EPDM/NR共混橡胶的性能研究

采用硫黄硫化体系和过氧化物(硫化剂DCP)硫化体系对EPDM/NR并用胶实施复合交联,考察了不同共混比EPDM/NR共混胶的硫化特性、硫化胶的物理机械性能、耐水性及耐溶剂性能。结果表明:复合交联后,胶料的硫化特性、物理机械性能均有所提高;EPDM母炼胶中DCP的用量要高于NR;胶料共混比为80/20(EPDM/NR),其耐水性和耐溶剂性能达到最佳。     

环氧化天然橡胶共交联改性EPDM/NR共混物的性能

将三元乙丙橡胶(EPDM)与环氧化天然橡胶(ENR)共交联改性后,再与天然橡胶(NR)共混,考察了ENR共交联改性EPDM/NR共混胶的硫化特性、硫化胶的物理机械性能、溶胀指数和耐热空气老化性能,并对该硫化胶进行了差示扫描量热分析。结果表明,EPDM经过ENR共交联改性后与NR共混,ENR共交联改性EPDM/NR共混胶的交联程度明显提高,各相达到了同步交联,硫化胶的综合性能得到了显著改善。     

NR／BR／EPDM共混胎侧胶中EPDM的结构：分子结构和炭黑分布对性能的影响

自EPDM问世以来,它在轮胎中的应用一直是一个难题。早在1960年,就认为这种橡胶可做为整体轮胎中SBR橡胶的耐臭氧的替代品。的确,曾用EPDM橡胶制成过完整的轮胎。但因其性能低劣,主要是耐磨耗、抗裂口增长和滚动阻力等性能不足,因而使EPDM从来没有在轮胎中得到应用。除此之外,缺乏自粘性也是轮胎生产中的一个主要问题,尽管通过选择合适的聚合物变量可以在很大程度上克服这一问题。     

NR／BR／SBR共混胶非轮胎制品胶料的性能

以天然橡胶、顺丁橡胶、丁苯橡胶共混物为基料，制造了普通三角带，夹布胶管，织物芯输送带以及聚酯三角带。实验结果表明，上述各制品胶料与ＮＲ／ＢＲ共混胶制品胶料相比，前者在焦烧性能、工艺性能以及化学纤维粘强度等方面均优于后者。     

天然橡胶／杜仲胶共混硫化胶性能研究

对杜仲胶与天然橡胶共混硫化胶的静态力学性能及动态伸张疲劳性能进行了研究。结果表明：在共混硫化胶体系中,杜仲胶质量分数在40%以下,能较好地保持其优良的力学性能;而杜仲胶对共混硫化胶动态伸张疲劳性能影响的大小在较高交联程度体系和较低交联程度体系中是不同的,通过差示扫描量热法（DSC）分析,初步解释了这一现象可能与杜仲胶存在的微晶作用有关。     

EPDM/酚醛树脂共混性能研究

在固体火箭发动机用烧蚀材料研究中，以三元乙丙橡胶(EPDM)为基体材料，以ZnO、TMTD、硫磺、白碳黑、酚醛等为配合剂，制备了EPDM橡胶基的烧蚀材料，采用酚醛作为增强剂，与EPDM进行共混，研究了酚醛的含量对材料性能的影响，测试了材料的物理机械性能和烧蚀性能。结果表明，当酚醛与EPDM的配比为75g时，可以使烧蚀材料形成稳定致密的炭化层，获得较低的烧蚀率，并且保持一定的机械性能。     

NR/EPDM并用橡胶研究

该文揭示了取得NR／EPDM并用胶共硫化性的关键：一是要选择合适的硫化促进剂，减小其在各橡胶相间的溶解度差：二是要平衡各胶种问的硫化活性，协调并用胶的硫化速率。此外还综述了NR／EPDM并用橡胶硫化体系以及硫化增容作用的研究概况。     

二氧化钛/天然橡胶纳米复合材料的制备及性能研究

采用乳液共混法将纳米二氧化钛(TiO_(2))与天然胶乳直接混合,制备TiO_(2)/天然橡胶(NR)纳米复合材料,研究自然凝固、乙酸凝固、氯化钙凝固3种凝固方式和TiO_(2)用量对TiO_(2)/NR纳米复合材料性能的影响。结果表明:乙酸凝固制得的NR及TiO_(2)/NR纳米复合材料的综合性能最优;TiO_(2)的加入可有效提高NR复合材料的物理性能和耐老化性能;随着TiO_(2)用量的增大,TiO_(2)/NR纳米复合材料的物理性能明显提高,耐老化性能有一定程度提升。     

天然橡胶/炭黑/二硫化钼复合材料的制备和性能研究

采用超声粉碎法制备二硫化钼(MoS_2)纳米碎片,以不同用量的MoS_2(纳米碎片)等量替代天然橡胶(NR)/炭黑(CB)复合材料中部分CB,制得NR/CB/MoS_2复合材料,研究不同用量MoS_2等量替代部分CB对复合材料Payne效应、硫化特性、物理性能、耐磨性能和动态力学性能的影响。结果表明:少量MoS_2等量代替部分CB有助于复合材料中填料分散,MoS_2用量过大则使填料又趋于聚集;少量MoS_2等量代替部分CB会减弱复合材料的Payne效应,有利于提高复合材料的物理性能和耐磨性能,但对复合材料的滚动阻力和抗湿滑性能影响较小;过量MoS_2等量代替部分CB,则其对复合材料的补强能力减弱,甚至导致复合材料性能下降。     

Formulation and curing characteristics of EPDM/NR and EPDM/SBR polyblends used in metallic surfaces rubber lining

In this work, a new elastomeric liner was introduced to protect the metal surfaces of storage tanks against corroding materials in petrochemical industries. This new liner was prepared on the basis of EPDM/NR and EPDM/SBR compounds. The elastomeric compounds were cured by using super‐heated water vapor at atmospheric pressure. To increase the rate of curing in these rubber samples, the optimum curing system contained 15 phr sulfur and 1.5 phr mercaptobenzothiazole, 1.5 phr zinc diethyl dithiocarbamate, and 1.8 phr tetramethylthiuram disulfide accelerators. Mechanical tests showed that ultimate tensile strength, elongation at break, and hardness of both polyblend samples were comparable to the SBR/NR blend, which is widely used in the rubber lining of metallic surfaces. In the next step, the chemical resistance of the samples was measured by placing them in a 30 wt % HCl solution. The tensile strength, elongation at break, and weight loss of the samples were measured before and after immersion in HCl. Also, the chemical resistances for EPDM/NR, EPDM/SBR, and SBR/NR samples were qualitatively measured in caustic solution. The cracking, blistering, permeability, and adhesion of the rubber samples to steel surface were observed. Finally, the results showed that EPDM/SBR (70/30) polyblend can be a suitable substitute for conventionally used SBR/NR (50/50) for a successful rubber used to line metallic surfaces. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Swelling behavior of NR/EPDM rubber blends under compression strain

The effect of different blend compositions of natural rubber (NR)/ethylene–propylene diene monomer rubber (EPDM) on the swelling behavior of that blend in motor oil under compression strain was investigated. The compression recovery of all blend ratios investigated had positive values at low applied compression values (3%). However, at high compression values (18 and 35%), the compression recovery had negative values. The lower weight uptake of motor oil was shown by the EPDM vulcanizate, whereas the 25/75 NR/EPDM blend showed the highest compression recovery. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3052–3057, 2001     

Effects of trans-polyoctylene rubber (TOR) on the properties of NR/EPDM blends

trans-Polyoctylene rubber (TOR) was melt blended with an incompatible NR/EPDM (70/30) blend. Mixing torque and temperature were reduced as TOR was added to NR/EPDM blend. The curing characteristics of the blend were affected as TOR participated in vulcanization and became a part of network. A scanning electron micrograph demonstrated that addition of TOR improved the compatibility of the blend and thereby led to a finer phase morphology. The ozone resistance of the blends was determined in terms of a critical stress–strain parameter. The critical stored energy density for ozone cracking was significantly enhanced for the TOR containing rubber blend. It was believed that the improvement in ozone resistance arised from finely dispersed ozone-resistant EPDM particles in the blend. TOR caused an improvement in dynamic properties and an increase in tensile modulus, but a decrease in tensile stress and elongation at break of the rubber blend. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 749–756, 1999     

Mechanical and sorption properties of poly(ethylene-co-vinyl acetate)(EVA) compatibilized acrylonitrile butadiene rubber/natural rubber blend systems

Poly (ethylene-co-vinyl acetate) (EVA) has been used as a compatibilizer for heterogeneous natural rubber/acrylonitrile butadiene rubber (NR/NBR) blends. NR/NBR (50/50) blends were compatibilized with varying amounts, from 0 to 10 parts per hundred rubber (phr), of EVA. The compatibility of the blend components in presence of EVA has been evaluated in terms of mechanical and sorption characteristics. The mechanical properties were found to be improved by the addition of EVA upto 6 phr. The solvent resistance of the compatibilized samples has been observed to be higher compared to the uncompatibilized blends; attributed to the increased interfacial adhesion between the blend components. DSC studies showed a shift of glass transition temperatures of the blend components towards higher temperatures indicating increased rigidity of the matrix in presence of EVA.     

Studies on the effect of 4A zeolite on the properties of intumescent flame-retardant agent filled natural rubber composites

This investigation focused on the research of 4A zeolite on the properties of intumescent flame retardant (IFR) agent filled natural rubber (NR) systems. The first part focused on the evaluation of such characteristics as cure characteristics, tensile property, abrasion loss, and cross-linking density of NR composites. Experimental results demonstrated that the addition of 4A zeolite could increase the cross-linking density of the NR systems. The incorporation of 0.3 phr of 4A zeolite with 50 phr of IF Ragent could improve the elongation value from 480 to 610%, probably 27% increase. Also, the abrasion loss was decreased from 0.95 to 0.70 cm³, nearly 26%. The second part focused on the study of flame-retardant (FR) properties of 4A zeolite filled NR systems. The properties and structure of these composites were characterized by limited oxygen index (LOI), thermogravimetric analysis (TGA), and cone calorimeter. It was proved that the addition of 0.3 phr of 4A zeolite into the IFR filled NR systems could lead to an increase of LOI value and thermal stability, together with a decrease of mass loss ration, rate of heat release (RHR), carbon monoxide (CO) evolution and carbon dioxide (CO₂) evolution, and so on, in a word, an improvement of FR properties.     

杜仲粗胶对NR共混性能的研究

本文通过采用生物酶预处理的方法对杜仲叶子进行处理,得到杜仲粗胶,研究了杜仲粗胶的用量对NR共混性能的影响。结果表明：杜仲粗胶的用量对于硫化胶的焦烧时间,工艺正硫化时间影响不大;用量超过15份后门尼粘度明显增加;随着杜仲粗胶用量的增加,硫化胶的物理机械性能提高,老化后整体的拉伸强度升高,扯断伸长率降低;硫化胶的弹性模量降低,损耗因子升高。     

三元乙丙橡胶硫化胶粉改性聚丙烯的研究

采用三元乙丙橡胶（EPDM）与EPDM硫化胶粉复合作为聚丙烯（PP）抗冲改性剂,研究了EPDM硫化胶粉和交联剂DCP用量对PP复合材料性能的影响。结果表明,PP复合材料的拉伸强度和弯曲强度随着硫化胶粉含量的增加而提高,冲击强度明显改善;而DCP用量增加对PP复合材料的拉伸强度和弯曲强度产生不利影响,少量DCP有助于提高PP复合材料的冲击强度;由DSC分析可知,硫化胶粉使PP熔体的结晶温度明显提高。     

Thermal stability of butyl/EPDM/neoprene based rubber compounds

Tyre curing bladders are usually prepared by using butyl/neoprene based compounds. To demonstrate the heat resistance and to extend the service life of a bladder, the mechanical properties of butyl/neoprene/ethylene–propylene–diene rubber (EPDM) based compounds in different compositions were analyzed and compared. In this study, the effects of partial replacements of IIR with different types of EPDM in different proportions were studied. Rheological and mechanical properties of vulcanizates were measured before and after the thermal ageing. Curing characteristics of unvulcanized compounds and mechanical properties, permanent set, fatigue index, and IRHD hardness of vulcanized compounds were measured. The better results were obtained by using the recipes containing Keltan 27 type EPDM of 10–20 phr. Mechanical properties of recipes decreased due to high EPDM ratio in the recipes studied. The service life of tyre curing bladders can be increased by the replacement of EPDM with butyl rubber in appropriate type and quantity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 557–563, 2007