thermal aging test is carried out at 70 °C and 100 °C for a storage period of 72 hours. SEM micrographs were used to examine morphology. The results showed that using silica quartz sand as a filler improved various properties, including tensile strength, tear strength, elongation at break, hardness, and abrasion resistance. The higher the grinding temperature, the higher the hardness and tensile strength, but the lower the elongation at break. Morphological analysis using SEM micrographs revealed the system’s strengths and weaknesses. The silica particles are homogeneously mixed with natural rubber, according to SEM analysis. According to the findings of this study, the silica of quartz sand from tin mining processing industrial waste can be used as a cost-effective alternative filler in NR compounding.

Synthesis of a grape-like conductive carbon black/Ag hybrid as the conductive filler for soft silicone rubber.

Conductive silicone rubber (CSR) is an outstanding stretchable conductive composite due to its excellent mechanical properties and stable conductivity. In this paper, silver nanoparticles were deposited on carbon black (CB) through a reduction reaction. The uniform dispersion of silver particles on the surface of CB as well as the grape-like branch structure of hybrid particles was formed by the condensation reaction of the hydroxyl groups of CB with (3-mercaptopropyl) trimethoxysilane (KH-590), along with the interattraction between sulfhydryl groups of KH-590 and silver ions. This sulfhydryl modified conductive carbon black/Ag hybrid filler (SMCB@Ag) avoided the high processing viscosity of CSR caused by the hydroxyl groups of CB. The percolation threshold of CSR made from SMCB@Ag was 5.5 wt% according to the percolation equation. With the addition amount of SMCB@Ag increasing to 10 wt%, the conductivity of CSR increased from 10−5 to about 101. Moreover, the conductivity of this CSR showed excellent stability with extension of storage time and increase of stretching-recovery cycles.

Anisotropic properties of styrene-butadiene rubber filled with single-wall nanotubes

A study of the mechanical behavior of elastomeric nanocomposites with a styrene-butadiene rubber matrix and filler in the form of single-wall nanotubes TUBALL ™ (made by OCSiAl) has been carried out. Materials filled by N-330 grade Carbon Black as a nanofiller was used for comparison. Studies have shown that the introduction of a small amount of nanotubes (7 phr) into styrene-butadiene rubber significantly affects the viscoelastic properties of the material, the softening effect and the growth of residual strain. In addition, the material becomes substantially anisotropic during the milling process. The rigidity of the material in one direction is many times higher than the rigidity in the perpendicular direction

Fabrication of Natural Rubber Latex Foam Composite Filled with Pineapple-leaf Cellulose Fibres

Pineapple leaf (PL) is a renewable agriculture residue which are abundance in Thailand. In this paper, cellulose powder was extracted from PL. Celluloses are typically used as fillers for rubber reinforced composites due to their properties such as high mechanical properties, low cost, low density, and biodegradability. The aim of this study was to optimize the method to prepare natural rubber latex foam (NRLF) with different cellulose loadings from 0 to 7 phr by using Dunlop method. The different steps for adding celluloses in this study were adding in pre-vulcanization process and in foaming process were studied. The tensile properties, density, compression, and microstructural characterization were studied. Morphological and microstructural performed by using scanning electron microscopy (SEM). It was found that adding cellulose in pre-vulcanization step showed well distribution of cellulose while adding cellulose in foaming process showed the settle of cellulose at the bottom of the foam sample. The tensile strength and elongation at break decreased with increasing of cellulose content whereas modulus increased with increasing of cellulose content.

CARBOXYLATION OF CELLULOSE-CONTAINING RAW MATERIALS AND ITS USE IN THE COMPOSITION OF LIMITED SWELLING RUBBERS

The purpose of the study is to develop a method for intensifying the process of obtaining a partially carboxylated product based on powdered cellulose from flax straw and to study its effect on the complex of physicomechanical and sorption properties of limited swelling rubbers based on NBR rubber. The paper considers the production of a partially carboxylated product based on powdered cellulose from flax straw. Carboxylated cellulose is used as a heavy metal sorbent, in the oil industry to control the properties of drilling fluids in well drilling, and as a swelling rubber filler for limited swelling rubbers. To intensify the carboxylation process, microwave radiation (MWR) of various powers was used. The carboxylation process was carried out in two stages. At the first stage, cellulose-containing raw materials from flax straw were treated with potassium hydroxide. Next, the calculated amount of monochloroacetic acid was added to the reaction mass. Products with the content of carboxyl groups from 23 to 42 meq have been obtained. It was found that the introduction of carboxylated powdered cellulose from flax straw, as well as powdered cellulose, into the rubber composition makes it possible to maintain the conditional tensile strength of rubbers at the level of the sample without a swelling filler, while the introduction of an industrial product of carboxylated cellulose Na-CMC leads to a significant decrease in the strength of rubber.

Studies on reinforcing effect of industrial nano silica in chloroprene vulcanizates containing carboxy-terminated liquid natural rubber

Maleic anhydride was chemically attached to depolymerized natural rubber, and the product was named as carboxy-terminated liquid natural rubber (CTNR). The CTNR can act as a potential plasticizer in chloroprene (CR) vulcanizates. This paper describes the use of commercial nano silica (NS) as a promising cost-effective filler, which can enhance the tensile properties and ageing resistance of the CR vulcanizates incorporated with CTNR (CR-CTNR). The enhancement in properties may be attributed to the increased bound-rubber content owing to the large surface area of the nano-sized filler. The characteristics of the NS-filled CR vulcanizates containing CTNR (NS CR-CTNR) were compared with those containing amorphous silica. The NS CR-CTNR vulcanizates showed superior ageing and oil resistance due to the finer rubber filler interaction modified by ionic cross linking.

Green polymer nanocomposites based on natural rubber and nanocellulose whiskers from Acacia caesia: Mechanical, thermal, and diffusion properties

Elastomer composites with biomaterial for high performance have been the recent focus on rubber technology. In the present work, nanocellulose whiskers (NCW) are dispersion in water mixed with natural rubber (NR) latex to fabricate NR-NCW composites. The renewable source of NCW is Acacia Caesia, a medicinal plant with high cellulose content. The morphological analysis shows a homogeneous distribution of NCW in the NR matrix with an average size of 30 nm when the NCW content is 2phr. The addition of 2phr NCW in NR dramatically enhanced tensile strength by 21.5% and modulus by 223% relative to NR gum. The maximum degradation temperature of NR-gum and NR-NCW-2phr is 368 °C and 372 °C, respectively, confirming the composite's thermal stability. The higher crosslink density of NR-NCW-2phr confirmed the superior rubber filler interactions in the NR matrix.