丁腈橡胶共聚改性酚醛树脂

通过丁腈橡胶与酚醛树脂共聚反应 ,研究了丁腈橡胶的用量对酚醛树脂冲击强度、软化点、凝胶时间的影响 ,尤其是对酚醛树脂增韧的影响。当丁腈橡胶用量仅为 2 %时 ,就可使酚醛树脂的冲击强度提高 10 0 % ,当进一步增加丁腈橡胶用量时 ,冲击强度进一步增加。     

Enhanced oil resistance and mechanical properties of nitrile butadiene rubber/lignin composites modified by epoxy resin

This is probably the first report on developing nitrile butadiene rubber (NBR) composites with enhanced performance s via lignin bridged epoxy resin in the rubber matrix. NBR/lignin masterbatch has been prepared through latex‐compounding method, and then epoxy resin (F51) was added in the NBR/lignin compounds by the melt compounding method. Lignin‐epoxy resin networks were synthesized in situ during the curing process of rubber compounds through epoxide?hydroxyl reactions. Compared with lignin filler, lignin‐F51 networks showed an improved oil resistance ability and led to increased mechanical properties, crosslinking density, and thermal stability of the rubber composites. This method provides a new insight into the fabrication of novel interpenetrating polymer networks in rubber composites and enlarges the potential applications of lignin in high performance rubber composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42922.     

Synthesis and properties of biophenol-furfural based bioresin for curing of styrene butadiene rubber

In the present work, biophenol and furfural-based resol resin was synthesized and utilized for the very first time to cure styrene butadiene rubber (SBR). The reaction was studied over a range of times, temperatures, pH, and furfural to biophenol ratios to fix the optimum conditions. Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy revealed the functional groups and chemical structure of the synthesized resin, respectively. An exothermic peak for the resin curing appeared at 143°C in the differential scanning calorimetry thermogram of the resin. Then, the biophenol-furfural resin was utilized for the curing of SBR. The synthesized resin increased the tensile strength of the raw rubber from 0.20 ± 0.01 MPa to 1.22 ± 0.10 MPa at 10 phr loading, and the crosslink density was 2.56 × 10⁻⁵ mol/mL. The activation energy for curing SBR containing 10 phr resin was 97 kJ/mol. The storage modulus of the resin-cured compound was improved. The glass transition temperature of the raw SBR was also shifted from −43.8 to −42.3°C when 10 phr resin was used for the curing. Hence, for the first time, this work reported the utilization of biophenol-biosourced furfural resin to cure rubbers.     

Impacts of interfacial interaction on properties of melamine formaldehyde microsphere/rubber: I. filler dispersion and curing dynamic

Melamine formaldehyde microsphere (MF) was incorporated into nitrile butadiene rubber (NBR) and styrene butadiene rubber (SBR), respectively. The interaction between MF and rubber and effects of interfacial interaction on the dispersion of filler in rubber matrix, dynamic mechanical analysis, vulcanisation characteristics and kinetics were studied. The results showed that MF interacted with NBR through hydrogen bonds while there had no observed interaction between MF and SBR. The parameter b of MF/NBR calculated by the ratio of modulus and strains increased significantly, which demonstrated further the strong interaction between MF and NBR. For MF/SBR system, however, the parameter b changed slightly with little polymer–filler interaction. The Scanning Electron Microscope images released that strong polymer–filler interaction caused the uniform dispersion of MF in NBR matrix. The vulcanisation of MF/rubber was fitted by Ghoreishy’s model, and the addition of MF increased the rate of curing, shear modulus of compound and activity energy.     

Comparisons of the cure of phenol–formaldehyde novolac and resol systems by differential scanning calorimetry

Comparisons were made of differential scanning-calorimetric (DSC) thermograms of both liquid and powdered commercial phenol–formaldehyde resins. By a combination of the results from analyses under a variety of conditions, such as ambient pressure, high pressure, using freeze-dried samples, and also by direct observation of the resin-curing process in wood-veneer assemblies, the curing reactions of phenol–formaldehyde resins were found to differ for resol and novolac systems. At a heating rate of 10°C/min, the resol resin showed endothermic curing reactions at temperatures of about 150°C, while the novolac-type resin showed an exothermic peak maximum at about 160°C. Results are presented to show how DSC can be used to differentiate between a resol and novolac system.     

Wood flour: A new filler for the rubber processing industry. III. Cure characteristics and mechanical properties of nitrile butadiene rubber compounds filled by wood flour in the presence of phenol‐formaldehyde resin

Nonmodified and corona‐activated conifer wood flour was evaluated as filler to nitrile butadiene rubber (NBR) compounds containing different amounts of phenol‐formaldehyde resin (PFAR) by studying the cure characteristics and the mechanical properties of the filled compounds. It was found that the PFAR affects considerably the cure characteristics and the mechanical properties of the wood flour–filled NBR compounds due to a presumable action as an interface interactions modifier. Acting as an antiaging agent it improves also their thermal‐oxidative stability. The optimal amount of PFAR regarding the cure characteristics and mechanical parameters is of 15 phr/100 phr wood flour. The addition of PFAR just before the wood flour is preferable because of both its better homogenization in the rubber matrix and its lower adsorption by the wood flour, leading to an improvement of the mechanical properties of the wood flour–filled NBR compounds. The replacement of nonmodified wood flour by corona‐activated wood flour leads to additional increase of the mechanical parameters without significant affect of the optimum cure time, aging resistance, and water adsorption. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 95–101, 2004     

丁腈橡胶增韧环氧树脂的性能研究

采用固体丁腈橡胶（NBR）对环氧树脂（EP）进行增韧改性,并对改性后的树脂性能进行了表征。结果显示环氧树脂的韧性随着丁腈橡胶含量的提高而提高,在15%时达到最好。固化剂的用量会对树脂的力学性能有影响,90%是最佳用量。无机填料的加入对树脂的冲击强度和拉伸强度有较大幅度的提高。     

AS/NBR/HSB三元共混体系的动态硫化

采用动态硫化方法制备了丙烯腈-丁二烯共聚物/丁腈橡胶/高苯乙烯树脂（AS/NBR/HSB）三元共混热塑性弹性体，研究了NBR中丙烯腈质量分数，橡塑比和硫化剂对共混体系性能的影响。结果表明，动态硫化显著提高了共混材料的拉伸强度和扯断伸长率，酚醛树脂是AS/NBR，HSB共混体系比较理想的动态硫化交联剂；采用HSB，NBR，AS三元共混，共混材料的拉伸强度和扯断伸长率得到良好的平衡；差示扫描量热分析表明，该三元共混材料具有NBR和AS两相的玻璃化转变温度，说明该体系是典型的不相容体系。     

Reactive compatibilization of a nitrile rubber/phenolic resin blend: Effect on adhesive and composite properties

Resole phenolic resins containing various p-cresol (PC) to phenol (P) mol ratios were prepared and characterized. These phenolic resins were blended with nitrile rubber (NBR) and the measurements of adhesive joint strength, stress–strain properties, DSC, TGA, DMA, TEM, and SEM were performed using a 50 : 50 NBR/phenolic resin blend. It was observed that the adhesive joint strength and the mechanical properties of the blend enhanced significantly on incorporation of p-cresol into the phenolic resin, and the optimum p-cresol/phenol mol ratio was in the vicinity of 2 : 1. Observation of a more continuous phase and the increase in T_g of the rubber region in the blend indicated increased reactivity and compatibilization of NBR with phenolic resin as p-cresol was incorporated. The effect of silica filler on the properties of the nitrile rubber/phenolic resin blend was also studied without and with p-cresol modification and the results suggest that silica filler take not only the role of a reinforcing filler in the nitrile–phenolic–silica composite, but also a role as surface compatibilizer of the blend components. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 1187–1201, 1998     

Study of carbon black distribution in BR/NBR blends based on damping properties: Influences of carbon black particle size,filler, and rubber polarity

Effects of filler and rubber polarity on the distribution of filler in butadiene/nitrile rubber (BR/NBR) blends were investigated, using the dynamic mechanical thermal analysis technique. As 30-phr filler is added, the reduction in heights of damping peaks (tan δ_max), attributed to the dilution effect, was observed. It was also found that the BR phase in the blends, compared to the NBR phase, is more preferential for small- and large-particle size carbon blacks to reside, probably because of the lower viscosity and lower polarity of the BR phase. The addition of silica instead of carbon black leads to an increase in filler migration to the NBR in the 20/80 BR/NBR blend, which is attributed to the strong silica–NBR interaction. In addition, an increase in NBR polarity promotes carbon black migration to the BR phase. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3198–3203, 2001     

Polymer blends of carboxylated butadiene‐acrylonitrile copolymer (nitrile rubber) and polyamide 6 developed in twin screw extrusion

Polymer blends of carboxylated butadiene‐acrylonitrile copolymer (nitrile rubber) and polyamide 6 (PA6) were developed in twin screw extrusion. The rubber was cured with SP 1045 methylol phenolic resin during melt mixing in twin screw. Effect of degree of carboxylation in the rubber phase on blend properties has been assessed. Phase morphologies have been characterized using transmission electron microscopy. A compatibilizing NBR‐g‐Nylon 6 graft copolymer generated in situ during melt mixing via interfacial reaction between the ? COOH groups in NBR and the ? NH₂ end groups in nylon 6 has been effective in generating a fine and stable dispersion of the rubber within the polyamide matrix. The graft copolymer has been characterized by DMTA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 372–377, 2007     

双马来酰亚胺树脂在NBR中的应用研究

研究了交联活性剂N,N-间苯撑双马来酰亚胺树脂（MPBM）对丁腈橡胶（NBR）过氧化物硫化体系中硫化反应的影响,结果表明,MPBM使胶材耐热氧老化性能提高。MPBM用量为3份以下时,硫化反应表观活化能（Ea)随MPBM用量增大而减小;当MPBM用量达到4份时,Ea升高,傅里叶变换红外光谱分析表明,MPBM与NBR发生了共交联反应。     

Synthesis and characterization of polymeric plasticizer from PET waste and its applications in nitrile rubber and nitrile–PVC blend

Polyethylene terephthalate (PET) waste is not biodegradable; thus, it will create environmental hazards if disposed in landfills. Therefore, the only way of addressing the problem of disposal of post-industrial and post-consumer PET wastes is through recycling. The polyester plasticizer for polyacrylonitrile butadiene rubber (NBR) and polyacrylonitrile butadiene–polyvinylchloride rubber blend (NBR–PVC) was obtained by the depolymerization of PET waste with 2-ethyl-1-hexanol. The PET waste was depolymerized until a polymeric plasticizer with the average molecular weight in the range of 450–900 g/mol was obtained. The polymeric plasticizer was characterized for acid and hydroxyl numbers, viscosity, density, FTIR, NMR and TGA/DTA thermogram. The prepared polymeric plasticizer was used in the preparation of nitrile rubber and nitrile–PVC rubber blend rubber sheets, where these sheets were tested for compatibility, tensile strength, elongation-at-break, hardness and ageing properties. Nitrile rubber and nitrile–PVC blend sheets were also prepared using DOP as a plasticizer and a comparative study with the synthesized polymeric plasticizer was made. It was observed that synthesized polymeric plasticizer provides excellent tensile properties and ageing resistance for high-performance applications as compared to that obtained from DOP. The end uses for nitrile rubber and nitrile–PVC rubber blend compounds are quite diverse, but they can be loosely categorized as being either general performances or higher performance applications. Each of these performance categories requires a different set of considerations in terms of compounding with plasticizers.     

Influence of curing agent and compatibilizer on the physicomechanical properties of polypropylene/nitrile butadiene rubber blends investigated by positron annihilation lifetime technique

A series of thermoplastic vulcanizates of polypropylene (PP)/nitrile butadiene rubber (NBR) (50/50) have been prepared by melt‐mixing method, using phenolic resin/SnCl₂ as the curing system and maleic anhydride‐functionalized PP (PP‐g‐MA) and carboxylated NBR (NBRE‐RCOOH) as the compatibilizing system. Triethylenetetramine was also employed to promote the reaction between the functionalized polymers. The effects of curing agent and compatibilizer on the mechanical and morphological properties have been studied. A novel technique based on positron annihilation lifetime spectroscopy has been used to measure the free volume parameters of these systems. The positron results showed minimum free volume size and free volume fraction at 5.0% of the curing agent suggesting some crosslinking in the rubber phase. The reduction in free volume holes at 2.5% of the compatibilizer is interpreted as improvement in the interfacial adhesion between the components of the blend. The observed variation of free volume fraction is opposite to the tensile strength and exhibits the correlation that, lesser the free volume more is the tensile strength at 2.5% of the compatibilizer in the blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4672–4681, 2006     

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     

Studies on conductivity of acrylonitrile‐butadiene rubber/LiClO4 composite and its modification by adding epoxy resin

Solid polymer electrolytes based on acrylonitrile‐butadiene rubber (NBR) and LiClO₄ were prepared and their conductivity was evaluated. The effect of nitrile group ? CN/LiClO₄ mole ratio on the conductivity was investigated. The maximum conductivity of 1.21 × 10^?4 S cm^?1 (20°C) was achieved in the NBR/LiClO₄ composite at the ? CN/LiClO₄ mole ratio of 1/2.5, which was in accordance with the strongest coordination between ? CN and Li⁺ indicated by Fourier transform infrared spectrometry measurement. The conductivity was further increased by two to three times when 30 phr epoxy resin was introduced into NBR, and the conductivity could retain around the maximum value with the ? CN/LiClO₄ mole ratio ranged from 1/2.5 to 1/3.5, while the conductivity of NBR/LiClO₄ composite existed a decrease in the same range. Field emission scanning electron microscopy and atomic force microscopy characterization showed that epoxy resin significantly improved the dispersion of LiClO₄, leading to better surface smoothness of NBR/epoxy resin/LiClO₄ composite film and contributing to the increase of ionic conductivity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Mechanical properties and microstructure of acrylonitrile–butadiene rubber vulcanizates reinforced by in situ polymerized phenolic resin

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     

Mechanochemical preparation of devulcanized ground fluoroelastomers for the enhancement of the thermal stability of nitrile–butadiene rubber vulcanizates

Mechanochemically devulcanized ground fluoroelastomer (FKM) was used as a low‐cost functional additive for the enhancement of the thermal stability of nitrile–butadiene rubber (NBR) vulcanizates. Without the use of any chemicals, the stress‐induced mechanochemical devulcanization of ground FKM was achieved through solid‐state mechanochemical milling at ambient temperature. The sol fraction of the ground FKM was increased from its original 1.4 to 19.8% after milling; this confirmed the realization of the mechanochemical devulcanization of FKM. Moreover, the oxygen‐containing polar groups on the surface of the mechanochemically milled FKM benefitted its interfacial adhesion with the polar NBR matrix. The curing characteristics and mechanical properties of the devulcanized, FKM‐filled NBR vulcanizates were investigated and compared with those of the untreated FKM‐filled NBR vulcanizates. The results show that the mechanical properties of the devulcanized FKM‐filled NBR vulcanizates were much better than those of the untreated FKM‐filled NBR vulcanizates. The presence of the reclaimed FKM significantly increased the onset degradation temperature of the NBR vulcanizates as a result of the improved polymer–filler interaction, uniform dispersion, and high thermal stability of the reclaimed FKM. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

ZnBr2‐catalyzed chemical effects in poly(acrylonitrile‐ co‐butadiene)

The excellent chemical properties and resistance to oil of poly(acrylonitrile‐co‐butadiene), or nitrile–butadiene rubber (NBR), has led to the extensive use of these elastomers as O‐ring material in the oil extraction industry. The degradation of NBR gaskets is known to occur during the well completion and oil extraction process when they are exposed to bromide fluids such as ZnBr₂‐based completion fluid. Samples of NBR, polyacrylonitrile, and polybutadiene were exposed to ZnBr₂‐based completion fluid and analyzed by attenuated total reflectance (ATR) and diffuse reflectance IR. These analyses showed that the ZnBr₂ completion fluid promoted the hydrolysis of the nitrile group to form amides and carboxylic groups. The carbon–carbon double bonds in NBR were unaffected after short exposure to ZnBr₂‐based completion fluid but were quickly hydrated in acidic bromide mixtures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1250–1257, 2003     

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