Ethylene Propylene Diene Terpolymer Blends Research Articles

Transport behavior of aromatic hydrocarbons through high density polyethylene/ ethylene propylene diene terpolymer blends

Membrane based separation technology is currently regarded as a new frontier of chemical engineering and widely used for the purification, concentration and fractionation of fluid mixtures. Polymer blend membranes are promising materials that can overcome the difficulties associated with homopolymer systems and hence the selection of polymer blend membrane as a novel material for various applications is worth probing. Transport properties of aromatic hydrocarbons through a new class of membranes from blends of high density polyethylene (HDPE) and ethylene propylene diene terpolymer rubber (EPDM) have been investigated at different temperatures to understand the effect of physical and chemical nature of the polymer blend on the transport phenomena. The effects of blend ratio, temperature and penetrant size on the sorption properties were studied. The equilibrium solvent uptake decreases with an increase in concentration of HDPE, in the blends. Relationship between transport behavior and the morphology of the system was examined. The mechanism of transport has been analyzed and found that the mode of transport is close to Fickian. The sorption data have been used to estimate the transport coefficients and various kinetic parameters of sorption.

Photoinitiated crosslinking of EPDM/inorganic filler blends and characterization of related properties

Photoinitiated crosslinking of ethylene-propylene-diene terpolymer (EPDM) blends filled with calcium carbonate, talc and calcined kaolin (CK) in the presence of benzil dimethyl ketal as photoinitiator and trimethylolpropane triacrylate as crosslinker and their related properties have been studied by different analytical methods. The results from gel content and heat extension determination show that the efficiency of photocrosslinking of EPDM increases with increasing the content of diene and its molecular weight. The EPDM blends with 100 phr different inorganic fillers can be photocrosslinked to gel content of above 60% by 5 s UV-irradiation under optimum conditions. Under the same conditions of irradiation, the orders of photocrosslinking rate and final gel content are EPDM/CaCO3 > EPDM/talc > EPDM/CK. The data from thermogravimetric analysis, dynamic mechanical thermal analysis, electrical properties, mechanical tests and scanning electron microscopy show that UV irradiation crosslinking apparently enhances the thermal stability, mechanical properties and electrical properties of the photocrosslinked EPDM/inorganic filler samples. Although the attenuated total-reflection FTIR data show that inorganic fillers can promote the surface photo-oxidation of EPDM/inorganic filler samples with increasing the irradiation time, the above related properties of the photocrosslinked EPDM blends irradiated within 5 s are enough to satisfy many applications in the cable industry.

Reactive processing of polymers: Functionalisation of ethylene–propylene diene terpolymer (EPDM) in the presence and absence of a co-agent and effect of functionalised EPDM on compatibilisation of poly(ethylene terephthalate)/EPDM blends

Ethylene–propylene diene terpolymer (EPDM) was functionalized with glycidyl methacrylate (GMA) during melt processing by free radical grafting with peroxide initiation in the presence and absence of a reactive comonomer trimethylolpropane triacrylate (Tris). Increasing the peroxide concentration resulted in an increase in the GMA grafting yield, albeit the overall grafting level was low and was accompanied by higher degree of crosslinking of EPDM which was found to be the major competing reaction. The presence of Tris in the grafting system gave rise to higher grafting yield produced at a much lower peroxide concentration though the crosslinking reactions remained high but without the formation of GMA-homopolymer in either of the two systems. The use of these functionalized EPDM (f-EPDM) samples with PET as compatibilisers in binary and ternary blends of PET/EPDM/f-EPDM was evaluated. The influence of the different functionalisation routes of the rubber phase (in presence and absence of Tris) and the effect of the level of functionality and microstructure of the resultant f-EPDM on the extent of the interfacial reaction, morphology and mechanical properties was also investigated. It is suggested that the mechanical properties of the blends are strongly influenced by the performance of the graft copolymer, which is in turn, determined by the level of functionality, molecular structure of the functionalized rubber and the interfacial concentration of the graft copolymer across the interface. The cumulative evidence obtained from torque rheometry, scanning electron microscopy, SEM, dynamic mechanical analysis (DMA), tensile mechanical tests and Fourier transform infrared (FTIR) supports this. It was shown that binary and ternary blends prepared with f-EPDM in the absence of Tris and containing lower levels of g-GMA effected a significant improvement in mechanical properties. This increase, particularly in elongation to break, could be accounted for by the occurrence of a reaction between the epoxy groups of GMA and the hydroxyl/carboxyl end groups of PET that would result in a graft copolymer which could, most probably, preferentially locate at the interface, thereby acting as an ‘emulsifier’ responsible for decreasing the interfacial tension between the otherwise two immiscible phases. This is supported by results from FTIR analysis of the fractionated PET phase of these blends which confirm the formation of an interfacial reaction, DMA results which show a clear shift in the T gs of the blend components and SEM results which reveal very fine morphology, suggesting effective compatibilisation that is concomitant with the improvement observed in their tensile properties. Although Tris has given rise to highest amount of g-GMA, it resulted in lower mechanical properties than the optimized blends produced in the absence of Tris. This was attributed to the difference in the microstructure of the graft and the level of functionality in these samples resulting in less favourable structure responsible for the coarser dispersion of the rubber phase observed by SEM, the lower extent of T g shift of the PET phase (DMA), the lower height of the torque curve during reactive blending and FTIR analysis of the separated PET phase that has indicated a lower extent of the interfacial chemical reaction between the phases in this Tris-containing blend sample.

Interaction of crosslinked ethylene-propylene-diene terpolymer blends with chlorinated organic penetrants

The sorption and diffusion of halogenated hydrocarbon penetrants through different ethylene–propylene–diene terpolymer (EPDM) blends, such as EPDM/natural rubber, EPDM/bromobutyl rubber, and EPDM/styrene butadiene rubber (50/50 w/w), were studied. The diffusion coefficient of halogenated penetrants fell in the range 1.5–14.52 × 10−7 cm2/s in the temperature range of 25–60°C. Transport data were affected by the nature of the interacting solvent molecule rather than its size and also by the structural variations of the EPDM blends. 1,2-Dichloroethane showed a lower mass uptake compared to other penetrants. The temperature dependence of the transport coefficient was used to estimate the activation parameters, such as the activation energy of diffusion (ED) and the activation energy of permeation (Ep) from Arrhenius plots. The activation parameters for ED of aliphatic chlorinated organic penetrants was in the range 7.27–15.58 kJ/mol. These values fell in the expected range for rubbery polymers, well above their glass-transition temperature. Also, the thermodynamic parameters, such as enthalpy and entropy, were calculated and fell in the range 2–15 kJ/mol and 3–54 J/mol/K, respectively. Both first- and second-order transport kinetics models were used to investigate the transport kinetics, and first-order kinetics were followed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1366–1375, 2003

Mill processability of brominated isobutylene‐co‐paramethyl styrene and its blends with ethylene propylene diene terpolymer (EPDM) in the continuous milling operation

AbstractThe milling behavior of brominated isobutylene‐co‐paramethylstyrene (BIMS), ethylene propylene diene terpolymer (EPDM), and their blends was investigated over a range of temperatures and friction ratios using the continuous milling operation. At 30 °C, BIMS forms a loose nervy appearance and, as the temperature is increased to 90 °C, it gradually forms a tight elastic band. EPDM forms a loose band at all temperatures and friction ratios studied. For different blends of BIMS and EPDM, the milling behavior changes from a tight elastic band to a loose bagging band on increasing the EPDM content. Addition of different fillers results in lowering of the tendency to go to the back roll, even at lower temperatures. In all the filled systems, a smooth, regular, and tight elastic band is obtained at all the temperatures and friction ratios studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1484–1495, 2002

Mill processability of brominated isobutylene‐co‐paramethylstyrene and its blends with EPDM

AbstractMilling behavior of brominated isobutylene‐co‐paramethylstyrene (BIMS) and its blends with ethylene propylene diene terpolymer (EPDM) rubber, was investigated over a range of temperatures and friction ratios in a drop mill operation. BIMS showed striking changes, that is, from a loose nervy band to a tight elastic band, as the temperature of the rolls was increased from 30°C to 90°C. For EPDM a loose band was observed at all temperatures and friction ratios studied. For the blends of BIMS and EPDM, the milling behavior changed from a tight elastic band to a loose bagging band on increasing the EPDM content. The critical nip gap (CNG), at which the front‐to‐back roll (F–B) transition occurred, was also measured. BIMS showed a much higher value of CNG than that of EPDM, indicating that the former had a significantly higher tendency for F–B transition than the latter material. For different blends of BIMS and EPDM, the CNG decreased on increasing the EPDM content, indicating a decrease in the tendency for F–B transition. The results were explained in terms of the rubber‐to‐metal adhesion and the viscosity of the polymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1483–1494, 2001

Properties of dynamically vulcanized EPDM and LLDPE blends

The tensile, rheological, and thermal properties of dynamically vulcanized ethylene–propylene–diene terpolymer (EPDM) and linear low-density polyethylene (LLDPE) blends were reported along with their crystalline structure and morphology. The EPDM/LLDPE blends were prepared in a laboratory internal mixer by simultaneous blending and vulcanization. Vulcanization was performed with dicumyl peroxide. For comparison, linear LLDPE/EPDM blends were also prepared. In comparison to the linear blends, dynamically vulcanized blends showed higher tensile strength and modulus and exhibited improved compatibility. It was found, however, that the crystal structure of LLDPE was not changed by the inclusion of EPDM and the dynamic vulcanization process. © 1996 John Wiley & Sons, Inc.

Mechanical properties of blends of EPDM with NR-cellulose II system

There is an ever increasing technological interest in the use of blends of dissimilar rubbers to improve specific properties of vulcanizates. In this work the system natural rubber (NR) and cellulose II (regenerated cellulose) was mixed with EPDM (ethylene-propylene-diene terpolymer). For reference, pure gum mixtures EPDM/NR were also prepared. The incorporation of cellulose II to NR was based on a technique already developed in this Institute according to which it was possible to observe that the composite consisting of 15 phr of cellulose II in NR (NR-15 phr Cell II) had shown the best mechanical properties. The NR-15 phr Cell II masterbatch was then mixed in different amounts to EPDM in a roll mill and the mechanical properties of the resulting compositions were studied. Two types of EPDM were used and the results were analysed as for the influence of both types of EPDM as well as the relative amounts of EPDM and NR-Cell II system in the blends.

Structure and properties of dynamically cured EPDM and ionomer blends

AbstractThe structure and properties of dynamically cured ethylene‐propylene‐diene terpolymer (EPDM) and ionomer blends have been studied. The blends were prepared in a laboratory internal mixer, where EPDM was cured under shear in the presence of ionomer with dicumyl peroxide (DCP) under different shear conditions. The effects of EPDM/ionomer compositions, DCP concentration and the intensity of shear mixing were investigated using capillary rheometer, differential scanning calorimeter (DSC) and scanning electron microscopy (SEM) techniques. Two kinds of poly(ethylene‐co‐methacrylic acid) ionomers containing different metal ions(Na+ and Zn++) were compared and the effect of the metal ion type for neutralization was considered. The Zn‐neutralized ionomer showed better miscibility with EPDM than the Na‐neutralized ionomer. It is concluded from the rheological properties, crystallization behavior and morphology that the dynamically cured EPDM and Zn‐ion ionomer blends show the behavior of a thermoplastic interpenetrating polymer network (IPN).