Propylene Diene Terpolymer Blends Research Articles

Mullins Effect and Its Reversibility of Thermoplastic Vulcanizates Based on Polypropylene/Ethylene–Propylene–Diene Terpolymer Blends Under Compression Mode

ABSTRACTMullins effect and its reversibility of ethylene–propylene–diene terpolymer/carbon black vulcanizate and polypropylene/ethylene–propylene–diene terpolymer thermoplastic vulcanizate under compression mode were investigated systematically. Morphology studies showed that sphere-like ethylene–propylene–diene terpolymer particles were dispersed evenly in the etched thermoplastic vulcanizate surface with diameter of 5–7 µm. The results showed that thermoplastic vulcanizate demonstrated characteristic features (hysteresis of energy, residual deformation accumulation, stress softening) of Mullins effect. Compared with that of ethylene–propylene–diene terpolymer/carbon black vulcanizate, the polypropylene/ethylene–propylene–diene terpolymer thermoplastic vulcanizate had much higher stress and its stress softening phenomenon was more obvious. The reversibility of Mullins effect showed a temperature-dependent feature and was enhanced with increasing temperature.

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.

Transport properties of high-density polyethylene/ethylene propylene diene terpolymer blends

Polymer blends based on high-density polyethylene and ethylene propylene diene terpolymer rubber (EPDM) were prepared. The sorption and diffusion of four aliphatic hydrocarbons through the blends were studied in the temperature range of 28–58 °C. Sulfur, dicumyl peroxide (DCP), and a mixture of sulfur and DCP (mixed) were used as cross-linking agents for the blends. Of the three systems, the peroxide vulcanized blends were found to exhibit the lowest penetrant uptake. This has been explained based on the higher rigidity of the –C–C– networks than the polysulfide linkages. The aliphatic liquid penetration through the matrix increased with increase in the EPDM content in the blend. The experimental observations were correlated with the morphology of the blends. Diffusion and permeation coefficients were calculated from the sorption data. A slight deviation from the Fickian trend was observed for the mechanism of transport with an increase in EPDM in the blends. The molar mass between cross-links and thermodynamic parameters of sorption was determined from the swelling data. The experimental observations were compared with various theoretical models.

Dynamic vulcanization of polyethylene‐based thermoplastic elastomer blends

AbstractIn this investigation, the effects of blending with ethylene–propylene–diene terpolymer and subsequent dynamic curing with sulfur on the macromolecular structure and properties of pure low‐density polyethylene and high‐density polyethylene were studied. The crosslinking efficiency of polyethylene‐based ethylene–propylene–diene terpolymer blends upon dynamic curing was assessed with torque and gel content measurements. The curing of dispersed ethylene–propylene–diene terpolymer in a polyethylene matrix improved both the mechanical and thermomechanical properties as a result of the formation of a crosslink structure in the rubber phase. In view of the electrical applications of this cured blend material, the volume resistivity was measured. The thermal stability of vulcanized polyethylene/ethylene–propylene–diene terpolymer blends was found to be superior to that of unvulcanized blends. In scanning electron microscopy analysis, good interface bonding between the polyethylene matrix and dispersed ethylene–propylene–diene terpolymer was observed for the cured blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Evidences of solvent‐induced miscibility in polychloroprene‐co‐ethylene‐propene diene terpolymer blends

AbstractSolvent dependent changes in the compatibility behavior of Polychloroprene/Ethylene–propylene–diene terpolymer blends (CR/EPDM) have been investigated using dilute solution viscometry and solvent permeability analysis. To predict the compatibility of rubber blends of different compositions in solvents of different cohesive energy densities, Huggins interaction parameter (ΔB), hydrodynamic interaction (Δη) and Sun's parameter (α) were evaluated from the analysis of the specific and reduced viscosity data of two and three‐component polymer solutions. Miscibility criteria were not satisfied for CR/EPDM blends over the entire composition range in toluene, xylene, and carbon tetrachloride (CCl4), however, a narrow miscibility domain was observed in chloroform (CHCl3) for CR/EPDM/CHCl3 system. These results were further corroborated with the analysis of heat of mixing (ΔHm) and polymer–polymer interaction parameter (χ12), for all rubber blend compositions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Mechanical, thermal, and morphological characteristics of compatibilized and dynamically vulcanized polyoxymethylene/ethylene propylene diene terpolymer blends

AbstractDynamically vulcanized blends of polyoxymethylene (POM) and ethylene propylene diene terpolymer (EPDM) with and without compatibilizer were prepared by melt mixing in a twin screw extruder. Maleic anhydride (MAH) grafted EPDM (EPDM‐g‐MAH) has been used as a compatibilizer. Dicumyl peroxide was used for vulcanizing the elastomer phase in the blends. Mechanical, dynamical mechanical, thermal, and morphological properties of the blend systems have been investigated as a function of blend composition and compatibilizer content. The impact strength of both dynamically vulcanized blends and compatibilized/dynamically vulcanized blends increases with increase in elastomer content with decrease in tensile strength. Dynamic mechanical analysis shows decrease in tanδ values as the elastomer and compatibilizer content increased. Thermograms obtained from differential scanning calorimetric studies reveal that compatibilized blends have lower Tm values compared to dynamically vulcanized blends, which confirms strong interaction between the plastic and elastomer phase. Scanning electron microscopic observations on impact fractured surface indicate reduction in particle size of elastomer phase and its high level of dispersion in the POM matrix. In the case of compatibilized blends high degree of interaction between the component polymers has been observed. POLYM. ENG. SCI., 47:934–942, 2007. © 2007 Society of Plastics Engineers

Viscosities of ethylene–propylene–diene terpolymer blends in oil

AbstractViscosities were obtained on oil solutions of two ethylene–propylene–diene terpolymers (EPDMs) and their blends. For the amorphous terpolymer with 59 mol% ethylene, intrinsic viscosities were constant between–10 and 40°C. The viscosities decreased rapidly at low temperature for blends of this material with as little as 20 wt % of a slightly crystalline EPDM with 79 mol% ethylene. Dynamic viscosity measurements on 1.0% solutions of blends likewise gave considerably smaller values at low temperature than measurements on an amorphous EPDM of similar molecular weight. The data are in agreement with the view that longer ethylene sequences that crystallize in the bulk polymer can organize in oil into ordered domains that interfere less with flow than the disordered amorphous polymer regions. © 1993 John Wiley & Sons, Inc.

Effect of cross-linking on the crystallization and fusion behaviour of polyethylene-ethylene propylene diene terpolymer blends

The effect of blend ratio and cross-linking in ethylene propylene diene terpolymer (EPDM) and polyethylene (PE) blends on the crystallization and fusion processes of PE were studied. The cross-linking was varied by varying the level of dicumyl peroxide (DCP) from 0.5 to 5 parts. The melting point, percentage crystallinity, heat of fusion and entropy of fusion all decrease with increasing EPDM content in the blend composition. All these properties are further reduced on cross-linking and the extent of reduction depends on the amount of DCP used and the blend composition. A relation between the melting point reduction and the high-temperature modulus was developed in order to predict the properties and the effect of cross-linking on the crystallization behaviour of the blend systems.