Ethylene Propylene Diene Elastomer Research Articles

Effect of the Compatibiliser on the Morphology and Properties of Dynamically Cured PP/EPDM/Epoxy Blends

Dynamic vulcanisation was successfully applied to epoxy resin reinforced polypropylene (PP)/ethylene-propylene diene elastomer (EPDM) blends, and the effects of different compatibilisers on the morphology and properties of dynamically cured PP/EPDM/epoxy blends were studied. The results show that dynamically cured PP/EPDM/epoxy blends compatibilised with maleic anhydride-grafted polypropylene (MAH-g-PP) have a three-phase structure consisting of EPDM and epoxy particles dispersed in the PP continuous phase, and these blends had improved tensile strength and flexural modulus. While using maleic anhydride-grafted EPDM (MAH-g-EPDM) as a compatibiliser, the structure of the core-shell complex phase and the PP continuous phase showed that epoxy particles could be embedded in MAH-g-EPDM in the blends, and gave rise to an increase in impact strength, while retaining a certain strength and modulus. DSC analysis showed that the epoxy particles in the blends compatibilised with MAH-g-PP were more efficient nucleating agents for PP than they were in the blends compatibilised with MAH-g-EPDM.

Cross-linking assessment after accelerated ageing of ethylene propylene diene monomer rubber

The ageing of filled and cross-linked ethylene propylene diene elastomer (EPDM) has been studied under accelerated UV irradiation ( λ ≥ 290 nm) at 60 °C, thermal ageing at 100 °C and in nitric acid vapours for different time intervals. Hardness measurements were performed. DSC-thermoporosimetry was used to estimate the mesh size distribution and cross-linking densities for each ageing. The development of functional groups was monitored by ATR spectroscopy. An increase in oxidation with exposure time after the different types of ageing was observed. The thermal stability of EPDM was assessed by TGA and evolved volatile gases were identified using FTIR spectroscopy.

Microstructure, Interfacial Interactions, and Rheological Properties of PC/AES/Montmorillonite Composites

Polycarbonate (PC) and acrylonitrile–EPDM (ethylene/propylene/diene elastomer)–styrene ter‐polymer (AES) blends and PC/AES/organically modified montmorillonite (OMMT) composites were prepared at 20%, 40%, 50% by weight of AES and 3% by weight of OMMT. The microstructure, interfacial interactions, and rheological properties of the PC/AES blends and PC/AES/OMMT composites were studied systematically. X‐ray diffractometer (XRD) results reveal that the AES is easier to intercalate into OMMT than PC, and the content of AES has a little effect on the interlayer distance of OMMT. Wetting coefficient calculation indicates that OMMT distributes primarily at the interface of the polymer blend. Field emission scanning electron microscope (FE‐SEM) observation indicates that the phase morphology of PC/AES blends and PC/AES/OMMT composites is not influenced by the OMMT. However, linear rheological properties suggest that the addition of OMMT has a great effect on the linear rheological property.

Rheological Properties and Morphology of PC/AES Blends

Blends of polycarbonate (PC) and acrylonitrile–EPDM (ethylene/propylene/diene elastomer)–styrene terpolymer (AES) were prepared at 20%, 30%, 40%, 50%, and 80% by weight of AES. The rheological properties and morphology of the PC, AES, and their blends were studied systematically. The strain sweep results show that the linear viscoelastic region of the AES is far less than that of PC. With the addition of AES, the linear viscoelastic regions become shorter gradually. The dynamic frequency sweep measurements indicate that the dependences of the complex viscosity on frequency for PC and AES are very different. With the increase of AES content, the complex viscosities of blends exhibit a more significant shear thinning behavior. All the samples, except PC, display a distinct nonterminal behavior at low frequencies. The level of the plateau depends on the volume fraction of the rubber phase. PC, AES, and PC/AES blends obey the Cox–Merz rule generally. The blends, which have similar morphology, show similar rheological properties.

Molecular and Supermolecular Structure of Different Grades of Ethylene–Propylene–Diene Elastomers

Molecular and Supermolecular Structure of Different Grades of Ethylene–Propylene–Diene Elastomers

Plasma-polymerized perfluoro(methylcyclohexane) coating on ethylene propylene diene elastomer surface: Effect of plasma processing condition on the deposition kinetics, morphology and surface energy of the film

Plasma polymerization of perfluoro (methylcyclohexane) was carried out under cold plasma process operated at 13.56 MHz to deposit pore-free, uniform, ultra-thin film on an ethylene propylene diene terpolymer (EPDM) substrate in a view to modify the surface characteristics. The plasma fluoropolymeric films were formed at different plasma treatment times (from 20 s to 16 min), applied powers (20 to 100 W) and precursor flow rates to produce high quality films in a controllable yet tunable fashion. Scanning electron microscopy was employed successfully to characterize the evolution of the morphological feature in the film and also to determine the thickness of the coating. The surface energy of the film was determined by sessile drop method using different solvents as probe liquids. It is observed that a pore-free homogeneous plasma polymer thin film is formed within 20 s of treatment time, however, the morphology of the film depends on the plasma processing conditions, such as plasma power, precursor flow rate and deposition time. With increased time and power at a constant flow rate, the morphology of the film progressively changes from flat smooth to globular and rough. The kinetics and activation energy of the plasma polymer film deposition process were also estimated. The surface energy of the EPDM substrate decreased dramatically with plasma coating, however, it appears to be independent of the treatment time.

Radiochemical ageing of ethylene–propylene–diene elastomers. 4. Evaluation of some anti-oxidants

The preceding papers of this series were devoted to the identification and quantification of the main chemical changes resulting from the radiochemical ageing of EPDM (77.9% ethylene, 21.4% propylene, 0.7% diene) and EPR (76.6% ethylene, 23.4% propylene) films irradiated under oxygen atmosphere using 60Co γ-rays. It was shown that two processes are involved in the EPDM radio-oxidation. The random γ-radiolysis of the polymer provides a constant source of macro-alkyl radicals that are likely to initiate a selective oxidation of the polymer through free-radicals reactions involving the abstraction of labile hydrogen atoms. In the present paper, infrared spectroscopy has been used to study the γ-degradation of EPDM cross-linked with dicumyl peroxide and/or stabilised with two types of anti-oxidants (hindered phenol or amine-type). The results show that the anti-oxidants are not efficient in preventing oxidation. To understand the lack of efficiency of the stabilisers, the impacts of the various formulations on the rate of degradation of EPDM against chain oxidation involved in thermal and UV ageing were also studied.

A polymer network based on thermoplastic polyurethane and ethylene–propylene–diene elastomer via melt blending: morphology, mechanical properties, and rheology

Blends of thermoplastic polyurethane (TPU) and ethylene–propylene–diene elastomer (EPDM) were prepared via a melt blending, and morphology, mechanical properties, and rheology were studied. Scanning electron microscopy (SEM) micrographs demonstrated that a network of EPDM domain was formed in TPU matrix, and became finer and more perfect with addition of 8 wt% EPDM into TPU. Dynamic mechanical analysis (DMA) and Fourier transformed infrared spectroscopy (FTIR) investigation indicated that EPDM was thermodynamically miscible with the soft segments of TPU and incompatible with the hard segments. The formation of the network was resulted from the competition of compatible and incompatible segments of TPU with EPDM. The tensile strength and elongation at break achieved a significant improvement with addition of EPDM, and obtained the optimum values of 39.21 MPa and 2659%, respectively, when EPDM content was 8 wt%. PEO-g-MA as a compatibilizer was employed to improve the compatibilization between EPDM and the hard segments of EPDM, and consequently, the network became finer and more perfect. The evaluation of rheological properties revealed that the introduction of EPDM into TPU resulted in a reduction of the viscosity at high shear rate and a decrease of the flow activation energy; thus the processability of the blends was improved.

Toughening of poly(2,6-dimethyl-1,4-phenylene oxide)/nylon 6 alloys with functionalized elastomers via reactive compatibilization: morphology, mechanical properties, and rheology

Blends of poly(2,6-dimethyl-1,4-phenylene oxide)/nylon 6 alloys based on ethylene-propylene-diene elastomer (EPDM) grafted with maleic anhydride (MA) (EPDM- g-MA), EPDM grafted with glycidyl methacrylate (EPDM- g-GMA), and styrene-ethylene-butadiene-styrene block copolymer grafted with MA (SEBS- g-MA) were prepared via melt extruction, and morphology, mechanical properties, and rheology were studied. The compatibilizing effects of functionalized elastomers on the PPO/nylon 6 alloys were proved by DSC analysis and confirmed by the significant improvement in the notched Izod impact strength. Toughening was resulted from the smaller particle size and finer dispersion of EPDM in the PPO/nylon 6 matrix as well as a novel network structure of SEBS- g-MA domain in matrix. The notched Izod impact strength of the blends exhibited an optimum value when the extent of MA or GMA graft ratio of EPDM varied, which was an order of magnitude higher than the non-toughened alloys. The morphology revealed that the size of EPDM particles decreased with an increase in graft ratio of MA or GMA onto EPDM. Rheology investigation indicated that the MA or GMA moieties on EPDM reacted with the amine groups of nylon 6, which increased the molecular weight and the degree of branching, and thus resulted in an increase in the viscosity of the blends. This proved the reactive compatibilization between functionalized EPDM and PPO/nylon 6 matrix.

Surface energy and chemistry of ethylene-propylene-diene elastomer (EPDM) treated by plasma immersion ion implantation

Surface energy and chemistry of ethylene-propylene-diene elastomer (EPDM) treated by plasma immersion ion implantation

Blends of polyethyleneterephthalate with EPDM through reactive mixing

Ethylene-propylene-diene elastomer (EPDM), which is grafted with an isocyanate-containing monomer (HI), was blended with polyethyleneterephthalate (PET) and its morphological, thermal, rheological, and mechanical properties were studied. HI was incorporated onto EPDM backbone through a solution graft reaction. When the PET was blended with HI-grafted EPDM (EPDM-g-HI), the morphologies of dispersed phases showed considerable differences in the aspects of particle size and interfacial adhesion compared with those of a PET/EPDM blend. DSC analysis showed that, when blends are cooled slowly, the PET phase in PET/EPDM-g-HI is somewhat amorphous compared with that in the PET/EPDM blend. The increase in complex viscosity, storage modulus and impact strength of PET/EPDM-g-HI blends enabled us to ensure that the compatibility between PET and EPDM improved through functionalization of EPDM with the isocyanate moiety. These results are mainly due to graft PET-EPDM copolymer in situ formed through the chemical reaction between the isocyanate group of EPDM-g-HI and hydroxyl or carboxyl end groups of PET. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 2227–2233, 2000

Relaxation of stress in polypropylene and ethylene-propylene-diene elastomer blend vulcanizates at moderate and high extensions

Measurements were made of the relaxation of the stress of stretched polypropylene (PP) and ethylene–propylene–diene elastomer blend vulcanizates at various strain levels. It was found that PP-blended vulcanizates showed greater relaxation than that of the gum vulcanizate at all extensions. There was a continual increase in the relaxation rate with the 10% PP-blended vulcanizate but an initial sharp decrease and then a flattening tendency with the above 10% PP-blended vulcanizate at an increasing stain level. An interesting observation of the study was that the rate of stress relaxation decreased linearly in two steps in the case of blend vulcanizates above 10% PP at 100% and above strain levels. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2155–2162, 1998

Relaxation of stress in polypropylene and ethylene–propylene–diene elastomer blend vulcanizates at moderate and high extensions

Relaxation of stress in polypropylene and ethylene–propylene–diene elastomer blend vulcanizates at moderate and high extensions

Glass fiber reinforced polypropylene/EPDM blends. II. Mechanical properties and morphology

AbstractTensile and impact properties of the ternary system polypropylene (PP)/ethylene propylene diene elastomer (EPDM)/glass fiber (GF) and the corresponding binary systems PP/EPDM blend and PP/GF composite are studied. Results are presented and analyzed as functions of compositional variables, viz., (i) matrix PP/EPDM blending ratio at constant GF loadings and (ii) GF loading at constant matrix blending ratios for the ternary system and (iii) EPDM content for PP/EPDM binary system and (iv) GF content for the binary system PP/GF, respectively. The role of individual components EPDM and GF in these mechanical properties is discussed and their combined effects are inspected at certain composition ranges. Theoretical analysis of tensile data is presented which reveals the effect of EPDM on the reinforcing effect of GF. Unlike the conventional role of an elastomer, increase of EPDM content in the presence of GF increases the modulus of the ternary system. Impact strength of the ternary system increases with increasing GF content both in the presence and absence of EPDM, showing a distinct minimum at matrix blending ratio PP/EPDM 90/10. Scanning electron micrographs of impact‐fractured surfaces are presented to illustrate the dispersion of the two phases of the polyblend matrix, fiber alignment, and the fiber interface.

Sorption and diffusion of water in ethylene-propylene diene rubber in presence of vulcanization accelerators

The authors have studied the diffusion and sorption patterns of water vapour by the ethylene propylene diene elastomer SKEPT-40 and its composites with vulcanization accelerators in the activity interval of the vapour 0·1 < p/ p s ⩽ 0·85. It is shown that the water sorbed by the polymer is in the matrix in three states: bound, clustered and free. The p/ p s intervals within which the particular states of sorbed water in the elastomer may be realized are determined.

Radiation Curing of Ethylene—Propylene—Diene Elastomers

Abstract A significant reduction of the radiation dose required to cure EPDM elastomers can be obtained by introducing crosslinking monomers into the compounds. Multifunctional acrylates are more efficient than either allylic or pendent-vinyl crosslinking agents. The curing rate is also affected by the nature of the unsaturation in the base polymer. Compounds of EPDM containing 5-ethylidene-2-norbornene are more reactive than those with 1,4-hexadiene. Increasing polymer unsaturation levels above 3 per cent or changes in ethylene—propylene ratios have little effect. Curing rate is dependent, however, on the Mooney viscosity of the elastomer, with higher viscosities yielding faster cures. The addition of extender oils drastically reduces radiation efficiency, which depends on both the nature and the level of the oil. This can be overcome by increasing the monomer content. The physical properties of radiation-cured EPDM compare favorably with those of sulfur-cured EPDM. The radiation-cured EPDM exhibits greatly improved compression set and oil resistance.