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1.
Mercapto‐modified ethylene‐vinyl acetate (EVASH) has been employed as a reactive compatibilizing agent for nitrile‐butadiene rubber (NBR)/ethylene‐propylene‐diene monomer (EPDM) blends vulcanized with a sulfur/2,2′‐dithiobisbenzothiazole (MBTS) single accelerator system and a (sulfur/MBTS/tetramethylthiuram disulfide (TMTD) binary accelerator system. The addition of 5.0 phr EVASH resulted in a significant improvement in the tensile properties of blends vulcanized with the sulfur/MBTS system. In addition to better mechanical performance, these functionalized copolymers gave rise to a more homogeneous morphology and, in some cases, better aging resistance. The compatibilization was not efficient in blends vulcanized with the S/MBTS/TMTD binary system, probably because of the faster vulcanization process occurring in this system. The good performance of these EVASH samples as compatibilizing agents for NBR/EPDM blends is attributed to the higher polarity of these components that is associated with their lower viscosity. Dynamic mechanical analysis also suggested a good interaction between the phases in the presence of EVASH. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1404–1412, 2004  相似文献   

2.
In this study, leather fibers have been used as an additive in several elastomeric compounds based on nitryl butadiene rubber (NBR), chloroprene rubber (CR), ethylene–propylene–diene monomer (EPDM), and chlorinated isobutylene‐isoprene rubber (CIIR). The effects of employing fibers upon vulcanization characteristics, physico‐mechanical and thermal properties of the compounds were studied. Measuring of vulcanization characteristics of the compounds exhibited that leather fibers has no considerable effect on initial viscosity, processability, and curing time of the compounds but increases cross‐link density. Evaluation of mechanical properties of the vulcanized compounds showed that using leather fibers leads to increase in tensile strength of NBR‐based compound due to compatibility between NBR and leather fibers. Also hardness of all compounds increased drastically by employing leather fibers. The obtained results showed incorporation of leather fibers had no considerable effect on resilience, density, and thermal stability of compounds but enhanced liquid resistance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   

3.
Organo‐montmorillonite/nitrile butadiene rubber (OMMT/NBR) nanocomposites were prepared by co‐coagulating process, and then were combined with rubber ingredient and vulcanized by traditional rubber mixing procedure. The SEM micrographs of the nanocomposites showed uniform dispersion of the OMMT particles in NBR. The ATR‐FTIR spectra illustrated the existence of montmorillonite in the nanocomposites. The XRD patterns further indicated the structure of nanocomposites, and confirmed an effective intercalation of NBR in the interlayer space of the OMMT. Moreover, the tensile strength and elongation at break of nanocomposites tended to increased rapidly with increasing OMMT loading, due to the reinforcing properties of OMMT to NBR. In addition, the TGA and DTA curves demonstrated the thermal performance of the nanocomposites enhanced. Furthermore, the addition of OMMT accelerated the vulcanization process. POLYM. COMPOS., 34:1809–1815, 2013. © 2013 Society of Plastics Engineers  相似文献   

4.
Acrylonitrile butadiene rubber (NBR)‐based composites were prepared by incorporating short nylon fibers of different lengths and concentration into the matrix using a two‐roll mixing mill according to a base formulation. The curing characteristics of the samples were studied. The influence of fiber length, loading, and rubber crosslinking systems on the properties of the composites was analyzed. Surface morphology of the composites has been studied using Scanning Electron Microscopy (SEM). Addition of nylon fiber to NBR offers good reinforcement, and causes improvement in mechanical properties. A fiber length of 6 mm was found to be optimum for the best balance of properties. It has been found that at higher fiber loadings, composites show brittle‐type behavior. Composites vulcanized by the dicumyl peroxide (DCP) system were found to have better mechanical properties than that by the sulfur system. The swelling behavior of the composites in N,N‐dimethyl formamide has been analyzed for the swelling coefficient values. Composites vulcanized in the DCP system were found to have higher rubber volume fraction than that in the sulfur system, which indicates better rubber–fiber interaction in the former. The crosslink densities of various composites were also compared. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1023–1030, 2004  相似文献   

5.
Novel rigid poly(vinyl chloride) (PVC)/cross‐linked acrylonitrile butadiene rubber (NBR) blend using copper (II) sulfate pentahydrate (CuSO4·5H2O) as cross‐linking agent was prepared by melt mixing. Fourier transform infrared analysis showed that the coordination cross‐linking occurred between NBR and CuSO4·5H2O in the PVC matrix, in which a novel morphology was first observed by scanning electron microscopy analysis. The thermal stability and degradation behavior of the PVC/NBR/CuSO4·5H2O blend were examined by means of dynamic mechanical thermal analysis and thermogravimetric analysis. It was found that the glass‐transition temperature (Tg) of the PVC/NBR/CuSO4·5H2O blend was enhanced by adding the coordination cross‐linked NBR into the PVC matrix. In spite of the onset decomposition temperature and the first rapidest decomposition temperature of the resultant blends reduced in comparison to neat PVC, the second rapidest decomposition temperature and the residues of the resultant blends were significantly enhanced. In addition, the thermal degradation kinetics and mechanical properties of the resultant blends were also investigated. POLYM. ENG. SCI., 54:1864–1870, 2014. © 2013 Society of Plastics Engineers  相似文献   

6.
The effects of maleic anhydride modified ethylene–propylene–diene rubber (EPDMMA) and maleic anhydride modified ethylene–vinyl acetate (EVAMA) on the compatibilization of nitrile rubber (NBR)/ethylene–propylene–diene rubber (70:30 w/w) blends vulcanized with a sulfur system were investigated. The presence of EPDMMA and EVAMA resulted in improvements of the tensile properties, whereas no substantial change was detected in the degree of crosslinking. The blend systems were also analyzed with scanning electron microscopy and dynamic mechanical thermal analysis. The presence of EVAMA resulted in a blend with a more homogeneous morphology. The compatibilizing effect of this functional copolymer was also detected with dynamic mechanical analysis. A shift of the glass‐transition temperature of the NBR phase toward lower values was observed. The presence of EPDMMA and EVAMA also increased the thermal stability, as indicated by an improvement in the retention of the mechanical properties after aging in an air‐circulating oven. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2408–2414, 2003  相似文献   

7.
In this study, the morphologies of three types of acrylonitrile–butadiene rubber (NBR)/polypropylene (PP) thermoplastic vulcanizates (TPVs) (with an NBR/PP blend ratio of 70/30) were compared. The TPVs were (1) an ultrafine fully vulcanized acrylonitrile–butadiene rubber (UFNBR)/PP TPV made by the mechanical blending of UFNBR with PP, (2) a dynamically vulcanized NBR/PP TPV without the compatibilization of maleic anhydride grafted polypropylene (MP) and amine‐terminated butadiene–acrylonitrile copolymer (ATBN), and (3) a dynamically vulcanized NBR/PP TPVs with the compatibilization of MP and ATBN. The influence of the compatibility therein on the size of the dispersed vulcanized NBR particles and the crystallization behavior of the PP in the TPVs and the resultant properties are also discussed. As indicated by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, polarizing microscopy, dynamic mechanical thermal analysis, and rheological and mechanical testing, the compatibility was significantly improved by the reactive compatibilization of MP and ATBN, which led to a uniform and fine morphology. The compatibilization increased the crystallization rate and reduced the size of the spherulites of PP. On the other hand, it was found that the dispersed vulcanized NBR particles lowered the degree of crystallinity. The better the compatibility of the blend was, the lower the degree of crystallinity and the storage modulus were, but the higher the loss factor and the processing viscosity were. All TPVs showed almost the same oil resistance, but the TPV prepared with reactive compatibilization had the best mechanical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

8.
A model waste nitrile rubber powder (w‐NBR) was prepared by ambient grinding of aged NBR vulcanizate based on an oil seal formulation. The w‐NBR was characterized by scanning electron microscopic and optical microscopic techniques. Virgin nitrile rubber in a thermoplastic elastomeric 70:30 nitrile rubber/poly(styrene‐co‐acrylonitrile) (SAN) blend was replaced by w‐NBR, and the mechanical properties and swelling index were determined. The virgin NBR in the blend was replaced by the rubber present in w‐NBR (r‐w‐NBR) and the optimum mechanical properties were achieved at 45% replacement where the blend was still reprocessable. Transmission electron microscopic and atomic force microscopic studies reveal that w‐NBR particles coated with NBR are dispersed in a continuous SAN matrix. It was observed that migration of unreacted curatives from w‐NBR to virgin NBR is not significant and incorporation of curatives is necessary for attainment of optimum level of mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2348–2357, 2003  相似文献   

9.
Effect of alumina nanoparticle (ANP) on the properties of rubber compounds based on nitrile‐butadiene‐rubber (NBR) and NBR/phenolic‐resin (PH) blend is examined. To investigate the surface characteristics of the nanoparticles on the performance of nanoalumina‐filled compounds, trimethoxyvinylsilane (MVS) is attached chemically on the surface of ANP through an appropriate functionalization process. Various NBR and NBR/PH compounds filled with ANP and functionalized ANP (f‐ANP) are prepared via melt mixing using traditional open two‐roll mill. Microscopic analysis carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveals good dispersion of nanoalumina within the rubber matrix, indicating the effectiveness of the melt mixing for fabrication of the rubber/alumina nanocomposites. Nanocomposites of NBR and NBR/PH are subjected to various physical and mechanical tests including swelling, tensile, abrasion, and thermal tests and the role of ANP and f‐ANP on these properties are discussed. The results obtained based on this analysis suggest that as‐received ANP can provide good interaction with NBR possibly due to hydrogen bonding between hydroxyl group present on the nanoparticle surface and acrylonitrile group of NBR. POLYM. COMPOS., 2009. © 2009 Society of Plastics Engineers  相似文献   

10.
Blends of acrylonitrile butadiene rubber (NBR) and poly(ethylene‐co‐vinyl acetate) (EVA), with varying proportions of the components, were vulcanized using different crosslinking systems, namely, sulfur (S), dicumyl peroxide (DCP), and a mixed system (S + DCP). Mechanical properties, such as stress–strain behavior, tensile strength, elongation at break, Young's modulus, tensile set, and tear strength, were studied. The mixed system exhibited better mechanical performance than other systems. The tensile and tear fracture surfaces were analyzed under the scanning electron microscope in order to understand the failure mechanism. The variation in properties was correlated with the morphology of the system. The effect of high‐abrasion furnace black (HAF), semireinforcing furnace black (SRF), silica, and clay on the mechanical properties and failure mechanism of 50/50 blend of NBR–EVA (N50P) has also been studied. The Kraus equation has been applied to analyze the extent of polymer–filler interaction. Applicability of various theoretical models has been investigated to predict the properties of the blend systems. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2335–2364, 1999  相似文献   

11.
In this article, semi‐interpenetrating polymer network (Semi‐IPNs) based on nitrile rubber (NBR) and poly(methyl methacrylate‐co‐butyl acrylate) (P(MMA‐BA)) were synthesized. The structure and damping properties of the prepared Semi‐IPNs blends were characterized and by fourier transform infrared spectrum (FTIR), dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), thermogravimetric analysis (TGA/DTG), and tensile mechanical properties. The results showed that interpenetrating network based on P(MMA‐BA) and NBR was successfully obtained, which showed the improved thermal stability compared to NBR/P(MMA‐BA)‐based two‐roll mill blends. Furthermore, Semi‐IPNs showed significantly better the dynamic mechanical properties than that of the two‐roll mill system. With the increasing feed ratio of BA and MMA during the preparation of Semi‐IPNs, the loss peak position for P(MMA‐BA) in NBR/PMMA IPNs shifted to a lower temperature from 20°C to ?17°C, and when NBR in Semi‐IPNs was accounted for 40 wt %, the dynamic mechanical thermal analysis showed that much more advanced damping material with wider temperature range (?30°C < T < 80°C) as tan δ > 0.45 can be achieved. Therefore, it was expected as a promising way to obtain the excellent damping materials with good oil‐resisted properties according the Semi‐IPNs system. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40217.  相似文献   

12.
Crosslinked α‐methylstyrene and acrylonitrile (MStAN) copolymer particles in a latex form were synthesized by free radical emulsion polymerization. The particles took a spherical shape with an average size of 53.1 nm in a narrow distribution. When filled into styrene‐butadiene rubber (SBR), nitrile‐butadiene rubber (NBR), and natural rubber (NR), the MStAN nano‐particles exhibited excellent reinforcing capabilities and the best in NBR. By the employment of heat treatment, mechanical properties of the MStAN‐filled SBR composites had got remarkable further improvements. But mechanical properties, together with the morphology, of the MStAN‐filled NBR composites, varied little after heat treatment, which, however, divulged the naturally good compatibility between the MStAN particles and the NBR matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

13.
Acrylonitrile butadiene rubber (NBR)/bentonite (Bt) nanocomposites were synthesized by an one‐step method in NBR latex with (3‐Mercaptopropyl)trimethoxysilane (MPTMS) as a compatilizer. The nanocomposites were compounded with curing additives and then vulcanized. The prepared vulcanizates were characterized by Fourier transform infrared spectroscopy (FTIR) and X‐ray diffraction (XRD). The curing properties and mechanical properties were also investigated. The thermal properties were studied with thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The morphology was investigated by field emission‐scanning electron microscopy (FE‐SEM). By swelling test, the swelling ratio and the crosslinking density were achieved. The hydrolyzation and condensation of MPTMS was identified by FTIR while the intercalated/exfoliated structure of Bt was determined by XRD. It was evident that the mechanical properties of the nanocomposites were significantly improved compared with the neat NBR. The well‐dispersed bentonite particles and effects of MPTMS were supported by the images from FE‐SEM. The results of TGA showed that the fastest weight‐loss temperature (Tmax) was elevated by over 10°C for the nanocomposites compared with the neat NBR, indicating an enhanced thermal stability. By swelling test, the swelling ratio was determined, decreased to 139% for the optimized NBR/MPTMS/Bt nanocomposites compared with 210% for neat NBR. POLYM. COMPOS., 36:1693–1702, 2015. © 2014 Society of Plastics Engineers  相似文献   

14.
Dynamically vulcanized blends of nylon, styrene–acrylonitrile copolymer (SAN), and nitrile–butadiene rubber (NBR) were examined for mechanical properties, Shore D hardness, Vicat softening temperature, impact process, and phase morphology. The effect of a curing system such as phenolic formaldehyde resins (PF), dicumylperoxide (DCP), and a sulfur system on the mechanical properties of the nylon/SAN/NBR blends was studied, and dynamic vulcanization with a PF system was found to lead to outstanding toughness of the blends. The effect of PF content on the mechanical properties, Shore D hardness, and heat resistance of the nylon/SAN/NBR blends was also investigated. With increasing PF content the notched‐impact strength and Vicat softening temperature (VST) of the nylon/SAN/NBR (50/25/25) blends evidently improved, but tensile strength and Shore D hardness of the blends changed slightly. It can be concluded that the nylon/SAN/NBR (50/25/25) blends dynamically vulcanized by high‐content PF can attain excellent comprehensive mechanical properties, especially supertoughness, at room temperature. SEM was used to investigate the effect of dynamic vulcanization on disperse‐phase particle size, particle size distribution, and phase morphology. It was obvious that disperse‐phase particle size decreased with an increasing PF content. Thermal behavior and miscibility of dynamically vulcanized nylon/SAN/NBR with PF were investigated by DMTA. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2057–2062, 2003  相似文献   

15.
Elastomeric composites based on nitrile rubber (NBR), carbon black (CB), and organically modified nanoclay (NC) were prepared using a laboratory two‐roll mixing mill. Influences of the hybrid filler system (CB+NC) on various properties of NBR compound were analyzed. It was found that the addition of hybrid filler (CB+NC) over only carbon black enhances various properties. It was also found that the addition of nanoclay to the rubber matrix effectively improved key properties. Acoustics and electrical properties were modified with reduced water absorption because of layered clay platelets. The lower volume resistivity of NBR composites reflected better electrical conductivity attributed to the presence of nanoclay leading to effective filler connectivity. X‐ray diffraction and transmission electron microscopy measurements revealed that nanoclays were mostly intercalated and were uniformly dispersed. Use of calcium stearate facilitated dispersion of nanoclay in the rubber matrix which was observed through the formation of nanostructures including “nano” and “halo” units. Time temperature superposition in dynamic mechanical analysis test of the composites indicated lower mechanical loss in the frequency range of interest. The advantages accruing due to overall property enhancement, including lower water absorption, and better electrical and excellent acoustic properties of NBR composites make it suitable as underwater acoustic transparent materials for transducer encapsulation application. POLYM. COMPOS., 37:1786–1796, 2016. © 2014 Society of Plastics Engineers  相似文献   

16.
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  相似文献   

17.
The basic material used in this work was a low‐molecular‐weight polybutadiene with isocyanate endgroups in the main chain. The isocyanate groups were used for crosslinking of the oligomeric polybutadiene with glycerol as a three‐functional crosslinker. The prepared polybutadiene‐based polyurethane gel was subsequently vulcanized with sulphur. The effect of sulphur content on mechanical and electrical properties of resulting materials was investigated with the aim to find an optimum matrix composition for the preparation of composite materials. Several types of glass fiber fabric reinforcement differing in fabric weight and fabric ply thickness were tested. Mechanical properties of composites based on the optimum matrix composition and different types of glass fibers were measured and compared. Being vulcanized with sulphur, the polybutadiene was found to possess improved mechanical properties and retain an excellent electroinsulating character. Moreover, the sulphur‐vulcanized polybutadiene was proved good as a matrix for the preparation of glass fiber‐reinforced composite materials having enhanced tensile and flexural properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   

18.
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  相似文献   

19.
The effects of dynamic vulcanization and blend ratios on mechanical properties and morphology of thermoplastic elastomeric (TPE) compositions, based on blends of nitrile rubber (NBR) and poly(styrene‐co‐acrylonitrile) (SAN), were studied. The TPE composition prepared by adding a rubber‐curatives masterbatch to softened SAN yields higher mechanical properties than that prepared by adding curatives to the softened plastic–rubber preblend. The blends having a higher rubber–plastic ratio (60 : 40 to 80 : 20) display thermoplastic elastomeric behavior, whereas those having a higher plastic–rubber ratio (50 : 50 to 90 : 10) display the behavior of impact‐resistant plastics. DSC studies revealed that NBR and SAN are thermodynamically immiscible. SEM studies of the thermoplastic elastomeric compositions show that SAN forms the matrix in which fine particles of NBR form the dispersed phase. It was further confirmed by dynamic mechanical thermal analysis. Dynamic vulcanization causes a decrease in the size of dispersed particles and improvement in mechanical properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1976–1987, 2003  相似文献   

20.
The phenolic resin (PF) was incorporated into acrylonitrile–butadiene rubber (NBR) vulcanizates by in situ polymerization during the vulcanization process. It was found that the tensile strength, tearing strength, and tensile strength (300% elongation) could be considerably enhanced 59.4, 80.2, and 126.4%, respectively, at an optimum PF content of only 15 phr, but the elongation at break and shore A hardness were only slightly affected on the basis of silica‐reinforced NBR vulcanizates. A systematic study of the PF structure formed within the NBR matrix using various experimental schemes and procedures has revealed that the PF resin would form the localized discontinuous three‐dimensional interconnected network structures in the NBR matrix. The substantial reinforcement of PF on the mechanical properties of vulcanized NBR were attributed to the morphology, high flexibility, and moderate stiffness of the PF phases and their excellent bonding with rubbers through “rubber to rubber” and interface layer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007  相似文献   

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