Unsaturated polyester as compatibilizer for styrene–butadiene (SBR)/acrylonitrile–butadiene (NBR) rubber blends

The effect of the addition of 5 and 10 phr of unsaturated polyester resin (UPE) on the compatibility and physicomechanical properties of styrene–butadiene (SBR) and acrylonitrile–butadiene (NBR) rubber blends was studied. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM), electrical, and ultrasonic techniques were used to determine the degree of the compatibility (DC). The results obtained revealed that, by the addition of 10 parts per hundred parts of rubber (phr) UPE as a compatibilizer for SBR/NBR blends, the degree of compatibility was greatly enhanced. The rheological and mechanical properties of the blends were also improved. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2314–2321, 2002     

Studies on coconut shell powder and crysnanoclay incorporated acrylonitrile‐butadiene rubber/ styrene butadiene rubber (NBR/SBR) green nanocomposites

The development of commercially viable “green products” based on natural resources for both matrices and reinforcements for a wide range of applications is on the rise. This effort includes new pathways to produce natural polymers with better mechanical properties and thermal stability using nanotechnology and use of naturally occurring fillers such as lignocellulosic and hemicellulose to make biodegradable rubber composites. The blends of acrylonitrile butadiene rubber (NBR) and styrene butadiene rubber (SBR) with coconut shell powder (CSP) have been prepared by using a compounding technique in presence of different amounts of crysnanoclay (CN). The effect of CN loading on tensile properties, thermal properties, swelling behavior, and water uptake behavior were studied. Significant improvement of Young's modulus and tensile strength was observed as a result of addition of nanoclay to the rubber matrix especially at 10 wt% loading. Presence of CSP resulted in ahigher in water sorption but after incorporation of CN the water sorption tended to decrease. Thermal characteristics were performed using thermogravimetric analysis (TGA). TGA thermograms indicated that incorporation of CSP filler decreases the thermal stability of nanocomposites. The dispersion of CSP and CN in rubber matrix was analyzed from scanning electron microscopy. POLYM. COMPOS., 38:727–735, 2017. © 2015 Society of Plastics Engineers     

Morphology and mechanical properties of clay/styrene‐butadiene rubber nanocomposites

Based on the character of a clay that could be separated into many 1‐nm thickness monolayers, clay styrene‐butadiene rubber (SBR) nanocomposites were acquired by mixing the SBR latex with a clay/water dispersion and coagulating the mixture. The structure of the dispersion of clay in the SBR was studied through TEM. The mechanical properties of clay/SBR nanocomposites with different filling amounts of clay were studied. The results showed that the main structure of the dispersion of clay in the SBR was a layer bundle whose thickness was 4–10 nm and its aggregation formed by several or many layer bundles. Compared with the other filler, some mechanical properties of clay/SBR nanocomposites exceeded those of carbon black/SBR composites and they were higher than those of clay/SBR composites produced by directly mixing clay with SBR through regular rubber processing means. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1873–1878, 2000     

Properties of silica‐filled styrene‐butadiene rubber compounds containing acrylonitrile‐butadiene rubber: The influence of the acrylonitrile‐butadiene rubber type

Because silica has strong filler‐filler interactions and adsorbs polar materials, a silica‐filled rubber compound exhibits poor dispersion of the filler and poor cure characteristics in comparison with those of a carbon black‐filled rubber compound. Acrylonitrile‐butadiene rubber (NBR) improves filler dispersion in silica‐filled styrene‐butadiene rubber (SBR) compounds. The influence of the NBR type on the properties of silica‐filled SBR compounds containing NBR was studied with NBRs of various acrylonitrile contents. The composition of the bound rubber was different from that of the compounded rubber. The NBR content of the bound rubber was higher than that of the compounded rubber; this became clearer for NBR with a higher acrylonitrile content. The Mooney scorch time and cure rate became faster as the acrylonitrile content in NBR increased. The modulus increased with an increase in the acrylonitrile content of NBR because the crosslink density increased. The experimental results could be explained by interactions of the nitrile group of NBR with silica. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 385–393, 2002     

Preparation and characterization of poly(styrene‐co‐butadiene) and polybutadiene rubber/clay nanocomposites

Poly(styrene‐co‐butadiene) rubber (SBR) and polybutadiene rubber (BR)/clay nanocomposites have been prepared. The effects of the incorporation of inorganically and organically modified clays on the vulcanization reactions of SBR and BR were analysed by rheometry and differential scanning calorimetry. A reduction in scorch time (t_s1) and optimum time (t₉₅) was observed for both the rubbers when organoclay was added and this was attributed to the amine groups of the organic modifier. However, t_s1 and t₉₅ were further increased as the clay content was increased. A reduction in torque value was obtained for the organoclay nanocomposites, indicating a lower number of crosslinks formed. The organoclays favoured the vulcanization process although the vulcanizing effect was reduced with increasing clay content. The tensile strength and elongation of SBR were improved significantly with organoclay. The improvement of the tensile properties of BR with organoclay was less noticeable than inorganic‐modified clay. Nevertheless, these mechanical properties were enhanced with addition of clay. The mechanical properties of the nanocomposites were dependent on filler size and dispersion, and also compatibility between fillers and the rubber matrix. Copyright © 2004 Society of Chemical Industry     

Impact of blend ratio on the properties of graphene oxide‐filled carboxylated acrylonitrile–butadiene rubber/styrene–butadiene rubber blends

Carboxylated acrylonitrile–butadiene rubber (XNBR) and styrene–butadiene rubber (SBR) composites with 3 phr (parts per hundred rubber) graphene oxide (GO) were prepared using a latex mixing method. Effects of XNBR/SBR blend ratios on the mechanical properties, thermal conductivity, solvent resistance and thermal stability of the XNBR/SBR/GO nanocomposites were studied. The tensile strength, tear strength, thermal conductivity and solvent resistance of the XNBR/SBR/GO (75/25/3) nanocomposite were significantly increased by 86, 96, 12 and 21%, respectively, compared to those of the XNBR/SBR (75/25) blend. The thermal stability of the nanocomposite was significantly enhanced; in other words, the temperature for 5% weight loss and the temperature of the maximal rate of degradation process were increased by 26.01 and 14.97 °C, respectively. Theoretical analysis and dynamic mechanical analysis showed that the GO tended to locate in the XNBR phase, which led to better properties of the XNBR/SBR/GO (75/25/3) nanocomposite. © 2017 Society of Chemical Industry     

Preparation and structure and mechanical properties of poly(styrene‐b‐butadiene)/clay nanocomposites

Star‐shaped and linear block thermoplastic poly(styrene‐b‐butadiene) copolymer (SBS)/organophilic montmorillonite clays (OMMT) were prepared by a solution approach. The intercalation spacing in the nanocomposites and the degree of dispersion of nanocomposites were investigated by X‐ray diffraction (XRD) and transmission electron microscopy (TEM), respectively. The mechanical properties, dynamic mechanical properties, and thermal stability of these nanocomposites were determined. Results showed that SBS chains were well intercalated into the clay galleries and an intercalated nanocomposite was obtained. The mechanical strength of nanocomposites with the star‐shaped SBS/OMMT were significantly increased. The addition of OMMT also gave an increase of the elongation, the dynamic storage modulus, the dynamic loss modulus, and the thermal stability of nanocomposites. The increase of the elongation of nanocomposites indicates that SBS has retained good elasticity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3430–3434, 2004     

Study on flammability of montmorillonite/styrene‐butadiene rubber (SBR) nanocomposites

The flammability of montmorillonite (MMT)/SBR nanocomposites, prepared by the technique of cocoagulating rubber latex and clay aqueous suspension, was investigated. Flammability studies, performed on the cone calorimeter, showed that the maximum heat release rate (HRR) of SBR decreased from 1987 to 1442 kw/m² with the introduction of nanoclay (20 phr). This nanocomposite had the lowest mass loss rate and the largest amount of char upon combustion compared with conventional SBR composites with the same clay loading and pure SBR. The permeability properties of MMT/SBR composites were also measured. It was deduced that the lowered permeability was responsible for the reduced mass loss rate and hence the lower HRR. Unfortunately, the oxygen index (OI) of the nanocomposites was not as high as expected. Combination of Mg(OH)₂ and clay was effective for the improvement of both mechanical properties and OI. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 844–849, 2005     

Improvement of properties of silica‐filled styrene–butadiene rubber compounds using acrylonitrile–butadiene rubber

Since silica has strong filler–filler interactions and adsorbs polar materials, a silica‐filled rubber compound has a poor dispersion of the filler and poor cure characteristics. Improvement of the properties of silica‐filled styrene–butadiene rubber (SBR) compounds was studied using acrylonitrile–butadiene rubber (NBR). Viscosities and bound rubber contents of the compounds became lower by adding NBR to the compound. Cure characteristics of the compounds were improved by adding NBR. Physical properties such as modulus, tensile strength, heat buildup, abrasion, and crack resistance were also improved by adding NBR. Both wet traction and rolling resistance of the vulcanizates containing NBR were better than were those of the vulcanizate without NBR. The NBR effects in the silica‐filled SBR compounds were compared with the carbon black‐filled compounds. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1127–1133, 2001     

A comparative study on dispersion of carbon nanotubes in (styrene‐butadiene rubber)‐based nanocomposites

The efficient dispersion of carbon nanotubes (CNTs) is a challenging task in reaching the usable nanocomposites. In this study, a comparative analysis on dispersion of multiwalled CNTs multiwalled carbon nanotubes (MWNTs) in styrene‐butadiene rubber (SBR) latex was carried out by using two anionic surfactants, sodium dodecyl benzene sulfonate and sodium lauryl sulfate. The MWNTs were first predispersed in distilled water using two surfactants individually followed by gentle mixing the MWNT predispersion into SBR latex. By using the technique of ultraviolet‐visible spectroscopy, the study on MWNT dispersion in aqueous media was focused on surfactant concentration, MWNT functionality, and ultrasonication time. The ultraviolet‐visible absorptions showed the positive effect of MWNT functionality in addition to surfactant concentration with no great effect of ultrasonication time over 15 min. In comparison with sodium lauryl sulfate, the existing benzene ring in the sodium dodecyl benzene sulfonate structure seems to result in higher adsorption of surfactant onto the MWNTs surface and, hence, better MWNT dispersion. The MWNT dispersion was further improved by using hydroxyl functionalized MWNTs mainly because of the formation of hydrogen bonding between the hydrophilic head of surfactant and the existing hydroxyl group of the functionalized MWNTs. After mixing the MWNT predispersion into SBR latex, the dispersion of MWNTs was further characterized by using electrical volume conductivity, microscopy technique, and rheological measurements. In rheometry tests of the lattices, the storage modulus at terminal zone was utilized for tracking the degree of MWNT dispersion in the nanocomposite. The pictures of scanning electron microscopy showed the efficiency of MWNT functionality in enhancing the degree of dispersion. In conductivity tests, the percolation threshold was obtained at about 1 part by weight per hundred parts of resin of the functionalized MWNT in dried film. J. VINYL ADDIT. TECHNOL., 23:28–34, 2017. © 2015 Society of Plastics Engineers     

Gas permeation of polymer blends. II. Poly(vinyl chloride)/acrylonitrile–butadiene copolymer (NBR) blends

The transport behavior of He, O₂, N₂, and CO₂ in a series of PVC/NBR polymer blends with varying acrylonitrile (AN) content in the NBR component has been studied at 25° and 50°C. In addition, measurements of density, crystallinity, and thermal expansion coefficients were carried out. The transport behavior of these blends is similar to previous result for PVC/EVA.¹. With increasing AN content in NBR, the permeability (P) and diffusivity (D) of the permeants decreased while the activation energy for diffusion (E_D) increased. For the polymer blends, better additivity of permeability and diffusivity was observed with increasing AN content in the NBR component. The polymer blends also showed increasing volume contraction with increasing AN content in the NBR component. These effects have been discussed as due mainly to increased polymer–polymer interaction causing reduced segmental mobility and increased compatibility of the two polymers. The sorption values calculated from P/D ratios were largely irregular and fluctuated with the blend composition. They were less reproducible than other transport parameters, i.e., P and D measured separately. Several reasons for the irregular sorption behavior were proposed.     

Preparation and properties of MWCNTs/poly(acrylonitrile‐ styrene‐butadiene)/epoxy hybrid composites

Poly(acrylonitrile‐styrene‐butadiene) (ABS) was used to modify diglycidyl ether of bisphenol‐A (DGEBA) type epoxy resin, and the modified epoxy resin was used as the matrix for making multiwaled carbon tubes (MWCNTs) reinforced composites and were cured with diamino diphenyl sulfone (DDS) for better mechanical and thermal properties. The samples were characterized by using infrared spectroscopy, pressure volume temperature analyzer (PVT), thermogravimetric analyzer (TGA), dynamic mechanical analyzer (DMA), thermo mechanical analyzer (TMA), universal testing machine (UTM), and scanning electron microscopy (SEM). Infrared spectroscopy was employed to follow the curing progress in epoxy blend and hybrid composites by determining the decrease of the band intensity due to the epoxide groups. Thermal and dimensional stability was not much affected by the addition of MWCNTs. The hybrid composite induces a significant increase in both impact strength (45%) and fracture toughness (56%) of the epoxy matrix. Field emission scanning electron micrographs (FESEM) of fractured surfaces were examined to understand the toughening mechanism. FESEM micrographs reveal a synergetic effect of both ABS and MWCNTs on the toughness of brittle epoxy matrix. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mechanical properties of gamma‐irradiated styrene‐butadiene rubber/acid‐treated vermiculite clay/maleic anhydride nanocomposites

Nanoparticle vermiculite (VMT) clay was prepared by treatment with hydrochloric acid. Styrene‐butadiene rubber (SBR) nanocomposites were prepared by mixing different contents (2.5, 5, 7.5, and 10 phr) of untreated (VMT) and acid‐treated (DVMT) vermiculite clay, respectively. In addition, different contents (3, 7, and 10 phr) of maleic anhydride (MA) as compatibilizer were mixed via direct melt compounding in internal mixer. The effect of gamma irradiation, VMT clay, and MA contents on the mechanical properties was studied. The acid‐treated VMT clay was characterized by x‐ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FT‐IR) spectroscopy. Meanwhile, the SBR/VMT composites, SBR/DVMT, and SBR/DVMT/MA nanocomposites were characterized via crosslinking density and tensile mechanical testing and FT‐IR spectroscopic analysis. The results indicated that good yield of nanoparticle vermiculite was achieved when the acid treatment was carried out for 120 h. In addition, the results showed that the presence of DVMT clay improved the chemical bonding in the SBR nanocomposites and hence their mechanical properties. The highest improvement was obtained when the contents of DVMT clay, MA, and irradiation dose were 10 phr, 3 phr, and 100 kGy, respectively. POLYM. ENG. SCI., 59:355–364, 2019. © 2018 Society of Plastics Engineers     

Development of acrylonitrile‐butadiene (NBR)/polyamide thermoplastic elastomeric compositions: Effect of carboxylation in the NBR phase

The current investigation was aimed at assessing the effect of carboxylation of NBR phase in dynamically vulcanized NBR/low‐melting polyamide thermoplastic elastomeric compositions. Improved strength and set properties were achieved because of better compatibilization with carboxylated NBRs. The dispersion of the rubber became homogeneous and finer with increase in the degree of carboxylation. Glass transition studies by DMA and DSC suggested the presence of a compatibilizing block copolymer generated in situ by the reaction between the ? COOH groups in the rubber and the ? NH₂ groups in the polyamide during melt‐mixing. The reaction was studied for a representative 60 : 40 rubber/plastic blend by DSC. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1008–1012, 2006     

Rectorite powder modified by butadiene‐styrene‐vinyl pyridine rubber: Structure and its dispersion in styrene‐butadiene rubber

Rectorite (REC) powders modified by butadiene‐styrene‐vinyl pyridine rubber (VPR) were prepared by spray drying, designated as REC‐VPRs. X‐ray diffraction (XRD), Scanning electron microscope (SEM), and transmission electron microscopy (TEM) analyses showed that in the REC‐VPRs, VPR did not intercalate into the intergallery of layers. However, compared with REC, the layers of REC‐VPRs had more wrinkles and piled loosely. To strengthen the interfacial interaction between VPR and REC, a REC‐VPR was treated by volatilized hydrochloric acid, resulting in the formation of ion bonds between REC and VPR, according to Fourier transform infrared spectra measurements. XRD analyses revealed that the intercalated structure emerged in acid treated REC‐VPR filled styrene‐butadiene rubber (SBR). However, the better dispersion was observed for the SBR composite filled with REC‐VPR without acid treatment, indicating that a proper interfacial interaction between REC and VPR is the key to improve the dispersion of REC layers in SBR. Acid treatment did not improve the tensile and tear strengths of the SBR composite filled with REC‐VPR. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci., 2013     

Preparation and dynamic mechanical properties of poly(styrene‐b‐butadiene)‐modified clay nanocomposites

Polybutyl acrylate (PBA) was intercalated into clay by the method of multistep exchange reactions and diffusion polymerization. The clay interlayer surface is modified, and obtaining the modified clay. The structures of the clay‐PBA, clay‐GA (glutamic acid), and the clay‐DMSO (dimethyl sulfoxide) were characterized using X‐ray diffraction (XRD). The new hybrid nanocomposite thermoplastic elastomers were prepared by the clay‐PBA with poly(styrene‐b‐butadiene) block copolymer (SBS) through direct melt intercalation. The dynamic mechanical analysis (DMA) curves of the SBS/modified clay nanocomposites show that partial polystyrene segments of the SBS have intercalated into the modified clay interlayer and exhibited a new glass transition at about 157°C (T_g3). The glass transition temperature of polybutadiene segments (T_g1) and polystyrene segments out of the modified clay interlayer (T_g2) are about ?76 and 94°C, respectively, comparied with about ?79 and 100°C of the neat SBS, and they are basically unchanged. The T_g2 intensity of the SBS‐modified clay decreases with increasing the amounts of the modified clay, and the T_g3 intensity of the SBS‐modified clay decreases with increasing the amounts of the modified clay up to about 8.0 wt %. When the contents of the modified clay are less than about 8.0 wt %, the SBS‐modified clay nanocomposites are homogeneous and transparent. The T_gb and T_gs of the SBS‐clay (mass ratio = 98.0/2.0) are ?78.39 and 98.29°C, respectively. This result shows that the unmodified clay does not essentially affect the T_gb and T_gs of the SBS, and no interactions occur between the SBS and the unmodified clay. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1499–1503, 2002; DOI 10.1002/app.10353     

Preparation and characteristics of nitrile rubber (NBR) nanocomposites based on organophilic layered clay

The effect of clay modification on organo‐montmorillonite/NBR nanocomposites has been studied. Organo‐montmorillonite/NBR nanocomposites were prepared through a melt intercalation process. NBR nanocomposites were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), dynamic mechanical thermal analysis (DMTA) and a universal testing machine (UTM). XRD showed that the basal spacing in the clay increased, which means that the NBR matrix was intercalated in the clay layer galleries. On TEM images, organo‐montmorillonite (MMT) particles were clearly observed, having been exfoliated into nanoscale layers of about 10–20 nm thickness from their original 40 µm particle size. These layers were uniformly dispersed in the NBR matrix. The DMTA test showed that for these nanocomposites the plateau modulus and glass transition temperature (T_g) increased with respect to the corresponding values of pure NBR (without clay). UTM test showed that the nanocomposites had superior mechanical properties, ie strength and modulus. These improved properties are due to the nanoscale effects and strong interactions between the NBR matrix and the clay interface. Copyright © 2003 Society of Chemical Industry     

Effect of acrylic acid on the properties of recycled poly(vinyl chloride)/acrylonitrile–butadiene rubber blends

The effect of acrylic acid (AAc) on the torque, stabilization torque, mechanical energy, swelling behavior, mechanical properties, thermal stability, and morphological characteristics of recycled poly(vinyl chloride)/acrylonitrile–butadiene rubber (PVCr/NBR) blends was studied. The blends were melt mixed at a temperature of 150°C and rotor speed of 50 rpm. AAc was used to improve the compatibility of PVCr/NBR blends. Virgin PVCv/NBR blends were prepared to provide a comparison. It was found that PVCr/NBR + AAc blends exhibit higher stabilization torque, mechanical energy, stress at peak, and stress at 100% elongation, but lower elongation at break and swelling index than those of PVCr/NBR and PVCv/NBR blends. SEM study of the tensile fracture surfaces of the blends indicated that the presence of AAc increased the interfacial interaction between PVCr and NBR phases, thus improving the compatibility between PVCr and NBR phases. However, thermal gravimetry analysis of the blends showed that the presence of AAc decreased the thermal stability of PVCr/NBR blends. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2181–2191, 2005     

Research of styrene‐butadiene rubber/silicon‐aluminum oxides nanotube binary nanocomposites

A novel silicon‐aluminum oxides (Si‐Al) nanotubes with length ranging from 500 to 1000 nm were introduced to fabricate the styrene‐butadiene rubber (SBR)/Si‐Al nanotube binary nanocomposites. Scanning electron microscope observation showed the Si‐Al nanotubes up to 20 parts per hundred parts of rubber (phr) loading level were dispersed well in SBR matrix. Mechanical properties tests, thermogravimetry analysis and dynamic mechanical thermal analysis revealed that the Si‐Al nanotubes have the effects on improving shore A hardness, tensile strength, tear strength, initial decomposition temperature, and storage modulus while lower the maximum loss factor (tan δ) of the SBR/Si‐Al nanotube binary nanocomposites. FTIR spectra analysis showed that new Si O bond was generated between the hydroxyl group of Si‐Al nanotube and the coupling reagent Si69. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Structure and properties of nitrile rubber (NBR)–clay nanocomposites by co‐coagulating NBR latex and clay aqueous suspension

Nitrile rubber (NBR)–clay nanocomposites were prepared by co‐coagulating the NBR latex and clay aqueous suspension. Transmission electron microscopy showed that the silicate layers of clay were dispersed in the NBR matrix at the nano level and had a planar orientation. X‐ray diffraction indicated that there were some nonexfoliated silicate layers in the NBR–clay nanocomposites. Stress–strain curves showed that the silicate layers generated evident reinforcement, modulus, and tensile strength of the NBR–clay nanocomposites, which were significantly improved with an increase in the amount of clay, and strain‐at‐break was higher than that of the gum NBR vulcanizate when the amount of clay was more than 5 phr. The NBR–clay nanocomposites exhibited an excellent gas barrier property; the reduction in gas permeability in the NBR–clay nanocomposites can be described by Nielsen's model. Compared with gum NBR vulcanizate, the oxygen index of the NBR–clay nanocomposites increased slightly. The feasibility of controlling rubber flammability via the nanocomposite approach needs to be evaluated further. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3855–3858, 2003