Aramid pulp with physisorbed imidazolium ionic liquids for solvent‐casted enhanced styrene‐butadiene rubber composites

Poly‐p‐phenyleneterephthalamide is a broadly used aramid for the strengthening of materials. Nevertheless, its relatively inert surface is an obstacle for obtaining composites with enhanced properties. In this work, three ionic liquids (IL) were investigated as compatibilizers in the preparation of styrene‐butadiene rubber (SBR)‐aramid pulp composites. The composites were characterized using hardness and tensile tests, swelling, differential scanning calorimetry, and thermal gravimetric analysis, and also scanning electron microscopy. Aramid pulp treated with IL showed more fibrillation than the untreated pulp. The best characteristics were found for the composite with 5 phr of aramid pulp‐1 wt % of physisorbed IL, which showed the lowest swelling degree compared to the IL‐free SBR‐aramid composite (341% and 410%, respectively) and the highest tensile strength (2.48 MPa), 340% superior to that of SBR (0.73 MPa), and 25% superior to the IL‐free SBR‐aramid composite (2.05 MPa). Confirming the potential of imidazolium IL to be used as compatibilizers in SBR‐aramid composites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46693.     

Effect of filler geometry on viscoelastic damping of graphite/aramid and carbon short fiber‐filled SBR composites: A new insight

An investigation on the effect of filler geometry/shape on the dynamic mechanical properties of polymers was conducted. The viscoelastic damping matrix chosen was SBR and the fillers chosen were graphite, aramid, and carbon short fibers. The study was conducted by taking a control base compound of 20 parts N330 carbon black‐filled styrene butadiene rubber (SBR). Dynamic mechanical thermal analyzer was used to investigate the viscoelastic damping of the rubber composites at low dynamic strain levels. Compressive hysterisis at moderate degree of strain were evaluated for all the composite samples to probe into their high strain static damping properties. SEM was used to investigate the matrix‐fiber interaction and distribution of the fillers. Investigations demonstrated that the matrix‐filler interface plays a major role in energy dissipation. The amount of interface was analyzed by considering the half height width of tan δ peak. Fiber matrix interaction parameter was calculated from the tan δ_max values for matrix and composite. It was observed the interaction parameter and the low strain tensile stress values register similar trend. Aramid short fibers were most effective in more energy dissipation than other fillers under consideration. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

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     

等离子体处理对芳纶帘线/橡胶复合材料界面的影响

研究了等离子体的处理功率、处理时间和气氛以及芳纶帘线浸胶处理与否对芳纶帘线／橡胶复合材料界面的影响。结果表明,经过等离子体处理后,未浸胶芳纶帘线在H抽出时发生界面破坏,而结合浸胶处理．H抽出时破坏由橡胶基体逐步向芳纶帘线发展,橡胶基体能有效地通过界面向芳纶帘线表面传递应力;最佳的等离子体处理条件是在空气气氛中,处理功率为50w,处理时间为5min。     

Polyurethane/conducting carbon black composites: Structure,electric conductivity,strain recovery behavior,and their relationships

The polyurethane composites with conducting carbon black (CB) were prepared by a solution‐precipitation process, which was followed by melt compression molding. The polyurethane used has good shape memory effect. The morphology of CB fillers in polyurethane matrix and the resulting conductivity of the composites were investigated. It has been found that CB fillers exist in the forms of aggregates. The percolation threshold is achieved at the CB concentration of 20 wt %. The presence of CB fillers decreases the degree of crystallinity of polycaprolactone (PCL) soft segments of the polyurethane. However, the composites still have enough soft‐segment crystals of polyurethane to fulfil the necessary condition for the shape memory properties. Dynamic mechanical data show that CB is an effective filler for the reinforcement of the polyurethane matrix, but does not deteriorate the stable physical cross‐link structure of the polyurethane, which is necessary to store the elastic energy in the service process of the shape memory materials. Addition of CB reinforcement in the polyurethane has influenced the strain recovery properties, especially for those samples with CB concentrations above the percolation threshold. The response temperature of the shape memory effect T_r has not been affected too much. Strain fixation S_f, which expresses the ability of the specimens to fix their strain, has been improved in the presence of the CB fillers. The final recovery rates R_f and strain recovery speeds V_r of the shape memory measurements, however, have decreased evidently. It is expectedly ascribed to the increased bulk viscosity as well as the impeding effect of the inter‐connective structure of CB fillers in the polymer matrix. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 68–77, 2000     

离子液体改性无机材料制备橡胶导热助剂

通过研究[C4mim]Br、[C7mim]Br、[C8mim]Br、[BPy]Br共4种离子液体对白炭黑、膨润土、高岭土、硅藻土、珍珠岩（深、浅色）共6种不同无机材料进行改性,并对改性前后的无机材料进行了FT-IR、TG和氮气吸附-脱附比表面积分析。应用改性后的无机材料与橡胶混炼制胶,测定其导热系数。结果表明,无机材料经离子液体改性后均比未改性的导热系数有所提高,其中,[C4mim]Br改性无机材料的导热系数提高幅度最大,[C4mim]Br改性的高岭土的导热系数高达0.389W/(m?K),与改性前的导热系数相比提高了89.76%。     

导电复合橡胶用导电填料的应用研究进展

对导电复合橡胶用导电填料如炭系、金属系、颗粒表面镀金属等的种类、性质等因素对复合橡胶材料导电率的影响及应用进行了综述。也对采用新型的填料即本征导电聚合物主要是聚苯胺填充制备导电复合橡胶的研究进展进行了综述。炭系是目前制备导电复合橡胶主要的导电填料,但有污染,不适合制备有颜色要求的导电材料,金属系、颗粒表面镀金属的比重大,在聚合物中分散较困难,也不太适合于有比重要求的制品。本征导电聚合物导电填充填料是制备导电复合橡胶发展的一个重要方向,可以解决不熔难溶造成的在聚合物中分散性差的问题。     

Dielectric and microwave properties of elastomer composites loaded with carbon–silica hybrid fillers

In this study, we investigated the influence of carbon–silica dual‐phase fillers on the dielectric and microwave properties of natural‐rubber‐based composites determined in the frequency range from 1 to 12 GHz. The fillers were prepared by the impregnation of two types of carbon black with various silicasol amounts. As the results show, the fillers affected both the dielectric and microwave properties of the obtained composites. The higher the quantity of the dielectric phase (silica) in the hybrid filler was, the lower the real part of the permittivity of the composites was. This caused changes in the total, reflective, and absorptive shielding effectivenesses of the latter and their reflection and attenuation coefficients. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42978.     

Effect of imidazolium ionic liquid type on the properties of nitrile rubber composites

We investigated the influence of hydrophilic and hydrophobic imidazolium ionic liquids on the curing kinetic, mechanical, morphological and ionic conductivity properties of nitrile rubber composites. Two room temperature ionic liquids with a common cation—1‐ethyl‐3‐methylimidazolium thiocyanate (EMIM SCN; hydrophilic) and 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM TFSI; hydrophobic)—were used. Magnesium–aluminium layered double hydroxide (MgAl‐LDH; also known as hydrotalcite) was added to carboxylated acrylonitrile–butadiene rubber (XNBR) whereas fumed silica Aerosil 380 was used in acrylonitrile–butadiene rubber (NBR) as reinforcing fillers. NBR compounds were vulcanized with a conventional sulfur‐based crosslinking system whereas XNBR compounds were cured with MgAl‐LDH. The optimum cure time reduction and tensile properties improvement were obtained when both ionic liquids were added at 5 parts per hundred rubber (phr). The results revealed that EMIM SCN and EMIM TFSI induced an increase in the AC conductivity of nitrile rubber composites from 10^?10 to 10^?8 and to 10^?7 S cm^?1, respectively (at 15 phr ionic liquid concentration). The presence of ionic liquids in NBR slightly affected the glass transition temperature (T_g) whereas the presence of EMIM TFSI in XNBR contributed to a shift in T_g towards lower temperatures from ?23 to ?31 °C, at 15 phr loading, which can be attributed to the plasticizing behaviour of EMIM TFSI in the XNBR/MgAl‐LDH system. Dynamic mechanical analysis was also carried out and the related parameters, such as the mechanical loss factor and storage modulus, were determined. © 2013 Society of Chemical Industry     

Influence of carbon black in polychloroprene organoclay nanocomposite with improved mechanical,electrical and morphology characteristics

Abstract

The effect of carbon black on nanoclay filled polychloroprene (CR) composites has been investigated. The nanoclay loading is fixed at 5 part per hundred rubbers (phr), and carbon black loading varied from 5 to 20 phr in rubber compounds. The rubber nanocomposites are prepared in laboratory by mixing in two-roll mill. The addition of nanoclay enhances mechanical properties especially tear strength and decreases water absorption without change in electrical properties compared to gum rubber vulcanisates. Wide angle X-ray diffraction and transmission electron microscopy are used to study the microstructure of CR nanocomposites. The addition of 5 parts of nanoclay to 15 phr carbon black filled samples shows synergistic effect between the fillers and suggests that the reinforcement is due to a more developed filler network formation in hybrid filler system than that in single phase filler. Significant improvement in mechanical, electrical and low water absorption properties has been obtained with these nanoclay and carbon black filled rubber nanocomposites. The paper concludes that nanocomposites containing a mixture of organoclay and carbon black in right proportion can be a substitute for rubber components used in underwater cable and device encapsulation applications.     

Mechanical properties and reinforcement mechanisms of hydrogenated acrylonitrile butadiene rubber composites containing fibrillar silicate nanofibers and short aramid microfibers

Short‐fiber‐reinforced rubber composites (SFRCs) with hydrogenated acrylonitrile butadiene rubber (HNBR) as the matrix and fibrillar silicate (FS) nanofibers and short aramid microfibers (DCAFs) as the fillers were developed, and their tensile properties, compression moduli, and mechanical anisotropies were investigated. The results indicated that the properties of the HNBR/DCAF/FS composites were determined by the loadings of the FS nanofibers and DCAF microfibers. A small amount of the microfibers combined with an appropriate amount of the nanofibers resulted in synergetic reinforcement and imparted to the SFRCs significantly improved mechanical properties without substantially compromising the rubbery characteristics. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Improvement in physical and electrical properties of poly(vinyl alcohol) hydrogel conductive polymer composites

With an aim to develop anti‐electrostatic discharge materials based on biodegradable polymers, poly(vinyl alcohol) films composited with two different conductive fillers (carbon black and aluminium) at various fillers contents (20?60%wt), were manufactured using solvent‐casting technique. The mechanical properties of such the films were investigated through tensile stress‐strain tests. Wettability and morphology of the composite films were performed by water contact angle measurement and SEM, respectively. Young's modulus of the composite films can be increased with the addition of conductive fillers. The surface of the composite films showed non‐homogeneous appearance, in which the phase boundary within the composites was clearly observed and the conductive fillers formed aggregation structure at high filler concentration. In addition, the composite films exhibited better hydrophobicity when higher conductive filler content was added. TGA results suggested that both carbon black and aluminum have proven their efficiency to enhance thermal stability of poly(vinyl alcohol). Investigation of cross‐cut adhesion performance of the prepared composite films revealed that carbon black‐filled composites exhibited excellent adhesion strength. The effect of conductive filler content on surface resistivity of the composite films was also examined. The experimental results confirmed that both the fillers used in this study can improve the electrical conductivity of poly(vinyl alcohol) hydrogel. The surface resistivity of the composite films was reduced by several orders of magnitude when the filler of its critical concentration was applied. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42234.     

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.     

In situ dispersion and compatibilization of lignin/epoxidized natural rubber composites: reactivity,morphology and property

Lignin, a naturally occurring polymer, was viewed as a potential substitute of carbon black for reinforcing rubber materials. However, it shows no reinforcing effect if directly mixed with rubber. In this study, lignin was in situ dispersed at submicrometer size and highly compatible with epoxidized natural rubber (ENR) by using a high‐temperature dynamic heat treatment (HTDHT). Rheology analysis indicated that the ring opening reaction between lignin and ENR occurred at 160°C or above, which was further confirmed by infrared spectroscopy. Due to the consumption of acidic groups of lignin by ENR, the retardant vulcanization effect of lignin was weakened. Morphology observation and dynamic mechanical analysis demonstrated the perfect lignin dispersion and the strong interactions between lignin and ENR. The mechanical properties of the lignin/ENR composites were significantly improved by using HTDHT. Compared to the directly mixed rubber composites, the tensile strength and tear strength of the heat treated rubber composites filled with 40 phr lignin were increased by 114% and 23%, respectively. Especially, the 300% modulus of the heat treated rubber composite was increased by ca. 400%. X‐ray diffraction results indicated that the reinforcement of the composites originated from the presence of lignin rather than the strain‐induced crystallization of ENR. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42044.     

Viscoelastic properties of natural rubber composites reinforced by defatted soy flour and carbon black co‐filler

Filler mixtures of defatted soy flour (DSF) and carbon black (CB) were used to reinforce natural rubber (NR) composites and their viscoelastic properties were investigated. DSF is an abundant and renewable commodity and has a lower material cost than CB. Aqueous dispersions of DSF and CB were first mixed and then blended with NR latex to form rubber composites using freeze‐drying and compression molding methods. A 40% co‐filler reinforced composite with a 1 : 1 DSF : CB ratio exhibited a 90‐fold increase in the rubber plateau modulus compared with unfilled NR, showing a significant reinforcement effect by the co‐filler. The effect, however, is lower than that observed in the carboxylated styrene–butadiene rubber composites reported earlier, indicating a significant effect from the rubber matrix. The co‐filler composites have elastic moduli between those of DSF and CB reinforced composites. Stress softening and recovery experiments indicated that the co‐filler composites with a higher CB content tend to have a better recovery behavior; however, this can not be simply explained from the recovery behaviors of the single filler (DFS and CB) composites. CB composites prepared by freeze‐drying show a strain‐induced reorganization of fillers. Strain sweep experiment data fit with the Kraus model indicates the co‐filler composites with a higher CB content are more elastic, which is consistent with the recovery experiments. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Flow properties of natural rubber composites filled with defatted soy flour

The linear and nonlinear viscoelastic properties of natural rubber composites reinforced with defatted soy flour (DSF) were studied. DSF is an abundant, renewable commodity, and its rigid nature makes it suitable as a reinforcement phase in rubber composites. At small strain, the elastic modulus of a 30% filled composite was about 20 times higher than the unfilled rubber. Greater reinforcement was observed for carbon black filled composites than for DSF filled composites at filler concentrations of 10 and 20%. At high strain, values of the relaxation modulus dropped more rapidly for highly filled DSF composites. At high shear rates in a capillary viscometer, a small reinforcement effect remained for all composites, and lower die swell was observed for DSF composites. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

芳纶浆粕纤维对CR基质补强特性的研究

对比研究未处理芳纶浆粕和芳纶浆粕预分散体以及不同品种芳纶浆粕纤维补强CR复合材料的微观结构形态及芳纶浆粕纤维对CR基质的补强特性。结果表明,芳纶浆粕对基质橡胶补强潜力的发挥取决于超细纤维在基质橡胶中的分散均匀性、伸展性和取向性,芳纶浆粕纤维对基质橡胶在常温和高温下都具有很高的模量补强效率。     

Dynamic mechanical properties of styrene‐butadiene composites reinforced by defatted soy flour and carbon black co‐filler

Carboxylated styrene‐butadiene (SB) composites reinforced by a mixture of defatted soy flour (DSF) and carbon black (CB) were investigated in terms of their dynamic mechanical properties. DSF is an abundant renewable commodity and has a lower cost than CB. DSF contains soy protein, carbohydrate, and whey. Aqueous dispersions of DSF and CB were first mixed and then blended with SB latex to form rubber composites using freeze‐drying and compression molding methods. At 140°C, a single filler composite reinforced by 30% DSF exhibited roughly a 230‐fold increase in the shear elastic modulus compared to the unfilled SB rubber, indicating a significant reinforcement effect by DSF. Mixtures of DSF and CB at three different ratios were investigated as co‐fillers. Temperature sweep experiments indicate the shear elastic moduli of the co‐filler composites are between that of DSF and CB composites. Strain sweep experiments were used to study the fatigue and recovery behaviors of these composites. Compared with the DSF composites, the recovery behaviors of the 30% co‐filler composites after the eight consecutive deformation cycles of dynamic strain were improved and similar to that of 30% CB composite. Strain sweep experiments also indicated that the co‐filler composites have a greater elastic modulus than the CB reinforced composites within the strain range measured. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Carbon black modified with 4-hydroxymethylbenzenediazonium salt as filler for phenol-formaldehyde resins and abrasive tools

Although phenol-formaldehyde (PF) resins possess excellent properties, they emit toxic substances during the decomposition of the crosslinking agent. Therefore, studies are being carried out on the fillers, which can reduce the amount of crosslinking agent. In this article, the synthesis of diazonium-modified carbon black was conducted. Diazonium modification allows the effective incorporation of hydroxymethyl groups, which are responsible for the crosslinking of PF resins. Modified materials were used as active fillers in the PF composites and abrasive tools. Due to carbon modification, flexural strength increases 26% for PF resin composite and 1100% for abrasive tools. The increase is related to the resulting covalent bonds between the resin and the modified filler. Therefore, it can be stated that application of active filler improves the properties of novolac composites and abrasive tools. The use of this type of fillers may affect the reduction of the amount of crosslinking agent in the future. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48160.     

Thermal and mechanical enhancement of styrene–butadiene rubber by filling with modified anthracite coal

Anthracite is the highest rank of coal with a layered structure similar to that of graphite. Here, styrene–butadiene rubber/modified anthracite (MA) composites were prepared and analyzed. The microstructure and dispersion of the anthracite were improved by ball milling with the modifier bis-(γ-triethoxysilylpropyl)-tetrasulfide (KH-Si69). The particle size of the modified coal was decreased significantly to ~3 μm, while surface interactions with the modifier yielded enhanced lamellar morphology and hydrophobic surfaces. The anthracite lamellae were well dispersed in the rubber matrix, providing good reinforcement; the tensile strength of the composite exceeded that of a composite with carbon black (CB) N660 filler (16.65 vs. 14.68 MPa). Moreover, low-level CB or silica compositing further promoted the dispersion of coal particles in the rubber, effectively enhancing the mechanical reinforcement behavior of the coal particles as well as the thermal stability of the rubber composite. Notably, it led to a 10.63% improvement in tensile strength and a 9.96 °C increase in the 5% mass loss temperature compared to the composite with a single MA filler. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48203.