TCY／硫黄对ACM／NBR并用胶的交联作用

从混炼胶的硫化特性和硫化胶物理性能等方面考察了三聚硫氰酸（ＴＣＹ）、硫黄和ＴＣＹ／硫黄对丙烯酸酯橡胶（ＡＣＭ）、丁腈橡胶（ＮＢＲ）及其并用胶的交联作用。结果表明,ＴＣＹ／硫黄硫化体系适用于ＡＣＭ／ＮＢＲ并用胶、并用胶的物理性能达到甚至超过了两种胶料的物理性能的加和水平;ＡＣＭ／ＮＢＲ共混并用,加工性能得到明显改善     

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。     

Naturally occurring amino acid: Novel curatives for chloroprene rubber

Polychloroprene is a diene rubber, but unlike other diene rubbers, its compounding with various additives and curing mechanisms is different. A derivative of thiourea, ethylene thiourea (ETU), is widely used to vulcanize chloroprene rubber (CR), and the vulcanizates thus obtained exhibit excellent mechanical properties, good aging resistance, and very good sealing properties. However, the problem is that ETU is reported to be a potent carcinogenic compound, and hence, the effective substitution for ETU has been extensively explored. In this study, we used a naturally occurring amino acid derivative, dimethyl L ‐cystine, as an ecofriendly compound for the vulcanization of CR. It had a significant influence on the curing characteristics and mechanical properties, such as modulus, tensile strength, elongation at break, and hardness values. The concentration of this novel crosslinking agent and also the curing temperature were optimized. In the presence of dimethyl L ‐cystine, the amount and activity of magnesium oxide also exhibited significant influences on the crosslinking characteristics. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3981–3986, 2006     

不同硫化体系对环保型硬丁腈橡胶性能的影响

以松香酸皂与油酸皂组成的复合乳化体系制备的中试产品丁腈橡胶(NBR)为基胶,分别用硫黄体系和过氧化物体系进行硫化,研究了NBR混炼胶的硫化特性和硫化胶的物理机械性能、耐老化性能、耐油及耐寒性能,并与传统产品NBR 3604进行了比较。结果表明,采用硫黄体系时,NBR混炼胶的硫化程度较浅,硫化速率较慢;采用过氧化物体系时,NBR混炼胶的硫化程度较深,硫化速率较快,NBR胶料宜采用过氧化物硫化体系进行硫化;2种硫化体系下制得NBR硫化胶的物理机械性能与NBR3604硫化胶相差不大,过氧化物硫化体系制得NBR硫化胶的耐老化性能较好;与NBR 3604硫化胶相比,2种硫化体系下制得NBR硫化胶的耐寒性稍好,耐油性稍差。     

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     

官能化高乙烯基聚丁二烯橡胶与丁腈橡胶共混胶的性能

以氢化钠为活性剂、马来酸酐为改性剂,通过负离子反应对高乙烯基聚丁二烯橡胶(HVBR)进行官能化改性制备了官能化HVBR(FHVBR)。考察了FHVBR与丁腈橡胶(NBR)共混的质量比对FHVBR/NBR共混胶硫化特性、力学性能、耐热氧老化性能和电性能的影响,并通过差示扫描量热仪和扫描电子显微镜探讨了共混胶的两相相容性。结果表明,随着NBR用量的增加,FHVBR/NBR共混胶的硫化时间缩短、硫化效率提高,定伸应力和硬度增大,耐老化性能得以改善。NBR用量的增加使得FHVBR/NBR共混胶对不同频率下的微波吸收能力增强,共混胶的电阻率下降,导电性增强。然而,NBR用量增加导致共混胶的拉伸强度略有下降。     

Modification of a nitrile-phenolic bonding agent by addition of an interfacial agent: effect on the practical adhesion between nitrile rubber and metal

—The mechanism of vulcanization bonding of a nitrile rubber (NBR) elastomer to metal with a single-coat nitrile-phenolic bonding agent is discussed. A nitrile-phenolic bonding agent consisting of NBR, phenol formaldehyde (PF) resin, and vulcanizing agents was modified with an interfacial agent (p-cresol formaldehyde resin) and the effect of interfacial agent addition on the practical adhesion between metal and the NBR elastomer after vulcanization was investigated. The adhesion strength was measured in terms of the metal-to-NBR elastomer peel strength using the bonding agent. The addition of p-cresol formaldehyde (PCF) resin to the bonding agent with a proportionate reduction of PF resin initially improved the peel strength; a maximum was reached at about 20% PCF content and then decreased with a further increase in the PCF content. The improvement in peel strength produced by the addition of PCF resin is attributed to the increased chemical bonding between NBR and the phenolic resin. The drop in peel strength above 20% PCF content is explained by the increased diffusion of the bonding agent into the NBR elastomer, away from the bond line, leading to a starved glue line. The mechanism for the optimum performance at about 20% PCF resin content is believed to be due to the balance of diffusion and chemical crosslinking.     

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     

Aluminum powder filled nitrile rubber composites

Effect of aluminum powder on the properties of nitrile rubber (NBR) composites and the role of bonding agent viz. hexamethylene tetramine‐resorcinol has been investigated. Shore A hardness of the aluminum powder filled composites is lower than that of high abrasion furnace (HAF) and acetylene black (ACB) filled nitrile rubber composites and can be increased by the addition of bonding agent. Equilibrium swelling decreased considerably by the use of hexamethylene tetramine‐resorcinol, suggesting an improved nitrile rubber–aluminum powder adhesion. A marked increase in thermal conductivity is obtained with the incorporation of aluminum powder. Increased thermal conductivity reduced the additional time needed for the vulcanization of thick rubber articles and imparted uniform curing throughout the material. In nitrile rubber, the modulus and tensile strength followed the order HAF > ACB > aluminum powder. Combination of HAF and aluminum powder in NBR gave composites with good thermal conductivity and mechanical properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3156–3161, 2004     

Synergistic Effect of Copper Sulfate and Tetramethylthiuram Monosulfide Induced Metal-Coordination Cross-Linking in Nitrile–Butadiene Rubber

The cross-linking microstructure formed by the metal-coordination bonds provides excellent properties for rubber materials. Copper sulfate (CuSO₄) and tetramethylthiuram monosulfide (TMTM) are successfully compounded with nitrile–butadiene rubber (NBR) to fabricate vulcanizates by the coordination cross-linking. The curing characteristics, mobility of macromolecular segment, mechanical properties, morphology analysis, swelling properties, and dynamic features under cyclic compression of the vulcanizates are investigated systematically. The results indicate that the microstructure of 3D cross-linking is held together by the metal-coordination bonds between Cu²⁺ and  CN. The torque during static vulcanization, tensile strength, and cross-linking density of the obtained NBR/CuSO₄/TMTM vulcanizates are better than that of NBR/CuSO₄ vulcanizates, which is attributed to the synergistic effect between the radicals formed by the splitting of TMTM under thermal activation and the Cu²⁺; moreover, the highly reactive [Cu(S_nCNMe₂)]^•2+ complexes are formed by the synergistic effect and promote the coordination stability of NBR and CuSO₄ effectively. The excellent tensile properties of the prepared NBR/CuSO₄/TMTM vulcanizates via synergistic effect made the metal-coordination cross-linking attractive in the field of industrial application.     

共混橡胶的共硫化研究

探讨了多种共混橡胶的共硫化体系及其对共混橡胶性能的影响。其中采用共硫化剂硫化CO/ECO、CSM/NBR、IIR/EPDM、IIR/CIIR共混胶,采用复合硫化剂硫化PUR/CR、ACM/ECO、ACM/NBR、CR/CIIR、CR/SBR共混胶,研究了硫化体系品种和用量对几种共混胶的硫化特性和力学性能的影响,为共混橡胶的硫化提供研究方案和理论指导。     

Effect of adhesive‐coated glass fiber in natural rubber (NR), acrylonitrile rubber (NBR), and ethylene–propylene–diene rubber (EPDM) formulations. II. Effect of cyclic loading,abrasion, and accelerated aging

Treated glass fibers (RICS, 3 and 6 mm in length) were added at a concentrations of 10, 20, and 30 phr in natural rubber (NR), nitrile rubber (NBR), and ethylene–propylene–diene comonomer (EPDM) formulations, in both plain and carbon black mixes. The compounds were mixed in two‐roll mill and were evaluated for their resistance to hot‐air aging, abrasion, compression set, Goodrich heat buildup, De Mattia fatigue, and for NR mixes, adhesion in the tensile mode. The vulcanizates of the three rubbers showed resistance to hot‐air aging. Abrasion resistance was poor for NR, and it improved with carbon black addition in the presence of treated glass fiber in NBR. In carbon‐black‐added EPDM vulcanizates, the abrasion resistance and fatigue resistance were better. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1124–1135, 2004     

天然橡胶硫化动力学研究

采用硫化仪测定了2种不同凝固工艺的天然橡胶（NR）的硫化过程,探讨了制胶工艺、配方和温度对硫化动力学参数的影响。研究结果发现,随着温度的上升,硫化速率常数迅速上升。在纯胶体系中,微生物凝固胶的活化能高于酸凝固胶。当加入炭黑后,酸凝固胶的活化能升高,而微生物凝固胶的活化能下降。     

双金属稀土促进剂对丁苯橡胶/天然橡胶胎面胶的影响

通过配位反应制备得到双金属硫化促进剂二乙基二硫代氨基甲酸锌镧配合物(ZnLaDC),在不添加传统活化体系氧化锌(ZnO)/硬脂酸(SA)的情况下,考察了ZnLaDC用量对丁苯橡胶(SBR)/天然橡胶(NR)胎面胶复合材料硫化特性及物理机械性能的影响,并与传统硫化体系二乙基二硫代氨基甲酸锌(ZnDC)/ZnO/SA制备的硫化胶性能进行了对比。结果表明,随着ZnLaDC用量的增加,SBR/NR胎面胶复合材料的硫化特性、压缩疲劳生热性能及耐磨性得到有效提高,当ZnLaDC用量为5份时,复合材料的综合性能最佳。与传统硫化体系ZnDC/ZnO/SA制备的硫化胶相比,采用ZnLaDC制备的硫化胶具有更优异的静态力学性能及耐切割性。     

Adhesion of polyvinyl alcohol cord,and fabric to special purpose rubbers in the presence of HRH dry-bonding agents

The adhesion of polyvinyl alcohol (PVOH) cord and fabric to different special purpose rubbers has been studied with a view to making use of the textile in various applications such as in gaskets, diaphragms, and other industrial molded goods. Adhesion was measured with both raw and chemically treated cords and fabrics, and in the presence of hydrated silica-resorcinol-hexamethylenetetramine (HRH) dry-bonding agents. The pull adhesion strength of the PVOH cable cord (untreated) to EPDM rubber and polyurethane rubber improved significantly on incorporating HRH dry-bonding agents. However, for chemically treated cords the bond strength improved for EPDM rubber but decreased marginally for polyurethane rubber. The peel adhesion strength of the PVOH fabric (both raw and chemically treated) improved slightly with the introduction of dry-bonding agents for all the rubbers studied except nitrile rubber. The physicomechanical properties and aging characteristics of the rubber vulcanizates in the presence of the dry-bonding agents are reported.     

有效硫化体系下对MPU/NBR共混胶性能的研究

探究了在有效硫化体系下,聚醚型混炼型聚氨酯橡胶(MPU)与丁腈橡胶(NBR)并用比对共混胶性能的影响。研究表明,NBR的加入使得共混胶硫化速度变快,随着NBR份数的增加,拉断强度和扯断伸长率不断下降,表观交联密度先减小后增大,不同伸长率下的定伸应力呈现不同的变化规律。共混胶耐热空气老化性能和耐热油老化性能优异,在80℃高温拉伸中,MPU的拉断强度折损率要高于NBR。在动态力学性能研究中发现,20份NBR的加入使得共混胶动态生热明显增大。     

动态硫化丁腈橡胶/尼龙6热塑性弹性体的制备及性能

采用动态硫化法制备了丁腈橡胶/尼龙6热塑性弹性体(NBR/PA 6 TPV),考察了硫化体系、羧基丁腈橡胶(XNBR)以及增塑剂高密度氧化聚乙烯蜡(AC-316 A)和正丁基苯磺酰胺(BBSA)对TPV硫化特性、力学性能和微观形貌的影响。结果表明,以促进剂HVA-2/促进剂DM为硫化体系,动态硫化过程体系黏度的变化比以酚醛树脂/SnCl2为硫化体系时更平稳;但用后者制备TPV,其撕裂强度和扯断伸长率等力学性能更优,PA 6的结晶度更低。XNBR能对NBR和PA 6起到增容作用,当XNBR与NBR的质量比为10/90时,TPV的力学性能最好,NBR在PA 6中分散得最均匀。AC-316 A和BBSA都能对TPV起到增塑作用,随其用量的增加,体系黏度降低。     

Novel method for preparation of carboxylated nitrile rubber–natural rubber blends using bis(diisopropyl)thiophosphoryl polysulfides

Bis(diisopropyl)thiophosphoryl trisulfide (DIPTRI) and bis(diisopropyl)thiophosphoryl tetrasulfide (DIPTET) are successfully used as a novel coupling agent and accelerator, respectively, to covulcanize an elastomer blend comprising polar carboxylated nitrile rubber (XNBR) and nonpolar natural rubber (NR). These compounds are capable of forming a chemical link between these dissimilar rubbers to produce a technologically compatible blend as judged by a swelling experiment. The blend vulcanizates thus produced exhibit enhanced physical properties that can further be improved by adopting the two‐stage vulcanization technique and also by judicious selection of the NR:XNBR ratio. The blend morphology assessed by scanning electron microcroscopy micrographs accounts for significant improvement in the physical properties of the blend vulcanizates, particularly in two‐stage vulcanization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1725–1736, 2001     

Preparation and characterization of acrylonitrile–styrene–methylmethacrylate terpolymer as a compatibilizer for rubber blends

Acrylonitrile‐co‐styrene‐co‐methylmethacrylate (AN‐S‐MMA) terpolymer was prepared by bulk and emulsifier‐free emulsion polymerization techniques. The bulk and emulsion terpolymers were characterized by means of Fourierr transform infrared spectroscopy, ¹³C nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography, thermal gravimetric analysis, and elemental analysis. The kinetics of the terpolymerization were studied. The terpolymers were then incorporated into butadiene—acrylonitrile rubber (NBR)/ethylene propylene diene monomer rubber (EPDM) blends and into chloroprene rubber (CR)/EPDM blend. The terpolymers were then tested for potential as compatibilizers by using scanning electron microscopy and differential scanning calorimetry. The terpolymers improved the compatibility of CR/EPDM and NBR/EPDM blends. The physicomechanical properties of CR/EPDM and NBR/EPDM blend vulcanizates revealed that the incorporation of terpolymers was advantageous, since they resulted in blend vulcanizates with higher 100% moduli and with more thermally stable mechanical properties than the individual rubbers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3143–3153, 2003     

On the role of sulfurization in adhesion of nitrile rubber to brass

The effects of conditions — in which nitrile rubber was vulcanized in contact with metallic substrates (e.g. brass or steel) — on the adhesion strength of rubber-substrate joints were investigated. The adhesion strength was estimated by measuring the peel resistance when the metallic foil was separated from the vulcanizate film. When the raw rubber was vulcanized, the plots of 'adhesion strength-versus-vulcanization parameters' (such as temperature and length of the process) show maxima, the pattern (character) of which depends on the substrate material. For joints with steel, the maximum in adhesion strength results from variations in the mechanical properties of the rubber which undergoes transition from the viscous flow to the highly elastic relaxation state in the course of vulcanization. The authors believe that the strength of adhesional bonding in rubber/brass systems depends on the mechanical properties of the sulfide film formed on the substrate in the course of vulcanization of the rubber. Experimental results which support the cohesive nature of the failure in the sulfide film in rubber/brass joints are presented in this paper.