Ethylene-propylene-diene Terpolymer Content Research Articles

Effect of electron beam irradiation on thermal and crystallization behavior of PP/EPDM blend

The irradiation stability of ethylene-propylene diene terpolymer (EPDM)/ polypropylene (PP) blends is studied in an attempt to develop radiation compatible PP/EPDM blends suitable for medical applications. The PP/EPDM blends with mixing ratios of 80/20, 50/50/ 20/80 were prepared in an internal mixer at 165°C and a rotor speed of 50rpm followed by compression molding. The blends and the individual components were irradiated using 3.0MeV electron beam (EB) accelerator at doses ranging from 0 to 100kGy in air and room temperature. Later, the PP/EPDM blends were subjected to gel content, thermal stability, crystallization and dynamic mechanical properties before and after irradiation. Results revealed that the irradiation-induced crosslinking in the PP/EPDM blend increases with the increasing irradiation dose and the EPDM content in the blend. However, the thermal stability of the blends did not show any significant changes upon irradiation. The dynamic mechanical analysis shows that the EPDM rich blend has higher compatibility than PP dominant blends. A further improvement in the blend compatibility found to be achieved upon irradiation.

Structure-Property Relationship in Terms of Dynamic Mechanical Properties of High Energy Radiation Treated Industrially Important Thermoplastic Elastomer Blend

A series of low-density polyethylene (LDPE)/ethylene propylene diene terpolymer (EPDM) blends with various compositions have been prepared by melt mixing followed by injection molding. These specimens are irradiated at 40, 80, 120 and 160 kGy electron beam radiation. The gel content increases with increase in EPDM and as well as EB dose. Storage modulus (E’) and loss modulus (E”) are decreased with increase in EPDM content. Storage modulus continues to increase and loss modulus keeps on decreasing with radiation dose. Interestingly, damping property is found to be more for EPDM rich blends, which again decreases upon irradiation. Morphology of fractured surface of LDPE/EPDM shows that with increase in EPDM content, the size and depth of the cavity becomes larger and deeper indicating higher ductility. But, EB crosslinking makes the surface smoother and the smoothness keeps on increasing with increase in dose rendering stiffness to the samples.

Toughening Effect of Ethylene Propylene DieneTerpolymer-Graft-Styrene-Acrylonitrile Copolymer (EPDM-g-SAN) on SAN Resin

The reaction product EPDM-g-SAN, synthesized by suspension graft copolymerization of styrene (St) and acrylonitrile (AN) in the presence of ethylene-propylene-diene terpolymer (EPDM), was blended with a commercial styrene-acrylonitrile copolymer (SAN resin) to prepare AES blends with high impact strength. The effects of AN mass percentage in the St-AN comonomer mixture (f AN), EPDM mass percentage in the feed of EPDM and St-AN (f EPDM) and reaction time on monomer conversion ratio (CR), grafting ratio (GR), and AES notched Izod impact strength were characterized. The notched Izod impact strength of AES containing 15 wt% EPDM reached its maximum with f AN of 40 wt% and f EPDM of 45 wt%; this was attributed to the polarity of the SAN copolymer obtained being appropriate with that of the SAN resin matrix. The dependences of GR and the notched Izod impact strength of AES containing 25 wt% EPDM on the reaction time were in rough agreement. The effect of EPDM content on the AES notched Izod impact strength indicated that the brittle-ductile transition of AES occurred for an EPDM content from 12.5 to 15 wt%. TEM and SEM analysis showed that the phase structure of AES exhibited a “salami” like structure, and the toughening mechanism of AES was shear yielding of the SAN resin matrix, which endowed AES with excellent toughness.

Fracture study of modified TiO2 reinforced PP/EPDM composite: mechanical behavior and effect of compatibilization

Elastomer-rich thermoplastic polyolefin containing Polypropylene(PP) and Ethylene-Propylene-Diene Terpolymer (EPDM) were studied with a variable EPDM content(0–50 %) in PP. Surface modification of TiO2 was made by using Amino Propyl Trimethoxy Silane APS and Triethyl Amine as coulping agent and surface grafting catalyst respectively with constant stirring at 300 rpm. PP/EPDM/TiO2 ternary composites were obtained after surface modification using twin screw extruder at TiO2 loading of 1 wt.%, 3 wt.% and 5 wt.% respectively using twin screw extruder and optimized. The effect of TiO2 nanoparticle on the mechanical and morphological properties was investigated, which showed improved impact strength and toughness under plane strain condition. Deep fracture study was done at different temperature (−60 to 60 °C) using izod impact test and SENT Test. Fracture stress, fracture energies and brittle to ductile transitions were determined by crack initiation and propagation process which shows that there is a significant increment in the impact and fracture energies at positive temperature. The morphological study of fractured surface of blend and blend nanocomposite has also been investigated employing SEM analysis.

Morphology and properties of PP/EPDM binary blends and PP/EPDM/nano‐CaCO3 ternary blends

AbstractIn this article, the morphology, crystallization, and rheological behaviors of polypropylene (PP)/ethylene‐propylene‐diene terpolymer (EPDM) binary blend and PP/EPDM/calcium carbonate nanoparticles (nano‐CaCO3) ternary blend were investigated. Two processing methods, i.e., direct extrusion and two‐step extrusion, were employed to prepare the PP/EPDM/CaCO3 blend. The influence of EPDM and nano‐CaCO3 respectively on phase morphology and properties of PP/EPDM blend and PP/EPDM/CaCO3 blend were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and dynamic rheometer. The crystallinity and crystallization temperature of PP/EPDM blend were improved in comparison to pure PP due to addition of EPDM, but kept invariable with the increased EPDM loading. As the EPDM content was increased, the mobility of PP molecular chains was weakened. Compared with direct extruded blend, less and finer nano‐CaCO3 was dispersed in matrix of two‐step extruded blend. Accordingly, the increased nano‐CaCO3 in matrix gave rise to a weaker increment in crystallinity and crystallization temperature of two‐step extruded blend, and a later platform of tanδ curve. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Influence of the rubbery phase on the crystallinity and thermomechanical properties of poly(3-hydroxybutyrate)/elastomer blends

Poly(3-hydroxybutyrate) (PHB) is a very promising biopolymer. In order to improve its processability and decrease its brittleness, PHB/elastomer blends can be prepared. In the work reported, the effect of the addition of a rubbery phase, i.e. ethylene–propylene–diene terpolymer (EPDM) or poly(vinyl butyral) (PVB), on the properties of PHB was studied. The effects of rubber type and of changing the PHB/elastomer blend processing method on the crystallinity and physical properties of the blends were also investigated. For blends based on PHB, the main role of EPDM is its nucleating effect evidenced by a decrease of crystallization temperature and an increase of crystallinity with increasing EPDM content regardless of the processing route. While EPDM has a weak effect on PHB glass transition temperature, PVB induces a marked decrease of this temperature thank to its plasticizer that swells the PHB amorphous phase. A promising solution to improve the mechanical properties of PHB seems to be the melt-processing of PHB with both plasticizer and EPDM. In fact, the plasticizer is more efficient than the elastomer in decreasing the PHB glass transition temperature and, because of the nucleating effect of EPDM, the decrease of the PHB modulus due to the plasticizer can be counterbalanced. Copyright © 2010 Society of Chemical Industry

Mechanical, Thermal, and Rheological Properties of EPDM-graft-methyl Methacrylate and Styrene (EPDM-g-MS)/Methyl Methacrylate-Styrene Copolymer (MS Resin) Blends

EPDM-graft-methyl methacrylate and styrene (EPDM-g-MS) were synthesized by solution graft copolymerization of methyl methacrylate (MMA) and styrene (St) onto ethylene-propylene-diene terpolymer (EPDM). EPDM-g-MS/MS resin blends (MES) tht were prepared by melt blending EPDM-g-MS and methyl methacrylate-styrene copolymer (MS resin). The mechanical properties, compatibility, thermal stabilities and rheological properties of MES were studied by the pendulum impact tester and the tension tester, differential scanning calorimetric (DSC), thermogravimetry analysis (TGA), and the capillary rheometry, respectively. The results showed that EPDM-g-MS had an excellent toughening effect on MS resin; the notched Izod impact strength of MES reached 20.7 kJ/m2 when EPDM content in MES was 25 wt%, about 14 times that of MS resin. EPDM-g-MS and MS resin were partially compatible, and the compatibility increased with an increasing MMA/St ratio of EPDM-g-MS. MES had excellent heat-resistance, which increased as the EPDM content in MES and MMA/St ratio of EPDM-g-MS rose. MES melt flow confirmed pseudoplastic flow characteristics. The apparent viscosity (η a ) of MES decreased with an increasing shearing rate (γ) and temperature, but increased with an increasing EPDM content in MES and MMA/St ratio of EPDM-g-MS. The flow activation energy of MES was lower than that of MS resin.

The Effect of Dynamic Vulcanization on the Properties of Polypropylene/Ethylene-Propylene Diene Terpolymer/Natural Rubber (PP/EPDM/NR) Ternary Blend

The effects of dynamic vulcanization on the process development and some properties, such as tensile properties, swelling index, gel content, crystallinity, and morphology, of the polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM)/natural rubber (NR) blends were investigated. Dynamically vulcanized blends show higher stabilization torque than unvulcanized blends. In terms of tensile properties, the tensile strength and tensile modulus (stress at 100% elongation, M100) of the vulcanized blends have been found to increase as compared with the unvulcanized blends, whereas the elongation at break is higher in the blend with richer EPDM content. These results can be attributed to the formation of cross-linking in the rubber phase. The formation of cross-links in the rubber phase has also been proved by swelling index and gel content. The percentage of crystallinity of the blends is decreased by dynamic vulcanization. Scanning electron microscopy (SEM) micrographs from the surface extraction of the blends support that the cross-links occurred during dynamic vulcanization.

Specifics of the structure and mechanical properties of blends of isotactic polypropylene with ethylene-propylene-diene elastomer

The structure of unvulcanized and dynamically vulcanized blends of isotactic PP with ethylene-propylene-diene terpolymer (EPDM) having an EPDM content of 5–85 wt % was studied by means of atomic force microscopy. The systems based on the virgin elastomer and the elastomer plasticized with 50% oligomer were examined. During thermal treatment (molding), the structure of the unvulcanized materials undergoes substantial changes. The morphology of dynamically vulcanized blends containing up to 75 wt % rubber is characterized by a homogeneous distribution of crosslinked rubber particles with a particle size of less than 2 μm in the continuous thermoplastic matrix. During PP blending with the plasticized elastomer, the oligomer diffuses into the thermoplastic phase, with the oligomer being distributed evenly between the blend components. As a result, the stress-strain characteristics of the plasticized systems decline relative to those of the oligomer-free materials. A comparative analysis of the dependence of the elastic modulus on the composition of the blends with the theoretical values obtained in terms of the Kerner, Uemura-Takayanagi, Davies, and Coran-Patel models was performed.

Rheology and phase structure of PP/EPDM/SiO 2 ternary composites

In this article, the rheological properties of polypropylene (PP)/ethylene–propylene–diene terpolymer (EPDM)/silicon dioxide (SiO 2) ternary composites were systematically investigated. Two kinds of nano-SiO 2 particles (with hydrophobic (denoted as A-SiO 2) or hydrophilic (denoted as B-SiO 2)) as well as two processing methods (one-step or two-step) were first employed to prepare PP/EPDM/SiO 2 ternary composites. Then the deep mixing and morphology evolution of polymer composite with mixing time were assessed by rheological method, on the focus of formation of filler-network, and compared with scanning electron microscopy (SEM) observations. Linear viscoelastic behavior was observed for PP/EPDM and PP/SiO 2 binary system, showing no evidence of the formation of filler-network structure. However, a solid-like rheological behavior, which was attributed to the formation of the filler-network structure as confirmed by SEM observation, could be observed in some PP/EPDM/SiO 2 ternary systems, depending on the SiO 2 surface property, processing method and EPDM content. It seemed that SiO 2 with hydrophilic surface was necessary for the formation of filler-network in PP/EPDM/SiO 2 ternary system. Besides, two-step processing method made the solid-like behavior occurred at an earlier stage compared with that of a one-step processing method, also, the higher elastomer content facilitated the formation of the filler-network structure. The results were in good agreement with those reported in our previous publications [Yang H, Zhang Q, Guo M, Wang C, Du R, Fu Q. Polymer 2006;47:2106] [Yang H, Zhang X, Qu C, Li B, Zhang L, Zhang Q, et al. Polymer 2007;48:860].

Effect of EPDM Content on Melt Flow, Microstructures and Fracture Behavior of Dynamically Vulcanized PP/EPDM Blends

Polypropylene (PP)/Ethylene‐propylene‐diene terpolymer (EPDM) blends were dynamically vulcanized with dicumyl peroxide (DCP), using a two‐step method of even dispersion of DCP in EPDM at first and then cross‐linking at elevated temperature. The results showed that though both chain scission and cross‐linking occurred, the cross‐linking reaction predominated in this process and the number of EPDM particles was increased, accompanied with a reduction in particle size and uniform dispersion. Differential scanning calorimetry (DSC) results indicated the existence of PP/EPDM graft copolymer. The essential work of fracture (EWF) results showed that both the specific essential work of fracture (w e ) and the specific plastic work (w p ) increased with increasing EPDM content, the fracture toughness and plastic energy consumption (βw p ) could be improved simultaneously and the ratio of w e and βw p could be controlled by adjusting EPDM and DCP content.

Preparation and characterization of vinyltriethoxysilane grafted ethylene propylene diene terpolymer/linear low density polyethylene (EPDM‐g‐VTES/LLDPE) blends

AbstractGraft polymerization of vinyltriethoxysilane (VTES) onto ethylene‐propylene‐diene terpolymer (EPDM) was carried out in toluene using dicumylperoxide (DCP) as initiator. Effects of various parameters (EPDM content, VTES content, reaction time, reaction temperature and initiator concentration) on the grafting efficiency of VTES onto EPDM were investigated. At the optimum grafting efficiency conditions, EPDM‐g‐VTES was developed by melt mixing in a twin screw extruder and then linear (l), statically vulcanized (s) and dynamically vulcanized (d) blends of EPDM‐g‐VTES with linear low‐density polyethylene (LLDPE) with varying percentage compositions were prepared by melt mixing in the twin screw extruder. The grafting of VTES onto EPDM and its crosslinking was confirmed by FT‐IR. The characterization of mechanical properties such as tensile strength, elongation at break, Young's modulus and hardness, differential scanning calorimetry (DSC) analysis and morphology were studied and compared for the EPDM‐g‐VTES/LLDPE blends. The study reveals that the dynamically vulcanized blend improves the mechanical and thermal properties due to the presence of efficient interaction between component polymers when compared with other blends. Copyright © 2005 John Wiley & Sons, Ltd.

Synthesis of high rubber styrene–EPDM–acrylonitrile graft copolymer and its toughening effect on SAN

AbstractHigh rubber styrene–EPDM–acrylonitrile (AES) was prepared by the graft copolymerization of styrene (St) and acrylonitrile (AN) onto ethylene–propylene–diene terpolymer (EPDM) in n‐heptane/toluene cosolvent using benzoyl peroxide as an initiator. The effects of reaction conditions, such as reaction temperature, initiator concentration, EPDM content, the solvent component, and reaction time, on the graft copolymerization are discussed. In addition, according to the research on mechanical properties of the SAN/AES blend, a remarkable toughening effect of AES on SAN resin was found. By means of scanning electron microscopy, the toughening mechanism is proposed to be crazing initiation from rubber particles and shear deformation of SAN matrix. Uniform dispersion of rubber particles, as shown by transmission electron microscopy, is attributed to the good compatibility of SAN and AES. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 416–423, 2004

Reactive Extrusion of SAN/EPDM Blends

Abstract The blending of styrene-acrylonitrile copolymer (SAN) and three different types of ethylene-propylene-diene terpolymer (EPDM) by reactive extrusion was studied and the free radical initiators: 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane (Luperco 101 XL), 2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3 (Luperco 130 XL), α,α′-di(t-butylperoxy)diisopropyl-benzene (Peroximon F40) and 2,2-azo-di-(2-acetoxy)propane (Luazo AP) were used. Besides, structural characteristics of the obtained blends, some rheological and mechanical properties were also established. The rheological behavior was determined using rheometer and corotating extruder. Measurements of mechanical properties included: tensile strength, impact strength and elongation at break have been made. Blends were separated on its structural components SAN, EPDM, graft (EPDM-g-SAN) and gel content, which were further characterized by solution viscosimetry and IR spectrophotometry. The obtained results elucidate the reactions that occur during extrusion process. The dominant grafting reaction was observed in blends prepared by using a Peroximon F40 as an initiator also showing outstanding mechanical and processing characteristics.

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

Development and characterisation of vinyloxyaminosilane grafted ethylene-propylene-diene terpolymer (EPDM-g-VOS) for engineering applications

A novel and new copolymer of vinyloxyaminosilane grafted ethylene-propylene-diene terpolymer (EPDM-g-VOS) has been synthesised in toluene using dicumyl peroxide as initiator. The grafting efficiency of vinyloxyaminosilane (VOS) onto ethylene-propylene-diene terpolymer (EPDM) has been studied as a function of EPDM content, reaction time, reaction temperature and initiator concentration. Using the optimum grafting efficiency conditions, EPDM-g-VOS has also been developed in a Haake Rheocord-90, torque rheometer. The grafting of vinyloxyaminosilane onto ethylene-propylene-diene terpolymer (EPDM-g-VOS) has been confirmed by Fourier-transform infrared spectroscopy. The mechanical, thermal, and electrical, properties of hot water cured EPDM-g-VOS and peroxide cured EPDM are compared. The mechanical properties of EPDM-g-VOS are decreased due to the flexibility imparted by VOS. However thermal and dielectric properties are increased due to the introduction of VOS onto EPDM as well as the formation of thermally stable three dimensional network through Si–O–Si– linkage.

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

Effect of high density polyethylene addition and testing temperature on the mechanical and morphological properties of polypropylene/ethylene-propylene diene terpolymer binary blends

High density polyethylene (HDPE) was added to the polypropylene (PP)/ethylene-propylene diene terpolymer (EPDM) binary blend, and the effect of testing temperatures on the modulus of elasticity, impact behavior and corresponding fracture morphology was analyzed. Modulus of elasticity generally decreased as the EPDM content increased regardless of the testing temperatures. However, it was found that the modulus of elasticity of PP/EPDM/HDPE ternary blend increased compared to PP/EPDM binary blend when tested at −30 and −60 °C. Notched Izod impact strength changed depending on the testing temperatures, however, there was not much difference between binary and ternary blends up to 20 wt% EPDM. However, at more than 30 wt% EPDM content, ternary blends showed higher impact strength compared to binary blends. Especially, at −30 °C, brittle-ductile transition was observed between 20 and 30 wt% EPDM. Subsurface morphology was also analyzed, and the relationship between the impact strength and the stress whitening zone was investigated. Scanning electron microscopy observation of impact fractured surfaces was conducted, and overall morphology was analyzed with respect to HDPE addition and testing temperature change.

Dynamic mechanical properties of polypropylene-g-maleic anhydride and ethylene-propylene-diene terpolymer blends: Effect of blend preparation methods

In this work, we attempted two different ways of processing to improve interfacial adhesion of polypropylene (PP) and ethylene–propylene–diene terpolymer (EPDM) by introducing maleic anhydride (MAH); In one way, the in situ grafting and dynamic vulcanization (ISGV) were performed simultaneously from PP and EPDM with MAH in the presence of dicumyl peroxide (DCP) in an intensive mixer. In another way, PP was first grafted with MAH and then the PP-g-MAH was blended with EPDM in the intensive mixer in the presence of DCP by the dynamic vulcanization (DV). It was found that the glass transition temperatures (Tgs) of both PP and EPDM phases were shifted to higher temperature as the EPDM content increased for the blends prepared by both IGSV and DV methods, mainly due to the crosslinking of EPDM. The higher Tgs and larger storage moduli were observed for the blends prepared by the ISGV method than those prepared by the DV method, while the morphology showed that the size reduction of dispersed particles in latter blends was larger than that of the former blends. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2777–2784, 2000

Impact toughening behaviour of quaternary PP/HDPE/EPDM/EP blends

Abstract Quaternary blends of polypropylene (PP), high-density polyethylene (HDPE), ethylene–propylene diene terpolymer (EPDM) and ethylene–propylene block copolymer (EP) were prepared in a twin-screw extruder followed by injection moulding. Izod impact tests were used to determine the impact behaviour of the blends. The results showed that the quaternary blends with EPDM content ≥30 wt% exhibit superior impact strengths at 25 and −30°C. This was due to shear yielding of the matrix in the stress whitening zone of the blends containing 30 wt% EPDM. However, Izod impact tests showed that the impact energies of the blends with 25 wt% EPDM content are dependent on the HDPE concentration at 25°C. With a higher concentration of HDPE (≥15 wt%), the impact strengths at 25°C were comparable to those of the blends containing EPDM content ≥30 wt%. The blends with EPDM ≤25 wt% exhibited low-impact toughness at −30°C as featureless fracture surface and cavitation around the rubber particles were observed in the induction zone ahead of the notch tip. The measured impact strengths generally correlated well with the SEM surface morphologies.