Tack and Green Strength of Blends of Bromobutyl and EPDM Rubbers. I. Unfilled Gum Blends

Polymer blends are gaining importance in recent years because they provide a compromise of properties. In this paper, tack and green strength of several blends of EPDM and bromobutyl rubbers (BIIR) have been studied over a wide range of temperaures, contact times and rates.

Tack increases with increase in contact time and with increase in contact temperature up to 47°C for a particular blend. At a much higher temperature the tack strength falls gradually. Green strength increases with increase in bromobutyl content and decreases with temperature. Tack index, a ratio of tack strength divided by the cohesive strength under the same geometry, decreases slowly with the test temperature. At a 50:50 ratio of BIIR:EPDM, the two rubbers form an interpenetrating network as observed under the phase contrast microscope.     

Tack and Green Strength of Blends of Bromobutyl and EPDM Rubbers. I. Unfilled Gum Blends

Polymer blends are gaining importance in recent years because they provide a compromise of properties. In this paper, tack and green strength of several blends of EPDM and bromobutyl rubbers (BIIR) have been studied over a wide range of temperaures, contact times and rates.

Tack increases with increase in contact time and with increase in contact temperature up to 47°C for a particular blend. At a much higher temperature the tack strength falls gradually. Green strength increases with increase in bromobutyl content and decreases with temperature. Tack index, a ratio of tack strength divided by the cohesive strength under the same geometry, decreases slowly with the test temperature. At a 50:50 ratio of BIIR:EPDM, the two rubbers form an interpenetrating network as observed under the phase contrast microscope.     

Effect of silanized silica nanofiller on tack and green strength of selected filled rubbers

BACKGROUND: Tack and green strength of filled and gum (unfilled) natural rubber (NR), poly(styrene‐co‐butadiene) rubber (SBR), polybutadiene rubber (BR) and (SBR‐BR) blend with different loadings of reinforcement agent, silanized silica nanofiller (Coupsil 8113), were studied and the results compared and discussed. RESULTS: It was found that silica was fully dispersed in rubber matrix after 13 min of mixing. In addition, with some exceptions for NR and (SBR‐BR) blend, filler loading decreased the tack strength of the studied filled rubbers. Green strength and Mooney viscosity increased with filler loading for all studied filled rubbers but with different rates and amounts. The optimum filler loadings for NR and (SBR‐BR) filled blend were 30 and 10 phr, respectively. Tacks of NR filled rubbers were much higher than those of synthetic filled rubbers. CONCLUSION: It was concluded that filler loading alters substantially the tack and green strength of the rubbers under investigation. Copyright © 2009 Society of Chemical Industry     

溴化丁基橡胶/氯化丁基橡胶并用胶的制备及性能

用差示扫描量热仪测定了溴化丁基橡胶/氯化丁基橡胶(BIIR/CIIR)共混胶的玻璃化转变温度,研究了不同并用比(质量比)共混胶的相容性、硫化特性以及力学性能和热稳定性。结果表明,不同并用比的BIIR/CIIR共混胶仅有1个玻璃化转变温度,表明BIIR和CIIR具有良好的相容性;BIIR的焦烧时间比CIIR短,共混胶的焦烧时间介于BIIR和CIIR之间,而正硫化时间比BIIR和CIIR都长;共混硫化胶的拉伸强度、撕裂强度均优于BIIR和CIIR硫化胶,热稳定性与BIIR相当;当BIIR/CIIR的并用比为80/20时,共混硫化胶的综合性能最好。     

Sorption and diffusion of n-alkanes into bromobutyl rubber membranes

Sorption and diffusion of n-alkanes into bromobutyl rubber membranes were investigated in the temperature interval 25–60°C by a sorption gravimetric method. The Fickian diffusion equation was used to calculate the diffusion coefficients, which were dependent on the size of the alkanes, their interactions with the chain segments of the polymer and temperature. The diffusion coefficients varied from 0.34×10^?7 cm²/s (n-hexadecane) to 9.94×10^?7 cm²/s (n-hexane). The activation energy for diffusion varied from 14kJ/mol (n-hexane) heptane to 2.0kJ/mol for n-hexadecane. The sorption/swelling results are discussed in terms of first and second order kinetic equations. The molar mass between chain-entanglement-crosslinks was estimated from swelling data. The experimental and calculated results showed a systematic dependence on the increasing size of the alkanes. None of the solvents showed any degradative effects on the polymer.     

Mechanical properties,thermal stability,gas permeability,and phase morphology in natural rubber/bromobutyl rubber blends

This work was performed to relate the morphological features and all important properties of the natural rubber (NR) and bromobutyl rubber (BIIR) blends containing hybrid fillers. The BIIR content was varied from 0 to 100 wt%. It is found that tensile and tear strength, hardness as well as resilience of blends tend to decrease with increasing BIIR loading. Regarding the blend morphology, phase inversion is observed when BIIR loading is >50 wt % where BIIR becomes a continuous phase. This result coincides with the marked improvement of thermal stability of the blends determined using thermogravimetric analysis and heat ageing method. Interestingly, that, the gas permeability of blends markedly reduces with an increase in BIIR loading up to 40 wt % when the relatively large elongated particles of BIIR dispersed phase is formed. The results indicate that the relatively large connected structure of the dispersed BIIR can act effectively as a gas barrier. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Tack and green strength of brominated isobutylene-co-p-methylstyrene and its blends

The tack of uncrosslinked gum and filled brominated isobutylene-co-p-methylstyrene (BIMS) was examined as a function of time using the 180° peel geometry. The tack strength showed a 1/4th power dependence with respect to time. The BIMS showed marginally lower tack strength than its non-brominated precursor (IMS). The addition of fillers to the BIMS increased the tack strength as compared to the gum rubber. With increasing filler loading, the tack strength increased up to a certain contact time. A good adhesion between BIMS and ethylene propylene diene terpolymer elastomer (EPDM) was observed due to their similar solubility parameters, whereas adhesion between BIMS and natural rubber (NR) was low. Autohesion studies of different blends of BIMS with EPDM and NR revealed that 70 : 30 BIMS : EPDM and 30 : 70 BIMS : NR blends showed higher tack strength than their constituent polymers. The results could be explained in terms of green strength and compression creep measurements.     

高苯乙烯在三元乙丙橡胶中的应用

文中研究了高苯乙烯对三元乙丙橡胶性能的影响。试验结果表明,随着胶料中高苯乙烯用量的增加,三元乙丙橡胶的硬度、定伸应力增大,拉伸强度、拉断伸长率有所降低。     

丁腈橡胶和三元乙丙橡胶共混体系的结构与性能

研究了NBR/EPDM共混胶料中的相结构与并用橡胶最重要的性能(力学特性、耐臭氧性、耐油性)的相互关系,发现耐臭氧性良好的EPDM与耐油性NBR之间不发生共硫化,它实际上是一种弹性填料。只有在EPDM形成立体网络时,硫化胶的耐油性才能达到最大值。另外,指出了EPDM在体系中的最佳用量。     

镀镍石墨/EPDM导电橡胶复合材料的性能研究

研究了镀镍石墨用量对EPDM导电橡胶复合材料性能的影响,遴选出了最佳硅烷偶联剂,并研究了其用量对复合材料导电稳定性的影响。结果表明,随着镀镍石墨用量的增加,复合材料的体积电阻率逐渐降低,当用量超过240phr时,体积电阻率能降到10Ω?cm以下。A137是一种有效的硅烷偶联剂,当用量为9phr时,材料的各项性能较好。     

Comparative behavior of in situ silica generation in saturated rubbers: EPDM and hydrogenated natural rubber

Role of carbon‐carbon double (C?C) bonds content and their position in ethylene‐propylene diene ter‐polymer (EPDM), hydrogenated natural rubber (HNR) and natural rubber (NR) on in situ silica formation using tetraethoxysilane (TEOS) as a silica precursor is comparatively investigated. Glass transition temperature (T_g ) reflecting rubber chain flexibility is found as an important factor for in situ silica generation via swelling method. Despite of similar solubility parameters, NR has higher TEOS‐swelling degree resulting in the higher in situ silica content (30.8 phr) than EPDM (3.50 phr) and HNR (10.4–17.6 phr) due to the higher T_g of EPDM and HNR providing the less chain flexibility to be swollen in TEOS solution. The morphological analysis implies that C?C bonds in saturated rubbers may be agglomeration sites for in situ silica particles. For practical applications, saturated rubbers containing in situ silica/NR vulcanizates showed the improvement of mechanical properties and resistance of thermal and ozone degradation. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44748.     

A comparison of the properties of rice husk ash,silica, and calcium carbonate filled 75 : 25 NR/EPDM blends

The effects of incorporation of three different fillers, i.e., rice husk ash (RHA), silica, and calcium carbonate (CaCO₃), over a loading range of 0–60 phr on the curing characteristics, processability, mechanical properties, and morphology of 75 : 25 natural rubber (NR)/ethylene‐propylene‐diene monomer (EPDM) blends were studied using a conventional vulcanization system. Filler loading and type influence the processability of the blends in which RHA and CaCO₃ offer better processing advantage over silica. The best improvement in the tensile and tear strength and abrasion resistance of the 75 : 25 NR/EPDM blends with additional fillers was achieved when filled with silica. However, RHA and CaCO₃ were better in resilience property compared to that of silica. The RHA filled blends showed higher failure properties and abrasion resistance but lower ozone resistance than that containing CaCO₃. Scanning electron micrographs revealed that the morphology of the blend filled with silica is finer and more homogenous compared to the blend filled with RHA and CaCO₃. According to these observations, RHA can be used as a cheaper filler to replace CaCO₃ in rubber blends where improved mechanical properties are not so critical. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

EPDM/NR并用胶的复合交联

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，研究并用比和复合交联体系对胶料的硫化特性、物理性能和耐热老化性能的影响。结果表明，在大部分并用比下，复合交联可以改善胶料的硫化特性；在硫化剂DCP和助交联剂TAIC的用量均为2份、EPDM／NR／ENR并用比为30／68．5／1．5时，并用胶的物理性能优良；以NR为主的并用胶在复合交联时硫化剂DCP和助交联剂TAIC的用量宜取1～2份。     

Analysis of the effects of the polymerization route of ethylene‐propylene‐diene rubbers (EPDM) on the properties of polypropylene‐EPDM blends

A comparative study of two ethylene‐propylene‐diene rubbers (EPDM) polymerized by both conventional (Ziegler–Natta catalysts) and new techniques (metallocene catalysts) is presented. For this purpose, thermoplastic elastomers based on isotactic polypropylene (iPP) and EPDM blends at different percentages were prepared and their properties examined. In particular, the processing behavior and mechanical properties are reported. So, the flow properties analyzed by torque value, melt index, and rheological study reveal that the blends containing EPDM synthesized by metallocene catalyst present a smaller viscosity, thus offering better processing behavior. On the other hand, the mechanical properties show that metallocene EPDM rubbers give rise to more elastic materials with a higher deformation at break and resilience as well as a lower compression set. Moreover, the effectiveness of these innovative EPDM rubbers as impact modifiers for PP is demonstrated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 25–37, 2002     

改性EPDM中冷器出气胶管的开发及应用

介绍了汽车柴油发动机中冷器出气胶管的特点,比较了硅橡胶与三元乙丙橡胶的性能特征。通过产品结构设计、材料配方和成型工艺研究,开发能够代替硅胶管的低成本的改性EPDM中冷器出气胶管。经过对研制胶管的全面性能测试、装车路试认定、装配工艺和使用情况评价,新型胶管完全满足产品的技术性能和使用要求,其开发应用能够大幅度降低采购成本,具有显著的经济效益。     

Tack and Shear Strength of Adhesives Prepared from Styrene-Butadiene Rubber (SBR) Using Gum Rosin and Petro Resin as Tackifiers

Tack and shear strength of styrene-butadiene rubber (SBR)-based pressure-sensitive adhesive were studied using gum rosin and petro resin as the tackifiers. The concentration of the tackifying resin was varied from 0 to 100 parts per hundred parts of rubber (phr). Toluene was used as the solvent throughout the experiment. The rolling ball technique was used to measure the tack of the adhesive, whereas, shear strength was determined by a TA-HDi Texture Analyser. Results show that the tack of the adhesive increases with increasing tackifier loadings for both tackifier systems. However, shear strength indicates the reverse behavior with increasing resin content, an observation which is attributed to the decrease in cohesive strength as the tackifier concentration is increased. Both tack and shear strength of the adhesives increases with molecular weight of SBR. Adhesive containing petro resin consistently exhibits higher values than the gum rosin system due to better wettability and compatibility in the former system.     

硅橡胶／三元乙丙橡胶泡沫合金的研制

研究了硅橡胶／三元乙丙橡胶（Ｑ／ＥＰＤＭ）共混,发泡的配方与成型工艺,对补强剂,发泡剂,硫化剂,成型温度,时间等因素对泡沫材料的密度硬度等性能的影响进行了研究。     

Rheological study of EPDM/silicone rubber blends phase inversion and characterization of resultant mechanical and thermal properties

This study was committed to the characterization of the rheological, thermal, mechanical, and morphological properties of ethylene-propylene-diene monomer (EPDM)/silicone rubber (SR) blends. These blends are a potential new class of materials for the insulation of circuits and electrical components that actuate in environments with high heat generation. The blends were produced in a torque rheometer with a Banbury type rotor, varying the concentration of EPDM and SR. Results obtained by capillary rheometry were applied to three theoretical models to analyze the phase inversion threshold, which was confirmed by scanning electron microscopy images. Such analyzes were important to describe the consequence of phase inversion on the evaluated properties. It was reported that the increase in SR concentration decreased the elastic modulus and increased the tensile strength of the blends. For blends with composition situated after phase inversion, the SR becomes the matrix, leading to a significant rise in the Vicat softening temperature and reduced thermal conductivity. Such improvements extend the range of applications of these materials as electrical insulators in environments with higher heat generation.     

高岭土填充橡胶共混物的性能及表征

以一种高岭土为增强相,分别填充天然橡胶、丁苯橡胶、顺丁橡胶、丁腈橡胶、三元乙丙橡胶、氯丁橡胶和硅橡胶,制备高岭土/橡胶复合材料,通过力学和热老化性能测试、红外光谱和偏光显微镜测试分析,确定了高岭土在各种橡胶中填充的最佳配比,研究高岭土的用量对橡胶力学性能、热老化性能和相容性上的影响,并与白炭黑填充橡胶进行比较。实验表明,除扯断伸长率外,高岭土/橡胶具有优异的力学和耐热性能,高岭土与橡胶有较好的相容性,且适合刚性橡胶的补强。     

Recycling of EPDM waste. I. Effect of ground EPDM vulcanizate on properties of EPDM rubber

Processing, cure characteristics, and mechanical properties of EPDM rubber containing ground EPDM vulcanizate of known composition were studied. Mooney viscosity increases and Mooney scorch time decreases by the addition of the ground vulcanizate. At higher loadings of the ground rubber, the maximum rheometric torque decreases. On addition of ground waste, stress–strain properties and tear resistance increase, whereas heat buildup marginally increases, resilience marginally decreases, low‐strain modulus remains constant, and abrasion resistance decreases. The interplay between the filler effect of the ground EPDM and the crosslink density changes of the EPDM matrix is believed to be the reason for the variation in mechanical properties. It is believed that sulfur migration occurs from the raw EPDM matrix (R‐EPDM) to the ground waste EPDM (W‐EPDM) particle while accelerator migration occurs from W‐EPDM to R‐EPDM. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3293–3303, 2001