乙烯含量对三元乙丙橡胶性能的影响

研究乙烯含量对三元乙丙橡胶(EPDM)性能的影响。结果表明:乙烯含量对EPMD胶料的门尼粘度和硫化特性无明显影响;随着乙烯含量的增大,EPDM硫化胶的硬度、拉伸强度、撕裂强度和回弹值总体呈增大趋势,低温性能变差。     

硫化体系对EPDM胶料老化性能和压缩永久变形的影响

使用硫黄硫化体系、过氧化物硫化体系以及二者并用硫化体系分别硫化了EPDM胶料,并进行了对比试验。结果表明,硫黄硫化胶物理机械性能较好;过氧化二异丙苯(DCP)硫化胶高温压缩永久变形较小;采用二者并用硫化体系并合理设计胶料配方,可使EPDM硫化胶具有较好物理机械性能和较小高温压缩永久变形;采用低硫高过氧化物用量,硫化效果较好。     

青岛科技大学开发出新型耐高低温丁腈橡胶

正青岛科技大学开发出一种耐高低温丁腈胶料,它是采用高丙烯腈含量的丁腈橡胶和乙丙橡胶共混制备耐高低温丁腈胶料,同时采用乙烯-醋酸乙烯酯橡胶、乙烯丙烯酸酯橡胶等作为NBR/EPDM共混胶的增容剂;加入甲基丙烯酸盐,在过氧化物硫化体系下与多种橡胶的交联形成互穿网络,从而改善共混胶的物理机械性能;加入碳     

动态硫化制备聚烯烃弹性体/三元乙丙橡胶/聚丙烯热塑性硫化胶的性能

讨论了三元乙丙橡胶、硫化剂(TX-29)及聚丙烯用量对聚烯烃弹性体/三元乙丙橡胶/聚丙烯热塑性硫化胶硫化特性和力学性能的影响。结果表明,随着三元乙丙橡胶生胶用量的增加,热塑性硫化胶的交联程度逐渐降低,胶料的拉伸强度、撕裂强度、定伸应力、硬度和高温压缩永久变形都呈减小趋势,而扯断伸长率和扯断永久变形变大。随着硫化剂用量的增加,胶料的拉伸强度、撕裂强度和定伸应力先增大后减小,高温压缩永久变形和扯断伸长率逐渐减小。随着聚丙烯用量的增加,胶料的流动性和力学性能改善,高温压缩永久变形呈现先增大后减小的趋势。     

复合促进剂在三元乙丙橡胶中的应用

研究了8种复合促进剂对三元乙丙橡胶(EPDM)的硫化特性、表观交联密度、力学性能、耐热空气老化性能、压缩永久变形和喷霜的影响，并与常用促进剂并用体系M／TT，DM／TT／BZ和M／TRA／BZ对比。结果表明，所用8种复合促进剂对EPDM硫黄硫化过程具有显著的促进作用。在相同用量下，含EG-3，EG-33，EG-35，EP-33，EM-33和NE-1胶料的硫化速度稍快于含EP-33(75％)和NE-2的胶料。含EG-3，EG-33和EM-33胶料的硫化程度相对较高。含各复合促进剂的硫化胶具有良好的力学性能，含EG-3，EG-33，EG-35和EM-33硫化胶的压缩永久变形值相对较低。含各复合促进剂的硫化胶在室温停放过程中(30d)均无喷霜现象。     

EPDM的压缩永久变形性能研究

研究了硫化体系、填充体系、增塑体系和硫化时间对EPDM高温下压缩永久变形的影响。实验结果表明：在硫黄、过氧化物、酚醛树脂3种硫化体系中,过氧化物配合助交联剂（TAIC）硫化的EP—DM压缩永久变形最小,硫磺硫化体系硫化胶则最大;胶料的压缩永久变形随着炭黑类填料用量的增加而降低,却随着无机类填料用量的增加而增加;填充具有高结构、适当粒径的炭黑（如N550）并适当延长硫化时间能有效降低EPDM的压缩永久变形。     

EPDM/NR并用胶压缩永久变形的研究

研究了EPDM/NR并用比、配合剂、硫化体系、补强体系和EPDM预硫化工艺等对EPDM/NR并用胶高温条件下压缩永久变形的影响。结果表明,当EPDM用量介于70~80份之间时,并用胶压缩永久变形最大;EGDMA配合剂改性的EPDM/NR并用胶压缩永久变形最小,聚异丁烯改性的最大;过氧化物硫化体系的EPDM/NR并用胶压缩永久变形最小,硫黄硫化体系的最大;随炭黑类填料用量的增加,并用胶压缩永久变形先减小后增大,但随着无机类填料用量的增加而增加;填充快压出炭黑（N550）并采用EPDM预硫化工艺能有效降低并用胶压缩永久变形。     

滑石粉/炭黑并用对丁腈橡胶性能的影响

研究滑石粉/炭黑并用量对丁腈橡胶(NBR)胶料性能的影响。结果表明,随着滑石粉用量的增大,NBR胶料的加工性能改善,交联程度下降,硫化胶的100%定伸应力、回弹值和压缩永久变形增大,拉伸强度和撕裂强度减小,耐热性能和耐非极性油性能提高,压缩模量增幅增大,弹性模量降低,Payne效应减弱,损耗因子减小。     

HNBR配合体系的研究

用硫黄、树脂、过氧化物分别制备了HNBR胶料,并比较了不同交联结构对性能的影响;评价了增塑剂TOTM,TP-95对提高胶料低温性能的效率及防RD,防4010NA,防MBZ,防Naugard445的防老作用.结果表明:采用过氧化物交联的胶料力学性能好.压缩永久变形低;增塑剂TOTM.TP-95都能有效降低Tg;防MBZ,防Naugard445对过氧化物交联体系的交联密度影响最小,硫化胶压缩永久变形低,对HNBR硫化胶有防老作用.     

耐低温超低压缩永久变形三元乙丙橡胶的配方设计

研究由乙烯、丁烯和亚乙基降冰片烯为单体,茂金属催化合成的新型三元乙丙橡胶（EBT EPDM）和通用三元乙丙橡胶（EPDM）的耐低温性能以及炭黑种类对EBT EPDM胶料耐低温性能的影响。结果表明：与EPDM胶料相比,EBT EPDM胶料的t₁₀和t₉₀均缩短,F_max－F_L增大;EBT EPDM硫化胶在低温条件（－40 ℃×72 h）下的压缩永久变形减小了71.5%,脆性温度降低了37.7%,低温回缩温度TR10最低,低温弯曲后表面未出现裂纹,耐低温性能优异;随着炭黑粒径的增大,EBT EPDM硫化胶的低温压缩永久变形减小,脆性温度降低;在相同低温条件下,EBT EPDM硫化胶的压缩永久变形与硅橡胶硫化胶相近,但EBT EPDM价格远低于硅橡胶,可拓宽其在低温密封领域的应用。     

Structure and properties of organoclay/EPDM nanocomposites: Influence of ethylene contents

Four organoclay (OC)/ethylene–propylene–diene rubber (EPDM) nanocomposites with different ethylene contents were prepared by melt blending. X‐ray diffraction spectrum (XRD) and transmission electronic microscope (TEM) photos showed that OC/EPDM nanocomposites were intercalated, and the ethylene content had little influence on the dispersion of OC. The addition of OC prolonged the optimum cure time and reduced the crosslink density of OC/EPDM. The improvement in tensile strength of OC/EPDM nanocomposites with high ethylene contents (67–70%) was larger than that of OC/EPDM nanocomposites with low ethylene contents (52–52.5%). XRD results of the stretched samples testified that the extension promoted orientation of silicate layers, and induced crystallization of polyethylene (PE) segments in OC/EPDM nanocomposites with high ethylene contents. The highly oriented micro‐fibrillar structure and more oriented amorphous chains, which resulted from strain‐induced crystallization of PE segments and the orientation of clay layers in OC/EPDM nanocomposites with high ethylene contents (67–70%), should be responsible for larger improvement in tensile strength than that of those nanocomposites with low ethylene contents (52–52.5%) © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 914–919, 2006     

不同牌号三元乙丙橡胶的结构与性能对比

对8个牌号三元乙丙橡胶(EPDM)的微观结构、硫化特性、物理机械性能、耐磨性能及耐老化性能进行了对比.结果表明,EPDM中第3单体亚乙烯基降冰片烯(ENB)质量分数影响了EPDM的硫化速率.8个牌号中EPDM 9950 C的硫化速率最快,EPDM 3722的硫化速率最慢;充油胶EPDM 3666的硫化速率与结构类似的E...     

乙烯含量对EPDM硫化特性和动态力学性能的影响

通过无转子硫化仪(MDR)、橡胶加工分析仪(RPA)及力学性能测试,研究了乙烯含量对过氧化物硫化EPDM未填充体系及炭黑填充体系硫化特性及动态力学性能的影响。结果表明,对于未填充/填充体系,随着乙烯含量的增加,胶料的交联程度提高,硫化反应表观速率常数K值增大,硫化诱导时间(td)不变。相比于未填充体系,加入炭黑,在促进体系硫化速率和硫化程度的同时,硫化后期还会加剧胶料的降解程度。乙烯含量高的EPDM,拉伸强度高,炭黑-橡胶相互作用大,炭黑补强效果好,但乙烯含量对EPDM橡胶储能模量的应变依赖性没有明显影响。     

Preparation and characterization of vinyltrimethoxysilane and dicumyl peroxide–cured (ethylene propylene diene monomer)/polypropylene thermoplastic vulcanizates

The present investigation deals with understanding the influence of vinyltrimethoxysilane (VTMS) concentration on the mechanical, thermal, thermomechanical, rheological, morphological, gel content, crosslinking density, and compression set properties of dynamically vulcanized ethylene propylene diene monomer (EPDM)/polypropylene (PP) (60/40, w/w) ‐based thermoplastic vulcanizates. It was determined that the values of crosslinking density, gel content, tensile strength, Young's modulus, elongation at break, and viscosity increased; whereas that of compression set, melting temperature, enthalpy of melting, crystallinity, and damping factor decreased with increased addition of VTMS in the EPDM/PP‐based thermoplastic vulcanizate. This is attributed to the physical crosslinking caused because of VTMS grafting on EPDM and chemical crosslinking induced by VTMS between PP and EPDM. This has been confirmed by Fourier‐transform infrared spectroscopy spectra, whereas the thermomechanical and scanning electron microscopy analysis confirmed increased compatibility between EPDM and PP on the addition of VTMS. J. VINYL ADDIT. TECHNOL., 23:312–320, 2017. © 2015 Society of Plastics Engineers     

Curing characteristics and kinetics of EPDM and EOC compounds in co-vulcanization as blend

Possibility of co-vulcanization of ethylene octene copolymer (EOC) and ethylene propylene diene terpolymer (EPDM) molecules was studied by assessing the curing characteristic and crosslinking kinetics of EOC and EPDM compounds. Regarding curing, the curing characteristics, cure rate index, and the torque difference (M_H − M_L) of the EPDM compound are quite similar to those of the EOC compounds at the curing temperature of 180 °C, especially when the EOC octene comonomer content is 5.9 or 9.7 mol %. The kinetic parameters E _a and k were analyzed. The study showed that EOC with 9.7 mol % octene comonomer content is very suitable for blending with EPDM, as it has crosslinking kinetics similar to the EPDM. This observation confirms the possibility of chemical co-crosslinking at EPDM–EOC interfaces, especially at the curing temperature of 180 °C. Differential scanning calorimetry and dynamic mechanical analysis were also used to assess interfacial crosslinking. The lowest activation energy of vulcanization is found for the EPDM/EOC blend with 9.7 mol % octene comonomer contents. Furthermore, chemical co-crosslinking in combination with chain flexibility in the EPDM/EOC blend with 9.7 mol % octene comonomer contents give lower tan δ at room temperature than for the blends with octene comonomer contents of 5.9 and 16.9 mol %. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47613.     

Evaluation of the aging of elastomeric acrylonitrile-butadiene rubber and ethylene-propylene-diene monomer gaskets used to seal plates heat exchanger

Acrylonitrile-butadiene rubber (NBR) and ethylene-propylene-diene monomer (EPDM) gaskets are used as seals in plates heat exchangers due to their elasticity and resilience. However, contact with fluids, oxygen, ozone, and heat lead to permanent deformation. This study investigates the degradation of gaskets submitted to similar service conditions: compressed in a groove for up to 360 h at 100 and 120°C. The analysis was carried through compression set (CS), compression stress relaxation, surface morphology, Shore A hardness, indentation modulus profile, crosslink density, and Fourier transform infrared region with attenuated total reflection analysis. For EPDM, in thermo-oxidative aging there is a counterbalance between chain scission and crosslinking, which increases CS while hardness and crosslink density remain low. For NBR, diffusion-limited oxidation causes heterogeneous oxidation, creating a crosslinking network near the surface. The values for CS, Shore A hardness, and crosslink density raised to 50%, 10%, and 75%, respectively. Furthermore, the side thermo-oxidation was reduced due to the presence of the groove, which reduces oxygen access. Using FITR analysis, a thermo-oxidative interaction mechanism was proposed for the EPDM and NBR gaskets. It was concluded that EPDM presented a more reliable behavior for the gasket and seal applications under the analyzed conditions.     

Facile Construction of Zn2+-Carboxyl Salt-Bonding as Sacrificial Unit in EPDM Rubber toward Mechanical and Sealing Resilience Performance Enhancement

In view of the facile reaction between carboxyl groups and zinc oxide (ZnO), Zn²⁺-carboxyl salt-bonding is constructed in ethylene propylene diene monomer (EPDM) rubber system by grafting reaction of glutamic acid (Glu), serving as sacrificial unit endowed EPDM-g-Glu/ZnO sample with excellent reprocessing and recycling ability. Through reaction of ZnO/methacrylic acid (MAA), EPDM-g-Glu/zinc dimethacrylate (ZDMA) composite is further prepared by in situ formation of ZDMA, and ZDMA is rapidly polymerized to form poly-ZDMA (PZDMA) containing massive Zn²⁺-carboxyl ion pairs once vulcanized, which exhibits fuzzy interface with the matrix. Relative to EPDM/ZDMA, the higher polymerization degree of ZDMA is achieved with the reduction of the size of PZDMA clusters, demonstrating the improvement of interfacial bonding, which results in the formation of a developed crosslinking network structure for EPDM-g-Glu/ZDMA. The mechanical strength, fracture toughness, and hysteresis loss of EPDM-g-Glu/ZDMA-40% show a significant increase in comparison with EPDM/CB-40% and EPDM/ZDMA-40%, meanwhile the relatively lower compression set and slower contact stress relaxation are achieved by energy dissipation mechanism of preferential rupture of Zn²⁺-carboxyl salt-bonding before breakage of covalent bonds during compression aging process, revealing the effective enhancement of durable sealing resilience performance.     

EPDM胶料的性能研究Ⅰ.炭黑补强EPDM胶料

研究了炭黑品种、用量和硅烷偶联剂Ｓｉ６９的使用等因素对炭黑补强ＥＰＤＭ胶料静态和动态性能的影响,并通过扫描电子显微镜分析了硫化胶的阿克隆磨耗表面,而且使用经改造的固特里奇压缩疲劳实验机测试了胶料内部的动态生热。研究结果表明：炭黑补强ＥＰＤＭ胶料生热较低,耐热老化性能较好,老化后动态性能有明显的改善;使用硅烷偶联剂Ｓｉ６９处理的炭黑,可显著降低胶料的动态生热;与ＳＢＲ载重轮胎胎面胶相比,ＥＰＤＭ胶料具有回弹性好、动态生热较小及老化后性能保持率较高的优点,可用于高温动态下使用的橡胶制品     

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。