Ethylene Propylene Diene Copolymer Research Articles

The effect of pyrolytic carbon black prepared from junked tires on the properties of ethylene-propylene-diene copolymers (EPDM)

Pyrolytic carbon black (PCB) made from used tires was used in ethylene-propylene-diene copolymers (EPDM). The microstructure of PCB was characterized by scanning electron microscopy (SEM). PCB was compounded with EPDM to prepare EPDM vulcanizates. The effects of PCB on the processing properties of EPDM compounds and the mechanical properties of vulcanizates were investigated and compared with other traditional fillers such as semi-reinforcing furnace black (N774), light calcium carbonate (CaCO3) and thermal black (N990). At the same time, the rheological behavior of EPDM compounds filled with different fillers was characterized by capillary rheometrics. The SEM photos showed that the particle shape was quiet different from that of CaCO3 and N990, it was similar to that of N774. The primary particle size was smaller than that of N774, but the aggregate size of PCB was larger than that of N774. The effect of PCB on the pro- cessing properties of EPDM compounds was similar to that of other fillers. Among the four fillers, PCB imparted EPDM compounds with higher Mooney viscosity. With the increase of filler content, the scorch time and optimum curing time of EPDM compounds changed little. The reinforcing effect of PCB was similar to that of N990, but inferior to that of N774. With the increase of PCB content, tensile strength, tear strength, and modulus at 100% elongation of EPDM vulcanizates increased significantly. When EPDM was filled with 50 phr PCB, the tear strength of EPDM vulcanizates increased by 3 times, compared with that of EPDM gum vulcanizates. The appearance of EPDM extrudate filled with PCB was coarser than that of other fillers.

Structure and Mechanical Properties of PP/EPDM/Attapulgite Ternary Blends

Polypropylene(PP)/ethylene-propylene-diene copolymer (EPDM)/fibrillar silicate attapulgite (AT) ternary blends were first prepared via the two-step melt blending process, by which the AT was blended with EPDM prior to compound with PP. Structure and mechanical properties of the blends were investigated. According to the analysis of TEM and DMA test, it was concluded that as for PP/EPDM/AT ternary blends, the typical “sea-island” morphology was observed, and the morphology of encapsulated structure like sandbag was formed in PP matrix besides neat EPDM dispersion domain, where EPDM encapsulated fibrillar silicate AT. The most-odds diameter (Dm), the number-average diameter (Dn) and the weight-average diameter (Dw) of dispersed particles decreased with increasing EPDM. PP/EPDM/AT ternary blends showed higher yield strength and dynamic modulus than the corresponding PP/EPDM binary systems due to the reinforcement of AT. PP/EPDM/AT ternary blend (100/20/5) possessed the balanced yield strength (21.9 MPa) and impact strength (47.7 kJ·m−2), relative to 23.0 MPa and 9.4 kJ·m−2 of PP. The micromechanical deformation process-mainly debonding of dispersed particles and shear yielding was mainly responsible for impact resistance of the ternary blends.

Properties of dynamically vulcanized ethylene–propylene–diene copolymer/polypropylene blends

AbstractIn this study, vulcanized thermoplastic elastomers were produced through the formation of crosslinks with peroxide for different ratios of ethylene–propylene–diene copolymer to polypropylene. Mixing was performed with a twin‐screw extruder. Afterward, the yield, tensile strength, elastic modulus, elongation, Izod impact strength, hardness, melt flow index, Vicat softening point, heat deflection temperature, and density of the crosslinks were determined. The thermal transition temperatures and microstructure were determined with differential scanning calorimetry and scanning electron microscopy, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3895–3902, 2007

About morphology in ethylene–propylene(-diene) copolymers-based latexes

Coatings and engineering plastics often require high impact strength. This property can be achieved with tougheners. For the present paper, core-shell impact modifiers were synthesized using ethylene–propylene copolymers (EPM), ethylene–propylene-diene copolymers (EPDM) or a mixture of both types (EP(D)M) as core material, as well as poly(methyl methacrylate) (PMMA) as shell material. EP(D)M-based polymers were dispersed in water using an Ultra-Turrax ® and a high pressure homogenizer. The prepared artificial latexes were used, either without further treatment or after crosslinking, as seed latexes in the emulsion polymerization of methyl methacrylate (MMA). The free radical seeded emulsion polymerization of MMA was investigated in the presence of an oil-soluble initiator, i.e. cumene hydroperoxide (CHP), combined with a redox system, i.e. sodium formaldehyde sulfoxylate hydrate (SFS), disodium salt of ethylenediamine tetra-acetic acid (EDTA), iron (II) sulfate heptahydrate (FeSO 4). This initiation system promotes polymerization of MMA near the surface of the seed particles, partially suppressing homogeneous secondary nucleation and polymerization in the aqueous phase. Kinetic and thermodynamic considerations were used to predict the particle morphology. The monomer type, the monomer-to-rubber ratio, the monomer feed type, and crosslinking of the seed latex particles were investigated, to optimize the polymerization kinetics and the properties of the resulting dispersions. The particle morphology was determined by cryo-transmission electron microscopy (cryo-TEM). Monomer-flooded conditions led to the formation of inverted core-shell particles, whereas starved–feed MMA or MMA/styrene mixtures gave rise to partially engulfed structures, i.e. snowman-like. Crosslinking of the EP(D)M seed particles was found to be required to provide the desired core-shell structures. Finally, the obtained core-shell structured particles were used to toughen a PMMA matrix. The tensile properties of the modified PMMA matrix were investigated. The micro-morphology of modified PMMA was studied by scanning electron microscopy (SEM). Tensile tests as well as TEM and SEM analyses demonstrated that the main mechanism of deformation operating in the EP(D)M-toughened PMMA matrix is shear yielding, accompanied by debonding and cavitation processes.

Compatibility effect on the thermal degradation behaviour of polypropylene blends with polyamide 6, ethylene propylene diene copolymer and polyurethane

The morphology and thermal behaviour of polypropylene/polyamide 6 (PP/PA6), polypropylene/copolymer ethylene propylene diene (PP/PEBAX) and polypropylene/rigid polyurethane (PP/PUR) blends compatibilised with polypropylene- graft-maleic anhydride (PP- g-MA) were studied using scanning electron microscopy and thermogravimetric analyses. The study focuses on the influence of different blends obtained by mixing a thermoplastic, thermoplastic elastomer or thermoset with PP, compatibilised with PP- g-MA. The compatibilising effect of PP- g-MA in an immiscible PP/PA6 blend induces a homogeneous dispersion due to interfacial adhesion. For the PP/PEBAX and PP/PUR binary blends studied slight changes in the morphology were observed with a continuous phase but the PEBAX or PUR domains remained in the PP matrix. The deconvolution of the TGA curve permitted an evaluation of the decomposition stage of the undiluted and blend systems. Thermal stability is slightly influenced by the position of the maximum decomposition rate temperature of the first derivative thermogravimetric curve (DTG). However, the DTG curve profile remains consistent. The activation energy of undiluted PP was in the range of 162–169 kJ mol −1 determined by the Ozawa method. The stabilized activation energy value for all blends studied above a 0.4 weight-loss fraction is discussed.

About crosslinking of low molecular weight ethylene-propylene(-diene) copolymer-based artificial latices

Crosslinking of artificial latices based on ethylene–propylene copolymers (EPM) and/or ethylene–propylene–diene copolymers (EPDM) has not thoroughly been studied yet. Moreover, crosslinking of EPM and/or EPDM particles is a prerequisite for the formation of a shell using seeded emulsion polymerization of, for example, methyl methacrylate (MMA), as described elsewhere. Therefore, the aim of this article is to improve the general understanding of the chemistry involved in the crosslinking process. This work especially emphasizes the influence of the initiation method, that is, a peroxide or a pulsed electron-beam, on crosslinking efficiency. All crosslinking efficiencies were obtained after extraction of the soluble polymer by tetrahydrofuran. The incorporation of the coagent, that is, divinylbenzene, into the EPM/EPDM phase was studied on a microscopic level by solid-state 13C and 1H nuclear magnetic resonance (NMR). Crosslinking of a low molecular weight EPM/EPDM latex requires the presence of a coagent, for example, divinylbenzene, 1,6-hexanediol diacrylate, or poly(1,2-butadiene). The efficiency of crosslinking initiated by a pulsed electron-beam was improved to a great extent by the presence, in the aqueous phase, of potassium nitrosodisulfonate, also referred to as Fremy salt. Matrix Assisted Laser Desorption/Ionization–Time of Flight–Mass Spectrometry (MALDI-TOF-MS) was used to determine the influence of electron-beam irradiation on the chemical stability of surfactants. It was demonstrated that sodium dodecyl benzene sulfonate (SDBS) is not degraded by the irradiation, and is therefore the surfactant of choice for the stabilization of EPM/EPDM-based latices subjected to electron-beam irradiation. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3600–3615, 2005

New materials from degraded styrene-acrylonitrile and ethylene-propylene-diene copolymers

Abstract Polymer blends of styrene-acrylonitrile (SAN) and ethylene-propylenediene copolymer (EPDM) were prepared by casting films from chloroform solution. Their compositions were 95/5, 90/10 and 80/20, respectively. To simulate ageing, SAN/EPDM blends were degraded at 140°C for several different time intervals and the degree of degradation was followed by IR spectroscopy and by determination of molar masses. To recover thermally degraded SAN/EPDM blends, in situ polymerization by addition of styrene monomer was applied. Characterization of SAN and EPDM, graft copolymer and gel was carried out in order to reveal the polymerization process. Extractions of the polymers were made using solvents in a Soxhlet equipment: SAN in a mixture of acetone/ methanol, EPDM in hexane, graft copolymer in tetrahydrofuran, while the remaining part was considered as gel. Identification of extracted polymers has been conducted by IR spectroscopy. The presence of graft copolymer in the polymerization mixture proved the grafting reaction of polymer radicals. The highest content of graft copolymer was obtained for SAN/EPDM polymer blends that were exposed to thermal treatment for the longest time interval of 90 h.

Effect of EPDM-MAH compatibilizer on the mechanical properties and morphology of nylon 11/PE blends

This study focused on the effect of the maleated ethylene–propylene–diene copolymer (EPDM-MAH) as a compatibilizer on the mechanical properties and morphology of nylon 11/polyethylene (PE) blends. Although the tensile strength and elongation at break of compatibilized nylon 11/PE deviated slightly from the pure nylon 11, the Izod impact strength at room temperature and at low temperature was improved markedly by the addition of 3% compatibilizer. The SEM micrographs of fractured surfaces demonstrated further the enhancement of compatibility between nylon and PE by addition of a reactive compatibilizer.

Production of colloidally stable latices from low molecular weight ethylene–propylene–diene copolymers

The best impact modifiers for coatings and engineering plastics include fixed morphology core-shell particles. For the present work, ethylene–propylene copolymers (EPM) and ethylene–propylene–diene copolymers (EPDM) were chosen, for their good resistance to stringent conditions, like UV-irradiation or high temperatures, to prepare the core of the desired particles. The solution-emulsification technique was used to produce artificial latices based on low molecular weight EPM and EPDM materials. Conventional emulsification techniques as well as ‘miniemulsification’ methods have been investigated. In both cases, a larger volume of polymer is reduced into smaller sub-units using the mechanical energy of comminution techniques, i.e. an Ultra-Turrax ® and a homogenizer operating at a pressure of 300 bar and with a shear rate of approximately 3.2×10 7 s −1. The difference between conventional emulsification and miniemulsification resides in the stabilizing system. For the conventional emulsification method, an equimolar mixture of anionic (sodium dodecyl benzene sulfonate, SDBS) and nonionic (polyoxyethylene (100) stearyl ether, Brij 700) surfactants was found to be the optimal surfactant system. For the miniemulsification method, a combination of SDBS as surfactant and hexadecane or cetyl alcohol as costabilizer was the most suitable system. Both conventional emulsification and miniemulsification lead to latices with monomodal particle size distributions and volume-average diameters ranging from 300 to 400 nm, determined with light scattering techniques. The low molecular weight elastomers, exhibiting viscosities lower than 1 Pa s at 20 °C, were easily emulsified without addition of organic solvent.

Blendas de poliamida 6/elastômero: propriedades e influência da adição de agente compatibilizante

Neste trabalho foram estudadas as propriedades micro e macroscópicas de misturas físicas binárias de poliamida 6 [PA6] com copolímero poli(etileno-co-propileno-co-dieno) [EPDM] e em presença de pequenas quantidades de EPDM ou EPM enxertados com anidrido maleico, atuando como agentes compatibilizantes. Os componentes puros (poliamida 6 e EPDM) e as blendas poliméricas em diferentes composições foram analisados por calorimetria diferencial de varredura (DSC) e espectroscopia de infravermelho (FTIR). Os resultados indicaram a imiscibilidade dos componentes da mistura em toda a faixa de composição estudada. A utilização das técnicas de análise elementar, microscopia eletrônica de varredura e propriedades mecânicas permitiu avaliar a homogeneidade da mistura, a redução do tamanho dos domínios do elastômero e o aumento da força de impacto da matriz de PA6 com a adição do agente compatibilizante à mistura binária de PA6/EPDM.

Influence of coalescence and interfacial tension on the morphology of PP/HDPE compatibilized blends

In this paper, the compatibilization of polypropylene (PP)/high-density polyethylene (HDPE) blend was studied through morphological and interfacial tension analysis. Three types of compatibilizers were tested: ethylene–propylene–diene copolymer (EPDM), ethylene–vinylacetate copolymer (EVA) and styrene–ethylene/butylene–styrene triblock copolymer (SEBS). The morphology of the blends was studied by scanning electron microscopy. The interfacial tension between the components of the blends was evaluated using small amplitude oscillatory shear analysis. Emulsion curves relating the average radius of the dispersed phase and the interfacial tension to the compatibilizer concentration added to the blend were obtained. It was shown that EPDM was more efficient as an emulsifier for PP/HDPE blend than EVA or SEBS. The relative role of interfacial tension reduction and coalescence reduction to particle size reduction was also addressed. It was observed that the role of coalescence reduction is small, mainly for PP/HDPE (90/10) blends compatibilized by EPDM, EVA or SEBS. The results indicated that the role of coalescence reduction to particle size reduction is lower for blends for which interfacial tension between its components is low at compatibilizer saturation.

Effect of oil and cured agent content on the structure and properties of thermoplastic vulcanizates

The effect of oil and curing agent content on the mechanical behavior of thermoplastic vulcanizates, based on a polypropylene (PP) and ethylene-propylene-diene copolymer (EPDM), was investigated. Mechanical properties such as Young's modulus, stress at 100% elongation and ultimate stress were investigated as a function of blends' composition and phase morphology. Experimental studies show that the Young's modulus of the vulcanizates depends on both PP/EPDM ratio and oil content in the blends; both ultimate strength and stress at 100% elongation increase with curing agent content.

The effect of addition of different elastomers upon the crystalline nature of PP

AbstractThermal and morphological studies have been performed on polymer blends based on ethylene–octene copolymer (PEE)/PP and ethylene–propylene–diene copolymer (EPDM)/PP. The thermal and morphological behavior of PEE, EPDM, PEE/PP, and EPDM/PP systems were analyzed by differential scanning calorimetry (DSC) and polarizing light microscopy, respectively. It was observed that the behaviors of crystallization kinetics of PEE/PP and EPDM/PP blends were similar. It was also observed that addition up to 10–20% (w/w) of elastomers resulted in increasing of spherulite size. The heat of fusion (ΔHf) and crystallinity degree of PEE/PP and EPDM/PP systems decreased when the elastomer contents were increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3530–3537, 2001

Recycling of commingled plastics waste containing polypropylene, polyethylene, and paper

AbstractPolymer waste recycling is a major technical problem, because large amounts of synthetic polymers are produced every day and polymeric wastes are gathered from municipal solid wastes. There are a few polyolefins, such as polyethylene (PE) and polypropylene (PP) with huge amounts of paper in the waste materials. In order to recycle the commingled plastics waste that contains paper, hydrolytic treatment is needed prior to conventional processing. In this project, the optimum conditions of hydrolytic treatment of paper and the mechanical properties and morphological state of different compositions of PP high‐density PE (HDPE) blends with paper were studied. Ethylene‐propylene‐diene copolymer (EPDM) was added to improve the mechanical properties of blends. The results show that the hydrolytic treatment of paper improves the mechanical properties, such as the tensile strength and modulus of the PP/HDPE/paper composites relative to the untreated samples, and up to 30% paper can be added to commingled PP and HDPE blends. The EPDM was used as an impact modifier. The plastics waste containing paper can be used in applications such as artificial wood. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2573–2577, 2001

Electron spin resonance study on chemical crosslinking reaction mechanisms of polyethylene using a chemical agent. V. Comparison with polypropylene and ethylene‐propylene copolymer

We studied the chemical reaction process of polypropylene (PP), ethylene-propylene copolymer (EPM), and ethylene-propylene-diene copolymer (EPDM) crosslinking induced by dicumyl peroxide (DCP) using electron spin resonance (ESR). Free radicals appeared at an elevated temperature of around 120 °C and the behavior and kinetics of the reaction process were observed at 180 °C. The radical species detected in PP were alkyl type radicals, formed by the abstraction of hydrogen atoms from the tertiary carbon of polymer chains. For EPDM containing a diene component, the radicals were trapped at double bonds in this diene component to form allyl radicals. The resolutions of these spectra were extremely clear; hence, isotropic spectra of these polymer radicals were obtained. We measured the ESR at high temperatures and confirmed that the process of crosslinking induced by DCP was a free radical reaction. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3383–3389, 2000

Thermomechanical and adhesive properties of radiation-modified polymer composites for thermosetting products

Gamma-irradiated blends of polyethylene (PE) with ethylene-propylene-diene copolymer (EPDM) and a thermotropic liquid-crystalline polymer (LCP) are investigated at absorbed radiation doses not exceeding 150 kGy (10 kGy=1 Mrad). The temperature dependences of elastic moduli, tension diagrams at a temperature above the melting point of the crystalline phase of PE, and long-term strain recovery curves for oriented test specimens are presented. The kinetics of thermal relaxation and shrinkage stresses in previously oriented composite specimens upon their heating and cooling is investigated. Data on the influence of LCP additions on the adhesive interaction of the compositions with steel are obtained. The peculiarities of thermomechanical and adhesion properties of these composites are discussed taking into account the morphologic and calorimetric data obtained.

Electron spin resonance study on chemical crosslinking reaction mechanisms of polyethylene using a chemical agent. V. Comparison with polypropylene and ethylene-propylene copolymer

We studied the chemical reaction process of polypropylene (PP), ethylene-propylene copolymer (EPM), and ethylene-propylene-diene copolymer (EPDM) crosslinking induced by dicumyl peroxide (DCP) using electron spin resonance (ESR). Free radicals appeared at an elevated temperature of around 120 °C and the behavior and kinetics of the reaction process were observed at 180 °C. The radical species detected in PP were alkyl type radicals, formed by the abstraction of hydrogen atoms from the tertiary carbon of polymer chains. For EPDM containing a diene component, the radicals were trapped at double bonds in this diene component to form allyl radicals. The resolutions of these spectra were extremely clear; hence, isotropic spectra of these polymer radicals were obtained. We measured the ESR at high temperatures and confirmed that the process of crosslinking induced by DCP was a free radical reaction. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3383–3389, 2000

Effect of Long-chain Branching and Microgels in the Viscoelastic Behavior of Ethylene—Propylene—Diene Copolymers

Ethylene—propylene-diene (EPDM) terpolymers with different amounts of microgel and long-chain branching have been characterized by dynamic mechanical experiments. Low frequency measurements were found particularly useful for revealing differences in viscoelastic properties of the samples Loss factor values were of limited use, as they are influenced by sample molecular weights. Modified Cole—Cole plots were verified to be molecular weight independent, and could therefore be employed to detect molecular architecture variations. It was determined that long-chain branching and microgels are almost entirely localized in the higher molecular weight fractions of the investigated EPDM samples.

Temperature and concentration dependence of diffusion coefficients in ethylene-propylene-diene copolymers

Self-diffusion and partition coefficients were measured for two commercial ethylene–propylene-diene copolymers (EPDM) and five solvents at infinite dilution using inverse gas chromatography. Mutual diffusion coefficients for solvents in EPDM also were measured for finite concentration using gravimetric sorption for three of the solvents. From the inverse gas chromatography experimental values for self-diffusion coefficients were obtained. Free-volume parameters were obtained through regression of the self-diffusion coefficient as a function of temperature. Mutual diffusion coefficients as a function of concentration were predicted using free volume theory and compared with experimental data obtained using gravimetric sorption. © 1998 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 36: 1713–1719, 1998

Structure and properties of rubbertoughened polyethylene-based blends

Abstract The preparation, thermal behaviour, mechanical properties and morphology of a family of binary blends composed of components each containing ionic functionalities are examined. One component is a semicrystalline copolymer, metal-neutralized ethylene-methacrylate (M-EMA), and the other an elastomeric component, metal-neutralized sulphonated ethylene-propylene diene copolymer (M-SEPDM). These polymeric materials contain low levels of ionic groups (≤ 10 mol%) which are capable of coulombically associating together into microphase-separated regions. These regions contain nonstoichiometric levels of ionic groups. A general characteristic of these blend systems is that the mechanical properties and morphology are directly influenced by the specific composition ratio of rubber to semicrystalline component. Without the associating units on one (or both) of the components, the resulting blends have grossly phase-separated components. The interfacial adhesion is weak, as indicated by poor tensile properties. The inter-relationship between structure and mechanical properties is discussed in terms of changes in the initial spherulitic morphology of the M-EMA component with the addition of increasing levels of the coulombically associating elastomeric component, M-SEPDM.