硅酸盐纳米短纤维增强三元乙丙橡胶复合材料的结构与性能

用硅烷偶联剂改性针状硅酸盐(FS)与三元乙丙橡胶(EPDM)机械共混,制备了EPDM/改性FS复合材料,研究了FS在EPDM中的分散性,考察了偶联剂和改性FS用量、FS所含自由水对复合材料力学性能和各向异性的影响.结果表明,经过偶联荆改性的FS能够解离成纳米纤维均匀分散于EPDM中,每100份FS的偶联刺最佳用量为24份;EPDM/改性FS复舍材料具有短纤维增强橡胶复合材料的应力-应变特征和力学性能的各向异性,且随改性FS和偶联剂的用量增加,这种力学行为更加明显;FS中所舍自由水对复合材料的常温和高温拉伸性能有明显影响.     

用于变压器的丁腈橡胶/三元乙丙橡胶并用胶

为了实现丁腈橡胶(NBR)与三元乙丙橡胶(EPDM)并用作为变压器密封材料,研究了并用比、增容剂及硫化体系种类对NBR/EPDM并用胶的影响。结果表明,NBR/EPDM(质量比)为70/30时并用胶具有良好的耐臭氧性能与最佳的综合物理机械性能;在并用胶中加入增容剂乙华平8784可以改善其物理机械性能;使用过氧化物硫化体系硫化并用胶的物理机械性能比使用硫黄/促进剂硫化体系者更好。     

碳化硅改性三元乙丙橡胶复合材料的非线性电阻特性

采用纳米碳化硅(SiC)或SiC晶须改性的三元乙丙橡胶制备复合材料,研究了SiC用量对复合材料体积电阻率的影响,分析了非线性电阻产生的机理。结果表明,在低场强区(电场强度小于10 kV/mm),复合材料的电阻率随着SiC用量的增加缓慢下降;在高场强区(大于20 kV/mm),复合材料的电阻率随着SiC用量的增加快速下降;SiC用量增大时,SiC粒子间的距离减小,非线性效果增强;采用大长径比的SiC晶须作为改性材料可以降低非线性电阻的临界电场强度。     

Mechanical and thermal properties of gamma irradiated ethylene propylene diene monomer rubber/vermiculite clay/maleic anhydride composites

Vermiculite clay (VMT) was first treated with 2 M of hydrochloric acid. The VMT, before and after acid‐treatment, was characterized by X‐ray diffraction (XRD) and transmission electron microscopy. The untreated (VMT) and acid‐treated vermiculite clay DVMT) at different contents (2.5–10 phr) and maleic anhydride (MA) at different contents (3–10 phr) were mixed with ethylene polyethylene diene rubber (EPDM) via direct melt compounding in an internal mixer. The mechanical and thermal properties of gamma irradiated composites were studied. The results indicated that the physical properties of gamma irradiated EPDM/DVMT/MA nanocomposites were greatly improved after loading with either DVMT or MA. The improvement was achieved when the content of DVMT clay was 5 phr, MA 7 phr and irradiation dose at 75 kGy. J. VINYL ADDIT. TECHNOL., 25:E3–E11, 2019. © 2018 Society of Plastics Engineers     

Development of hydroxyapatite nanoparticles reinforced chlorinated acrylonitrile butadiene rubber/chlorinated ethylene propylene diene monomer rubber blends

Hydroxyapatite nanoparticles (HA) reinforced polymer blend based on chlorinated nitrile rubber (Cl-NBR) and chlorinated ethylene propylene diene monomer rubber (Cl-EPDM) were prepared. Resulting blend composites were analyzed with regard to their rheometric processing, crystallinity, glass transition temperature (T_g), mechanical properties, oil resistance, AC conductivity, and transport behavior. The decrease in optimum cure time with the addition of HA is more advantageous for the development of products from these blend nanocomposites. The XRD, FTIR, and SEM confirmed the attachment and uniform dispersion of HA nanoparticles in the Cl-NBR/Cl-EPDM blend. The good compatibility between polymer blend and nanoparticles was also deduced by the formation of spherically shaped HA particles in the blend matrix determined by TEM analysis. DSC analysis showed an increase in T_g of the blend with the filler loading. The addition of HA particles to the blend produced a remarkable increase in tensile and tear strength, hardness, AC conductivity, abrasion, and oil resistance. The diffusion of blend composites was decreased with an increase in penetrant size. The diffusion mechanism was found to follow an anomalous trend. Among the blend composites, the sample with 7 phr of HA not only showed good oil and solvent resistance but also a remarkable increase in AC conductivity and mechanical properties.     

Thermal aging of bentonite‐filled ethylene propylene diene monomer composites

Bentonite‐filled ethylene propylene diene monomer (EPDM/Bt) composites were prepared using two roll mill compounding method and the effect of Bt loading on the thermal aging, swelling resistance and crosslink density of EPDM/Bt composites were studied. The effect of in situ addition of different silane coupling agents (SCAs) on the above properties at optimum Bt loading of EPDM/Bt composite was also investigated. Thermal aging test results show that the tensile strength and tensile modulus at 100% elongation (M100) increase initially for 2 days aged composites and decrease slightly after 4 days of aging, meanwhile the elongation at break (E_b) decrease gradually with aging period as compared to the unaged composites. Upon aging, swelling resistance increase initially indicating increased crosslink density of EPDM/Bt composite due to post‐curing and reduced after 4 days of aging due to crosslink destruction and EPDM chain scissioning. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4419–4427, 2013     

交替层状结构氯化丁基橡胶/三元乙丙橡胶复合材料的阻尼性能

采用多层共挤技术制备了具有交替层状结构的氯化丁基橡胶(CIIR)/三元乙丙橡胶(EPDM)复合材料,并与常规共混法cIIR/EPDM复合材料的阻尼性能进行了比较.结果表明,交替层状复合材料具有双连续相结构;与共混复合材料相比,交替层状结构复合材料的损耗因子和有效阻尼范围增大,且随着其层数的增加,损耗因子和有效阻尼范围、储能模量和损耗模量均增大;室温下层数较多的CIIR/EPDM复合材料在100～110 Hz的阻尼性能更优异.     

Studies on electrically conductive composites of ethylene propylene diene monomer rubber and steel fibers

Electrically conductive composites comprised of ethylene propylene diene monomer (EPDM) rubber and steel fibers were prepared by an open mill mixing method. Fibers of two distinctly different lengths (5 mm and several meters) were used and the influence of these fibers on electrical conductivity, mechanical, thermal, and physical properties of the composites was investigated. Composites with different compositions were prepared by varying the loading levels of fibers from 20–100 phr (parts per hundred parts of rubber). Homogeneity of the composites was determined using scanning electron microscopy. Further analysis included the measurement of resistance, hardness, tensile strength, tear strength, rebound resilience, etc. The results of the analysis revealed that the addition of steel fibers rendered conductivity to the otherwise insulating EPDM rubber even at small loading levels, however, the length appears to have negligible effect on conductivity. In case of short fibers, the resistance of composites was observed to decrease from > 40 MΩ (Initial value of EPDM rubber) to 25 KΩ at a loading level of 20 phr with a further significant decrease of the order of 10³, that is around 18 Ω at 100 phr. Composites with long fibers exhibited resistance in the range of 15 kΩ–70 Ω at loading levels between 30 and 100 phr. The conductivity of the sample is observed to be altered negligibly on ageing. Mechanical properties such as hardness, tensile, and tear strength were observed to be enhanced in case of composites except resilience which decreased by 29 % in comparison to EPDM rubber. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Investigation of novel polyanilines as new antioxidants for ethylene propylene diene monomer rubber composites

Oxidative aging is a significant deterioration process that affects the performance and durability of rubber materials in various applications. Therefore, this study focuses on the development of new antioxidants-based on polyaniline for ethylene propylene diene monomer (EPDM) rubber to enhance its resistance to oxidative aging. The novel polyanilines were prepared using in situ polymerization method and characterized using Fourier transforms infrared (FTIR) and thermogravimetric analysis (TGA). FTIR illustrates the success synthesis of polyanilines as it shows their characteristic functional groups. The thermal stability of the formed polyanilines is discussed through TGA and derivative of thermogravimetry (DTG) curves. The curves prove the good thermal stability of the synthesized polymers. The prepared polyaniline compounds were mixed to carbon black filled-EPDM rubber composites using a roll mill and then vulcanized using sulfur curing process. Accelerated aging tests for the prepared EPDM rubber composites were conducted to evaluate the effectiveness of the antioxidants. Moreover, their impact on rheometer, mechanical, and swelling properties was studied. The results showed that the EPDM samples with the prepared polyaniline compounds exhibited improved oxidative properties compared to the EPDM sample with commercial antioxidant 2,2,4-trimethyl-1,2-dihydroquinoline. These findings suggest that the novel antioxidants have the potential to enhance the durability and performance of EPDM rubber in various applications.     

超细全硫化粉末丁苯橡胶/三元乙丙橡胶共混物的结构与性能

制备了超细全硫化粉末丁苯橡胶(UFPSBR)/三元乙丙橡胶(EPDM)共混物,研究了其硫化特性、相态结构、动态力学性能及物理机械性能。透射电镜观察表明,无论UFPSBR与EPDM共混比如何,UFPSBR粒子始终保持为分散相。当UFPSBR用量为10份(质量)时,它在EPDM中的分散相尺寸为200 nm左右;用量较高时其分散相尺寸较大,存在大量的聚集体。动态力学分析结果显示共混物存在2个玻璃化转变温度,说明共混物存在两相结构。加工性能分析结果表明,UFPSBR粒子在EPDM基质中形成了网络结构,对EPDM基质起到了较好的增强作用,当UFPSBR与EPDM的质量共混比为50/50时,共混物的拉伸强度可达13.4 MPa。UFPSBR对EPDM的硫化特性有明显影响。     

Comprehensively improved mechanical properties of silane crosslinked polypropylene/ethylene propylene diene monomer elastomer blends

The properties and structure of silane crosslinked polypropylene (PP)/ethylene propylene diene monomer (EPDM) elastomer blends had been carried out. Fourier transform infrared spectroscopy and gel content tests were employed to evaluate the crosslinking reaction of PP/EPDM blends. Crosslinking efficiency of PP/EPDM blends was investigated using thermogravimetric analysis, differential scanning calorimeter, dynamic mechanical analysis, dynamic rheology, and tensile testing. Tanδ curves of silane crosslinked PP/EPDM blends exhibited an obvious “gel point” originated from the formation of dynamic crosslinking network. The blend corresponding to the “gel point” presented comprehensively improved mechanical properties. These results demonstrated that characteristic rheological parameters showed close correlations with key mechanical properties of silane crosslinked PP/EPDM blends. Scanning electron microscopy images illustrated that crosslinking had remarkably changed the morphologies of PP/EPDM blends. The large deformation mechanism of these blends had been suggested.     

Glass fibers reinforced poly(ethylene 2,6‐naphthalate)/ethylene propylene diene monomer composites: Structure,mechanical, and thermal properties

Ethylene propylene diene monomer (EPDM) was blended with glass fibers (GFs)‐filled poly(ethylene 2,6‐naphthalate) (PEN) composites to improve the impact properties of PEN. The impact strength of PEN/EPDM/GF composite (PEN/EPDM = 60/40) was about 62 J/m, which was nearly four times higher than the PEN/GF composite without EPDM. At the same time, the tensile strength and flexural modulus were still maintained at considerable values since the GFs compensated the loss of mechanical properties of PEN by incorporation of EPDM. The scanning electron microscopy results showed that the GFs were orientated and homogenously dispersed in the PEN matrix and, after incorporation of EPDM, the surface of GFs were covered by a matrix layer which became coarse and thick with increasing EPDM content. The dynamic mechanical analysis results showed the poor compatibility between PEN and EPDM. The thermal gravimetric analysis revealed that the PEN matrix protected the dispersed EPDM domains, resulting in an increased maximum peak temperature (T_max) of the EPDM phase. At last, the results of differential scanning calorimetry analysis indicated that incorporation of EPDM led to an increase in crystallization rate and improvement in crystallization temperature. POLYM. COMPOS., 35:939–947, 2014. © 2013 Society of Plastics Engineers     

Thermal and mechanical properties of silicon rubber/cis‐polybutadiene rubber/ethylene–propylene–diene monomer blends

Considering the properties of silicon rubber, ethylene–propylene–diene monomer (EPDM), and cis‐polybutadiene rubber (BR), a blend made by a new method was proposed in this article; this blend had thermal resistance and good mechanical properties. The morphology of the blend was studied by SEM, and it was found that the adhesion between the phases of BR, EPDM, and polysiloxanes (silicon rubber) could be enhanced, and the compatibility and covulcanization were good. The influence of the mass ratio of peroxide and silica on the mechanical properties and thermal resistance of the blend was studied. The results showed that the mechanical properties and thermal resistance of the blend were improved when silicon rubber/BR/EPDM was 20/30/50, dicumyl peroxide/sulfur was 2.5/2.5, and the amount of silica was 80 phr. The integral properties of rubber blend had more advantages than did the three rubbers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4462–4467, 2006     

Dye sorption characters of gamma irradiated foamed ethylene propylene diene monomer (EPDM) rubber/clay composites

Composites based on gamma irradiated ethylene propylene diene monomer rubber in foam structure, loaded with different types of clays were used as adsorbents for different classes of dyestuffs (basic, acid, reactive and disperse) from aqueous solutions. The clays under investigation were Aswan clay (ASC) and sodium montmorillonite (Na-MMT). The effect of adsorbent composition, irradiation dose, pH and contact time on dye sorption was studied. It was found that the rubber composites loaded by Na-MMT gave maximum adsorption of the basic dye (～42%) in aqueous solution, while the rubber composites loaded by AS clay gave maximum adsorption (～28%) of the acidic dye. On the other hand, both type of clays did not show no affinity toward reactive and disperse dyes. The efficiency of dye removal was found to increase with increasing the pH and contact time. It was also observed that the irradiation dose (50 kGy) was the optimum dose for the removal of dyes for all rubber composites.     

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。     

Tensile,thermal, flammability and morphological properties of sepiolite filled ethylene propylene diene monomer (EDPM) rubber composites

The effect of sepiolite loading content on the curing characteristics, tensile mechanical, thermal, swelling, flammability and morphological properties of sepiolite-filled ethylene propylene diene monomer (EPDM) composites was investigated. The composites were prepared with sepiolite loadings of 0–70 part per hundred (phr) of rubber using a two-roll mill. The results highlighted the improvement in the tensile properties and cross-link density values peaked at 60 phr of sepiolite loading. The scorch time, curing time, swelling percentage, and linear burning rate of the composites decreased with an increase in sepiolite loading. Thermogravimetric analysis showed an increasing trend with increase in sepiolite loading. The temperatures corresponding to 5, 25 and 50% weight loss (T_5wt%, T_25wt% and T_50wt%) and the percentage of char residue gradually increased with increase in sepiolite loading. The homogenous dispersion of the sepiolite particles in the EPDM matrix and the formation of zigzag structures, especially at 60 phr, were the main reasons of the improvement of mechanical properties which were confirmed by the morphological studies. The formation of a protective layer, which acted as a barrier against heat transfer into the deeper layers, enhanced the flammability resistance of the composites. Notably, the EPDM filled with 60 phr sepiolite exhibited excellent performance in the aspects of mechanical, thermal stability and flammability properties and resistance towards swelling.     

Effects of peroxide and gamma radiation on properties of devulcanized rubber/polypropylene/ethylene propylene diene monomer formulation

Mechanical and thermal properties of devulcanized rubber (DR)/polypropylene (PP)/ethylene propylene diene monomer blends (EPDM) were studied at various concentrations of dicumyl peroxide (DCP) and gamma radiation doses. The blends showed improved mechanical properties for vulcanized sample. The coupling of DR/PP/EPDM with different proportions of DCP was investigated by X‐ray diffraction and scanning electron microscopy techniques. Evaluation of the developed blends, unirradiated and gamma irradiated, was carried out using elastic modulus, tensile strength, elongation at break, thermogravimetric analysis, kinetic analysis, and DSC measurements. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40611.     

过氧化物体系中天然橡胶/三元乙丙橡胶并用胶的共硫化

研究了以过氧化二异丙苯(DCP)/助硫化剂为硫化体系分别硫化天然橡胶(NR)/三元乙丙橡胶(EPDM)以及NR/预硫化EPDM并用胶的性能,考察了EPDM混炼胶的硫化特性,对并用硫化胶进行了.差示扫描量热分析.结果表明,NR/EPDM并用胶在使用DCP/助硫化荆硫化体系时具有较好的共硫化性;EPDM经预硫化后可以将配合剂固定其中,并能增加EPDM的硫化活性,提高了与NR并用胶的共硫化性.     

Numerical study on rubber compounds made of reactivated ethylene propylene diene monomer for fiber reinforced elastomeric isolators

A huge amount of rubber waste coming from tire industry or other sources (eg, weather strips producers) has attracted interest from researchers to investigate the possibility of recycling used rubber for various products, particularly in construction sector. This article presents a series of experimental and numerical investigations to evaluate the feasibility of regenerated synthetic rubber ethylene propylene diene monomer (EPDM) for production of a building seismic isolation system. Four rubber blends using two different sources of regenerated EPDM are considered in this study. The mechanical properties of the recycled rubber under study are evaluated through uniaxial tensile and relaxation tests, considering the accelerated aging effect. Based on several hyperelasticity and viscosity models of rubber available in the literature, several numerical test simulations on rubber compounds and on a prototype of fiber reinforced elastomeric isolators (FREIs) are performed. The test results reveal that the proposed regenerated EPDM compounds can be particularly suitable for the production of unbonded FREIs, especially because they are able to exhibit low/moderate tensile stresses at high-shear strain. The results also show that not all regenerated rubber blends fulfill the durability requirements of rubber for seismic isolation after accelerated aging tests. The durability of the specimens seems to be mainly affected by the choice of the regenerated rubber source.