Propylene Rubber Research Articles

Organoclay as a Filler for Vulcanisates Based on Ternary Ethylene–Propylene Rubber

Organoclay as a Filler for Vulcanisates Based on Ternary Ethylene–Propylene Rubber

Morphology evolution during cooling of quiescent immiscible polymer blends: matrix crystallization effect on the dispersed phase coalescence

The influence of the matrix crystallization on the coalescence of the dispersed phase particles, in quiescent immiscible polymer blends, is a topic that is scientifically addressed scarcely. The coarsening of the phase structure that is induced by the matrix crystallizing domains was studied using the well-established system comprising a polypropylene and an ethylene–propylene rubber (PP/EPR blends). This subject is of great importance as the effectiveness in the toughening of PP is directly determined by the EPR particle size. Cooling experiments were commenced for resolving the correlation among the imposed cooling conditions, the formed matrix crystalline morphology, and the coalescence of the dispersed phase particles. A confirmation of the profound effect of the PP crystallization on the coalescence of EPR particles was undoubtedly obtained. The contribution of the crystallization to the coalescence of the dispersed phase particles is largest at a finite rate of cooling. A thorough discussion regarding the observed effects, encompassing a potential rejection or an engulfing of the dispersed phase particles by the growing crystallites, was undertaken.

자동차용 고무호스의 진동 절연성능 향상에 관한 연구

We considered an approach in terms of materials for improvement of insulation performance of vehicle rubber hoses. Ethylene propylene rubber(EPDM) for heater hoses in cooling system and acrylic rubber(AR) for intercooler hose in intake system were chosen for mixing for the vibration and noise performance. We modified EPDM and AR through changing compound of base polymer, reinforcement fillers and additives. Dynamic mechanical analysis(DMA) was used to measure viscoelastic properties such as shear modulus and loss factor($tan{\delta}$). Vehicle acceleration test was also conducted to observe indoor changes in insulation performance of hoses.

The Grinding of Ethylene–Propylene Rubber by the High-Temperature Shear Strain Method

The Grinding of Ethylene–Propylene Rubber by the High-Temperature Shear Strain Method

Structural Dynamic Analysis of Polymer Blends Containing Additives of Polyurethane Nature in Different Phase Aggregate States

A comparative analysis by the method of NMR relaxometry of the structural dynamic state of blends of chlorosulphonated polyethylene and ternary ethylene–propylene rubber, containing additives of polyurethane nature in the form of a liquid oligomer and a powder polymer filler, indicates their participation in chemical reactions and processes of phase formation that occur in three-component polymer composites as they are prepared.

Application of Low Frequency Dielectric Spectroscopy to Estimate lifetime of Low-Voltage EPR Insulation

This paper deals with the application of integral values of dielectric spectroscopy as the characteristic values from 10Hz to 1Hz for estimating the lifetime of low-voltage ethylene propylene rubber( EPR) insulation cables aging in the lab. The elongation-at-break and the dielectric dissipation factor (tanδ) were measured to study the characteristics of curve and to analyze sensitive measurement range. Based on the failure criterion of elongation-at-break, the correlation between the mechanical and dissipation curve was investigated and the effectiveness among three ways to assume values of dielectric dissipation factor was compared. Meanwhile, a time multiplicative shift factor was found with the same characteristics value at different aging temperatures and a prediction equation after selected reference temperature was obtained. Combined with integral equation of the deterioration tendency under reference temperature, a life model of dielectric dissipation factor integral for insulation material was derived. Results showed that testing parameters on integral value of tanδ had a contrary tendency with elongation-at-break and reflected the degradation trend in sensitive range within 10Hz~1Hz. Compared life model calculation results with measurements of cable in field, the measurement error was 3.33%. It had been found that this method could effectively evaluate the aging lifetime of low-voltage cable EPR insulation materials.

Synthesis of nanosized ethylene–propylene rubber latex via polyisoprene hydrogenation

AbstractNanosized ethylene–propylene rubber (EPM) latex with a particle size of 47 nm was synthesized via an alternative route consisting of isoprene (IP) polymerization followed by hydrogenation. First, the IP monomer was polymerized by differential microemulsion polymerization to obtain polyisoprene (PIP) rubber latex with a particle size of 42 nm. The structure of synthetic PIP was hydrogenated at the carbon–carbon double bonds to produce an ethylene–propylene copolymer by diimide reduction in the presence of hydrazine and hydrogen peroxide using boric acid as promotor. The degree of hydrogenation was determined by proton nuclear magnetic resonance (1H‐NMR) spectroscopy and the structure of the ethylene–propylene copolymer was identified by 13C‐NMR spectroscopy. In nanosized PIP hydrogenation, the hydrogenation level was found to be increased by boric acid addition. An EPM yield of 94% was achieved using a hydrogen peroxide : hydrazine ratio of 1.5 : 1. The EPM produced from PIP has high thermal stability with the maximum decomposition temperature of 510°C and a glass transition temperature of ‐42.4°C close to commercial ethylene–propylene diene rubber. Dynamic mechanical analysis indicated that EPM had a maximum storage modulus due to the saturated carbons domains of the ethylene segments in the polymer chains. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Coalescence in quiescent polymer blends with a high content of the dispersed phase

Coalescence in molten quiescent polymer blends induced by van der Waals forces is studied theoretically. Interaction between a droplet and its nearest neighbor keeping spherical shape during drainage of the matrix trapped between them is considered. It is assumed that droplets with time dependent radius R or effective droplets with radius R+hc/2, where hc is the critical inter-droplet distance for breakup of the matrix trapped between them, are randomly distributed in the blend through the whole course of the coalescence. Various approaches to calculation of the average time of coalescence, tc (calculation with preaveraged distance between a droplet and its nearest neighbor at the start of coalescence, h0, direct averaging of tc and averaging coalescence frequency, 1/tc) are compared. Calculated dependence of R on the time of coalescence, t, is compared with experimental results for polypropylene/ethylene–propylene rubber (PP/EPR) blends with EPR content from 15 to 30wt.%. Calculations using average h0 and direct averaging of tc lead to more-less linear dependence of R3 on t. Bare averaging of 1/tc leads to a steeper than linear dependence of R3 on t and to unreasonably high rate of the coalescence; averaging of 1/tc with exclusion of pairs with elapsed coalescence time leads to decreasing rate of R3 growth but unreasonably low rate of coalescence. Theories based on the concept of effective droplet radius give smaller differences among various methods of calculations of tc than the theories assuming random distribution of the droplets. Experimental results show decreasing slope of R3 vs. t dependence, especially for a higher content of dispersed EPR. Theories using average h0 or direct averaging of tc predict somewhat smaller rate of coalescence than that experimentally determined for PP/EPR blends. Reasons of these differences are discussed.

The Evolution of Medium Voltage Power Cables

This article introduces a survey on the state-of-the-art and the technological progress in medium-voltage (MV) power cables for distribution systems. At present, MV cable insulation technology is characterized by a changeover from the conventional lapped-paper, paper-insulated laminated (PIL), polyvinyl chloride (PVC), crosslinked polyethylene (XLPE) to tree-retardant cross-linked polyethylene (TRXLPE), and ethylene propylene rubber (EPR). The former types have many disadvantages such as high dielectric loss, high operating cost, and low power handling capability.

Enhancement of rubber–carbon black interaction by amine‐based modifiers and their effect on viscoelastic and mechanical properties

AbstractImprovement in rubber–filler interaction is desirable for rubber technologists due to its influence on numerous properties of rubber compounds and vulcanizates. In practice, there are coupling agents commercially available for the improvement of silica–rubber interaction. Surprisingly, only a limited number of works have been focused on interaction enhancement between carbon black (CB) and rubber. Thus, in the research presented in this article, attempts to improve interaction between ethylene–propylene rubber (EPM) and carbon black (CB) have been made by the use of either p‐phenylene diamine (p‐PDA) or N‐tert‐butyl‐2‐benzothiazole sulfenamide (TBBS) as an interaction modifier. Bound rubber content (BRC), used as an indicator for rubber–filler interaction and viscoelastic behavior of CB masterbatches and CB‐filled EPM compounds were investigated and correlated. Results from the measurement of BRC in the CB masterbatches revealed that p‐PDA was more effective in the enhancement of rubber–CB interaction than TBBS. Such improved interaction led to a decrease in magnitude of CB percolation (Payne effect). In respect of viscoelastic behavior, the interaction modifiers affected G′ only in the small strain region (<1% strain) by slightly raising the value of G′. However, as strain was increased (≥1%), G′ for all compounds was coincident implying a disruption of weak interaction between CB and rubber. In the case of EPM vulcanizates, p‐PDA yielded greater enhancement in mechanical properties than TBBS. The results of BRC, viscoelastic behavior, and mechanical properties were apparently in good agreement. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Quality assessment of recycled and modified LDPE/PP blends

An experimental study was conducted to investigate the morphology, thermal and mechanical properties of recycled polyolefin blends with different prehistory modified with ethylene propylene rubber (ethylene-propylene diene monomer (EPDM)) using the differential scanning calorimetry (DSC), wide angle X-ray scattering, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope and mechanical methods. The efficiency of the modification was investigated as a function of the modifier content in the range from 7 wt% to 15 wt%. DSC results show that the single polymers are not clean material and contain some quantity of another polyolefins. In the processing and exploitation conditions, there is an increase in imperfect crystals in the postconsumer waste polypropylene. FTIR provides clear evidence about the oxidative processes and mechanical destruction during exploitation and blending. The obtained results proved that the technological and postconsumer wastes could be successfully reused as blends by the addition of EPDM.

Adhesion between polyethylenes and different types of polypropylenes

Interfacial entanglement and co-crystallization are identified to cause adhesion. Adhesion between polyethylene and different types of polypropylenes (PPs), including impact-modified PP isotactic PP and ethylene-propylene random copolymers, was increased with concentration of ethylene or ethylene–propylene rubber and faster cooling in co-extrusion. A more miscible interface is the key for improved adhesion.

Smart Materials Based on Magnetorheological Composites

Magnetorheological elastomer composites (MREs) based on different magnetoactive fillers such as: carbonyl iron powder (CIP), gamma iron oxide (γ-Fe2O3), micro-and nanosize Fe3O4 are reported and studied. MREs were obtained from various elastomer matrixes such as: ethylene propylene, acrylonitrile butadiene, silicone, ethylene-octene and polyoctenamer rubbers. To align particles in elastomer, cross-linking process took place in magnetic field. Effect of the amount of ferromagnetic particles and their arrangement on the microstructure and properties in relation to the external magnetic field was examined. The microstructure, magnetic and magnetoreological properties of compositions were investigated with scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and ARES Rheometer with magnetic device. Cross-linking density and mechanical properties of the composites were also studied. It was found that microstructure anisotropy has significant effect on the properties of magnetorheological elastomers. Moreover, different amount of magnetoactive fillers influence mechanical and magnetic properties of the vulcanizates. Many essential conclusions occur after application the wide variety of elastomer matrixes filled with different ferromagnetic particles in the context of preparation process of smart materials based on magnetorheological elastomer composites.

Physicomechanical study of random polypropylene filled with treated and untreated nano-calcium carbonate

Random polypropylene copolymer is blended with 2–10% nano-calcium carbonate (nCaCO3) with and without maleic anhydride-grafted ethylene–propylene rubber ([EPR] MA- g-EPR) using two different titanate- and silane-coupling agents. The nanocomposites were prepared with fatty acid (oleic and stearic acid) surface-treated and -untreated nCaCO3 and random polypropylene. Surface-treated nCaCO3 and EPR (MA- g-EPR) were used as a modifier in nanocomposites and characterized with the help of X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. The physicochemical properties like density, melt flow index and heat distortion temperature were evaluated beside their mechanical properties (tensile, flexural and impact strength). It was found that the favorable surface development is taking place at the interface of coupling agent and surface-treated nCaCO3, and this linkage is responsible for tensile properties. The untreated nCaCO3 shows more reinforcement with matrix for the reason that there is no long alkyl group present at the interface. Beyond a certain limit, increased trends of nCaCO3 in composite do not show more reinforcing effect due to agglomeration of nCaCO3.

Remaining life prediction of I&C cables for reliability assessment of NPP systems

Abstract Instrumentation and control (I&C) cables are one of the most important components in nuclear power plants (NPPs) because they provide power to safety-related equipment and also to transmit signals to and from various controllers to perform safety operations. I&C cables in NPP are subjected to a variety of aging and degradation stressors that can produce immediate degradation or aging-related mechanisms causing the degradation of cable components over time. Although, there exits several life estimation techniques, currently there is no any standard methodology or an approach toward estimating the time dependent reliability of I&C cables that can be directly used in probabilistic safety assessment (PSA) applications. Hence, the objective of this study is to develop an approach to estimate and confirm the continued acceptable margin in cable insulation life over time subjected to aging. This paper presents a framework based on the structural reliability theory to quantify the life time of I&C cable subjecting to thermal aging. Since cross-linked polyethylene (XLPE) cables are extensively being used in Indian NPPs, the remaining life time evaluations have been carried out for a typical XLPE cable. However, the methodology can be extended to other cables such as polyvinyl chloride (PVC), ethylene propylene rubber (EPR), etc.

Thermooxidative degradation of blends based on poly(3-Hydroxybutyrate). Specifics of the process

The relationship between the structure and the kinetics of the thermal oxidation of the poly(3-hydroxybutyrate) — ethylene propylene rubber and polyethylene — poly(3-hydroxybutyrate) systems is studied. For the first system containing 30–50 wt % poly(3-hydroxybutyrate), phase inversion is observed, which affects its reactivity. For the compositions with polyethylene, two stages of oxidation manifest themselves: before and after poly(3-hydroxybutyrate) degradation.

広帯域インピーダンススペクトルのフーリエ解析によるケーブル劣化位置標定の可能性

Since electric cables play important roles such as power supply and information transmission, their degradation may cause serious problems. We have been trying to monitor the degradation of cable insulation by measuring the magnitude and phase angle of the impedance as a function of frequency in a very wide frequency range. The cables tested were insulated with flame-retardant ethylene propylene rubber or special heat-resistant polyvinyl chloride. They were partially damaged by peeling off their insulation layers, or partially aged by heat and γ-rays. The impedance and phase angle were measured from a terminal of the cable. The difference in impedance between the damaged and sound cables is made clear by fast Fourier transform analyses, from which the damaged portion can be located. It can be clearly shown that this method has the potential ability to detect the degradation of cable insulation induced by physical damage, γ-ray irradiation, and thermal aging. © 2013 Wiley Periodicals, Inc. Electr Eng Jpn, 183(1): 1–8, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22384

Influence of the Nature of the Cyclic Component in the Composition of Ternary Ethylene–Propylene Rubber on the Structural and Dynamic State of Blends with Chlorosulphonated Polyethylene

NMR relaxometry showed that, in spite of its small proportion in the composition of the macrochain, corresponding to the “small additive” range (≤5 parts), the cyclic component has a considerable effect on the structural and dynamic state of ternary copolymeric ethylene–propylene rubber in a blend with chlorosulphonated polyethylene owing to the topochemical processes occurring during mixing of the polymers. The results obtained also indicate the most probable or stable centres of intermolecular interactions of a non-chemical nature that determine the short-range conformational order in the given blends.

Calcium carbonate (CaCO3) nanoparticle filled polypropylene: Effect of particle surface treatment on mechanical, thermal, and morphological performance of composites

AbstractThe present study was aimed to see the effect of surface treatment on nanocomposites with different fatty acids (stearic acid and oleic acid) having two different coupling agents (titanate and silane). Nanocomposites were prepared via melt mixing in Haake 90 twin screw extruder. The characterization of nanocomposites had been carried out using various advance analytical techniques such as dynamic mechanical analysis, thermogravimetric analysis, heat distortion temperature, melt flow index, and scanning electron microscopy. The strength and stiffness were also improved with the incorporation of maleic‐anhydride grafted ethylene propylene rubber in PP/Nano‐CaCO3 nanocomposites. The tensile, flexural, and impact strength properties of PP/MA‐g‐EPR/treated‐CaCO3 and untreated nanocomposites were determined. These studies revealed that stearic acid treated nanofiller filled composites had better properties than those of untreated and oleic acid treated nanofiller filled composites. The SEM studies demonstrated that the dispersion and distribution of Nano‐CaCO3 (nCaCO3) particles within the polypropylene matrix were dependent on the nature of surface treating agents. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Development of compatibilized SBR and EPR nanocomposites containing dual filler system

The study described in this paper is an analysis of the role of a compatibilizer for dispersing organically modified nanoclay in styrene butadiene rubber (SBR) and ethylene propylene rubber (EPR) matrices. The normal mixing of non-polar rubbers and organically modified nanoclay may not lead to improved distribution of the nanofiller in the rubbery matrix. Hence, a polar rubber such as epoxidized natural rubber (ENR) can be used as a compatibilizer for dispersing nanoclay in the non-polar rubber matrices. ENR–organically modified nanoclay composites (EC) were prepared by solution mixing. The nanoclay used in this study is Cloisite 20A. The obtained ENR–nanoclay composites were incorporated in SBR and EPR matrices along with carbon black. The morphological studies proved the intercalation of nanoclay platelets in ENR and further incorporation of EC in SBR and EPR matrices leads to partial exfoliation of nanoclay platelets. A curing study demonstrated faster scorch time, cure time and increased maximum torque for the compatibilized SBR and EPR nanocomposites containing a dual filler system compared to the control. Dynamic mechanical thermal analysis showed increase in storage modulus for the SBR and EPR compounds containing dual fillers compared to rubber compounds containing pure and single filler. The same compounds show substantial improvement in mechanical properties. The tensile fractured surface of the rubber compounds containing single and dual filler observed by scanning electron microscopy, (SEM) showed highly rough and irregular fracture paths, which proved the physical interaction between filler and rubber.