Mechanical properties of high‐density polyethylene/scrap rubber powder composites modified with ethylene–propylene–diene terpolymer,dicumyl peroxide,and silicone oil

The effect of ethylene–propylene–diene terpolymer (EPDM), dicumyl peroxide (DCP), and dimethyl silicone oil on the mechanical properties of high‐density polyethylene (HDPE) composites filled with 60 mesh cryogenically scrap rubber powder (SRP) was studied. The addition of 10 wt % EPDM, 0.2 wt % DCP, and 4 wt % dimethyl silicone oil significantly increased both the impact strength and elongation at break of the HDPE/SRP composites. After the modification, the impact strength increased by 160%, and the elongation at break increased by 150% for the composites containing 40 wt % SRP. The impact load–time curves showed that the increase of impact energy for the modified composites was attributed to the increase of the maximum force at yield point and the ductile deformation after yielding. The rheological behavior, dynamic mechanical properties, and morphology observation suggested that an enhanced adhesion between SRP and polymer matrix formed in the modified HDPE/SRP composites. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2020–2027, 2003     

Thermal and mechanical properties of silicon rubber/cis‐polybutadiene rubber/ethylene–propylene–diene monomer blends

Considering the properties of silicon rubber, ethylene–propylene–diene monomer (EPDM), and cis‐polybutadiene rubber (BR), a blend made by a new method was proposed in this article; this blend had thermal resistance and good mechanical properties. The morphology of the blend was studied by SEM, and it was found that the adhesion between the phases of BR, EPDM, and polysiloxanes (silicon rubber) could be enhanced, and the compatibility and covulcanization were good. The influence of the mass ratio of peroxide and silica on the mechanical properties and thermal resistance of the blend was studied. The results showed that the mechanical properties and thermal resistance of the blend were improved when silicon rubber/BR/EPDM was 20/30/50, dicumyl peroxide/sulfur was 2.5/2.5, and the amount of silica was 80 phr. The integral properties of rubber blend had more advantages than did the three rubbers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 4462–4467, 2006     

Effect of borax on the thermal and mechanical properties of ethylene‐propylene‐diene terpolymer rubber‐based heat insulator

The effect of Borax on the mechanical and ablation properties of three different ethylene‐propylene‐diene terpolymer (EPDM) compounds containing 20 phr carbon fiber, 20 phr Kevlar or 10 phr/ 10 phr carbon fiber/ Kevlar was investigated. All formulations contained 30 phr fumed silica powder and 10 phr paraffinic oil. It was found that adding Borax to the composite samples containing carbon fiber or Kevlar fiber or their mixture with an equal ratio can increase the tensile strength, elastic modulus and hardness with a slightly decrease in the elongation at break of the rubber samples. The results of thermogravimetry analysis (TGA) on the various samples showed significant increase in the char yield at 670°C by adding Borax to the rubber compounds. Moreover, ablation resistance of samples was also improved by increasing Borax content. Meanwhile, density and thermal conductivity of the insulator were also reduced up to about 10% when the carbon fiber was replaced with the Borax. The results indicated that composites containing Kevlar have high storage modulus and produce compact and stable char. EPDM rubber composite containing Borax (20 phr), carbon fiber (10 phr), and Kevlar (10 phr) showed thermal and ablative properties comparable with those of the asbestos‐ filled EPDM. The thermal conductivity and ablation rate of the above‐ mentioned sample were 0.287 W/m/K and 0.13 mm/s respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41936.     

Polyamide‐reinforced ethylene–propylene–diene rubber compatibilized with chlorinated polyethylene

Vulcanizates of blends of ethylene–propylene–diene rubber and polyamide copolymers were prepared by reactive compatibilization. A reactive route was employed for compatibilizing these blends with the addition of chlorinated polyethylene (CPE). The influence of the compatibilizers, crosslinking agents, blend compositions, and addition modes of the compatibilizers on the mechanical properties of the blends was investigated. The morphologies of the blends were determined with scanning electron microscopy. The addition of CPE was found to reduce the particle size of the dispersed phase remarkably. The stability of the blends with compatibilizers was measured by high‐temperature thermal aging. The mechanical properties were examined by stress–strain measurements and dynamic mechanical thermal measurements; the addition of polyamide copolymers caused significant improvements in the tensile properties of these blends.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1727–1736, 2003     

Preparation and relaxation dynamics of ethylene–propylene–diene rubber/clay nanocomposites with crosslinking interfacial design

Ethylene–propylene–diene rubber (EPDM)/clay nanocomposites with crosslinking bonding at the interface were fabricated through the intercalation method involving double‐bond functional groups. For comparison, an organoclay modified with an intercalation agent without double bonds was also prepared. X‐ray diffraction indicated that the EPDM intercalated into the galleries of the nanoclay due to crosslinking with the organic intercalation reagent containing double bonds. According to the dielectric relaxation spectra, the segmental relaxation of EPDM was greatly confined, due to the strong filler/polymer interfacial interaction. And a new relaxation appeared at higher temperature and lower frequency than segmental relaxation when the content of clay with double bonds reached 10 phr; the new relaxation is attributed to interfacial relaxation. Whereas the new relaxation did not appear by adding ordinary organoclay, the dynamic mechanical analysis loss peak of EPDM, corresponding to the glass transition, moved to a higher temperature due to covulcanization. The presence of crosslinking in the EPDM/clay nanocomposites can play a significant role in improving their mechanical properties. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45553.     

Preparation and properties of dough‐modeling compound/fly ash/reclaim powder composites

A novel composite was prepared with reclaim powder (RP) matrix, dough‐modeling compound (DMC) reinforcement and fly ash (FA) filler in this article. The compatibility and crosslinking construction of the FA/RP composites were respectively, studied by the polarizing microscope and IR, the optimal formulation and experimental process were determined by measuring the mechanical properties such as shore A hardness, tensile strength, elongation at break, wear resistance and the thermal stability. The results showed that DMC/FA/RP composites exhibited extremely high mechanical and thermal properties when the mass ratio of the DMC/FA/RP composites was 45/25/100, and the cure condition is at 145°C for 30 min under 9 MPa. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Effect of anhydride‐modified ethylene–propylene–diene rubber and ethylene–vinyl acetate copolymers on the compatibilization of nitrile rubber/ethylene–propylene–diene rubber blends

The effects of maleic anhydride modified ethylene–propylene–diene rubber (EPDMMA) and maleic anhydride modified ethylene–vinyl acetate (EVAMA) on the compatibilization of nitrile rubber (NBR)/ethylene–propylene–diene rubber (70:30 w/w) blends vulcanized with a sulfur system were investigated. The presence of EPDMMA and EVAMA resulted in improvements of the tensile properties, whereas no substantial change was detected in the degree of crosslinking. The blend systems were also analyzed with scanning electron microscopy and dynamic mechanical thermal analysis. The presence of EVAMA resulted in a blend with a more homogeneous morphology. The compatibilizing effect of this functional copolymer was also detected with dynamic mechanical analysis. A shift of the glass‐transition temperature of the NBR phase toward lower values was observed. The presence of EPDMMA and EVAMA also increased the thermal stability, as indicated by an improvement in the retention of the mechanical properties after aging in an air‐circulating oven. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2408–2414, 2003     

Preparation and properties of ethylene–propylene–diene rubber/organomontmorillonite nanocomposites

Ethylene–propylene–diene rubber (EPDM)/organomontmorillonite (OMMT) nanocomposites were prepared with a maleic anhydride grafted EPDM oligomer as a compatibilizer via melt intercalation. X‐ray diffraction and transmission electron microscopy indicated that the silicate layers of OMMT were exfoliated and dispersed uniformly as a few monolayers in nanocomposites. The change in the crystallization behavior of the nanocomposites was examined. The nanocomposites exhibited great improvements in the tensile strength and tensile modulus. The incorporation of OMMT gave rise to a considerable reduction of tan δ and an increase in the storage modulus. Moreover, the solvent resistance of the nanocomposites increased remarkably. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 440–445, 2004     

Preparation and properties of polytetrafluorethylene filled ethylene–propylene–diene monomer composites

Ethylene–propylene–diene monomer/polytetrafluorethylene (EPDM/PTFE) composites based on EPDM and electron beam irradiated PTFE powders (MS‐II, MS‐III, and MS‐V, with mean diameter 5 μm, 1 μm, and 0.1 μm, respectively) were prepared by a mechanical compounding technique. The curing characteristics, morphologies, mechanical properties, and abrasion behaviors of these composites were investigated. The curing measurements indicated that the addition of lower loading of MS‐III or MS‐V enhanced the lubrication of EPDM compounds and delayed the curing process. The morphological structure of the composites demonstrated that the MS‐III and MS‐V were uniformly dispersed in EPDM matrix and the efficient polymer–filler interfacial interactions were constructed. In comparison with EPDM/MS‐II and EPDM/MS‐III, EPDM/MS‐V exhibited outstanding tensile strength, tear strength, elongation at break, and abrasion resistance due to the nanometer particle dimension and good dispersion of MS‐V as well as the stronger interfacial interactions between MS‐V and the EPDM matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effect of different types of carbon black on the mechanical and acoustic properties of ethylene–propylene–diene rubber

The effects of the incorporation of different types of carbon black as fillers on some selected physical and mechanical properties of ethylene–propylene–diene rubber (EPDM) based compounds were studied with the results of density, ultrasonic wave velocity, and tensile measurements. Ultrasonic wave velocities (both longitudinal and shear) were measured at frequencies up to 4 MHz at room temperature. The density, ultrasonic attenuation coefficient, and tensile strength results showed that rubber mixes containing general‐purpose furnace (GPF) black at a concentration of 25 phr had the best physical and mechanical properties. These results were interpreted to be due to the better compatibility of GPF black, which, because of its particle size and structure, filled the interstitial spaces in EPDM and provided better reinforcement of the elastomer. The use of a nondestructive technique such as ultrasonic measurement presents a new possibility for testing rubber and plastic products more efficiently. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of a natural magnesium silicate treated with a new coupling agent on the properties of ethylene–propylene–diene rubber compounds

The behavior of sepiolite (magnesium silicate with a microfibrillar morphology) as a filler in ethylene–propylene–diene compounds was studied. A new coupling agent, meta‐isopropenyl dimethyl benzyl isocyanate, was used. The effect of the filler modified by meta‐isopropenyl dimethyl benzyl isocyanate on the physical properties was improved with respect to other fillers and commercial silane coupling agents under the same conditions. In addition to a smoother surface, the flow behavior of compounds filled with sepiolite, on account of its fibrous morphology, was better than that obtained with other fillers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1489–1493, 2004     

Influence of the clay modification and compatibilizer on the structure and mechanical properties of ethylene–propylene–diene rubber/montmorillonite composites

Ethylene–propylene–diene rubber (EPDM)/montmorillonite (MMT) composites were prepared through a melt process, and three kinds of surfactants with different ammonium cations were used to modify MMT and affect the morphology of the composites. The morphology of the composites depended on the alkyl ammonium salt length, that is, the hydrophobicity of the organic surfactants. Organophilic montmorillonite (OMMT), modified by octadecyltrimethyl ammonium salt and distearyldimethyl ammonium salt, was intercalated and partially exfoliated in the EPDM matrix, whereas OMMT modified by hexadecyltrimethyl ammonium chloride exhibited a morphology in which OMMT existed as a common filler. Ethylene–propylene–diene rubber grafted with maleic anhydride (MAH‐g‐EPDM) was used as a compatibilizer and greatly affected the dispersion of OMMT. When OMMTs were modified by octadecyltrimethyl ammonium chloride and distearydimethyl ammonium chloride, the EPDM/OMMT/MAH‐g‐EPDM composites (100/15/5) had an exfoliated structure, and they showed good mechanical properties and high dynamic moduli. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 638–646, 2004     

Photocrosslinking of an ethylene–propylene–diene terpolymer and the characterization of its structure and mechanical properties

An ethylene–propylene–diene terpolymer (EPDM) was photocrosslinked under UV irradiation with benzil dimethyl ketal (BDK) as a photoinitiator and trimethylolpropane triacrylate (TMPTA) as a crosslinker. The efficiency of the photoinitiated crosslinking system EPDM–BDK–TMPTA, various factors affecting the crosslinking process (the photoinitiator and crosslinker and their concentrations, the irradiation time, the temperature, the atmosphere and UV‐light intensity, and the depth of the UV‐light penetration), and the mechanical properties of photocrosslinked EPDM were examined extensively through the determination of the gel contents, infrared spectra, and mechanical measurements. EPDM samples 3 mm thick were easily crosslinked with a gel content of about 90% after 30 s of UV irradiation under optimum conditions. The photoinitiating system of a suitable initiator combined with a multifunctional crosslinker such as BDK–TMPTA enhanced the efficiency of the photocrosslinking reaction, especially by increasing the initial rate of crosslinking. The gel content of photocrosslinked EPDM, which was determined by the content of diene in EPDM, the depth of the UV‐light penetration, and the light intensity, played a key role in increasing the mechanical properties of the photocrosslinked samples in this work. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1837–1845, 2004     

Assessment of crosslink network and network defects of unfilled and filled ethylene‐propylene‐diene terpolymer using solid state nuclear magnetic relaxation spectroscopy

Reinforced rubbers are complex compared to unfilled systems. There are differences in the mechanisms affecting network molecular structure as well as properties of the rubber materials. In this article investigation of crosslink network and untied network defects on a molecular level of unfilled and carbon black filled ethylene‐propylene‐diene terpolymer was carried out using proton solid‐state double‐quantum NMR spectroscopy. The results show that the filled system demonstrates lower cure efficiency in conjunction with more noncoupled network defects than the unfilled one. In addition, the filled system yields the greater spatial heterogeneity because of the localization of the free radicals at the rubber–filler boundary. These strongly influence the mechanical properties of the filled rubber. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44224.     

Physical studies of foamed reinforced rubber composites Part I. Mechanical properties of foamed ethylene–propylene–diene terpolymer and nitrile–butadiene rubber composites

Reinforced ethylene–propylene–diene terpolymer (EPDM) and nitrile–butadiene rubber (NBR) blends were compounded with different concentrations of azodicarbonamide (ADC/K) foaming agent to obtain foamed EPDM and NBR composites. The mechanical properties under compression and under extension at different temperatures were measured for these foams. It was found that the increase of foaming agent concentration and temperature affect all the mechanical parameters. The obtained stress–strain data are discussed in the light of the continuum mechanics theory for compressible materials. © 2002 Society of Chemical Industry     

Physical and mechanical behavior of single‐walled carbon nanotube/polypropylene/ethylene–propylene–diene rubber nanocomposites

The effects of the incorporation of single‐walled carbon nanotubes (SWNTs) on the physical and mechanical properties of thermoplastic elastomers based on blends of isotactic polypropylene (iPP) and ethylene–propylene–diene rubber (EPDM) are described. A marked decrease of the half‐time of PP–EPDM crystallization and a sensible increase of the overall crystallization rate were observed in the presence of SWNTs. These results confirmed the expected nucleant effect of nanotubes on the crystallization of polypropylene. This effect was not linearly dependent on the SWNTs' content, showing a saturation of the nucleant effect at high nanotube concentrations. Dynamic mechanical analysis results showed a significant and controversial change of the mechanical behavior of the PP–EPDM/SWNT composites depending on the nanotube content. In particular, the storage modulus increased at the lowest incorporation of SWNTs, whereas a further increase of nanotubes led to a reduction of the storage modulus with respect to the pristine polymer matrix. Raman spectroscopy and scanning electron microscopy were successfully applied to demonstrate that in the composite films, the changes in the crystallization kinetics and mechanical properties could be explained in terms of the changes of the distance between nanotubes in bundles after a different intercalation of the polymer matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2657–2663, 2003     

Properties of copolymer-type polyacetal/ethylene–propylene–diene terpolymer blends

Two kinds of polymer blends, polyacetals (POMs) and ethylene–propylene–diene terpolymer (EPDM), have been prepared by mechanical blending. The rubbery EPDM was added to the rigid POM matrix to increase toughness. The mechanical, physical, thermal, dynamic mechanical, and morphological properties of these samples have been measured. The notched Izod impact strength and the elongation of the blends reaches a maximum at 7.5 wt % EPDM content. Scanning electron micrographs (SEM) showed that the domain sizes of EPDM vary from 0.25 to 1.0 μm and were independent of the composition. The POM/EPDM blends were determined to be immiscible by SEM, but showed single T_g behavior as determined by differential scanning calorimetry (DSC) and dynamic mechanical analyses up to 7.5 wt % EPDM. Because of that, the T_g's of POM and EPDM were very similar in value. © 1993 John Wiley & Sons, Inc.     

Microwave‐induced devulcanization for poly(ethylene–propylene–diene) recycling

The production of high quantities of end‐of‐life rubbers is an environmental problem of growing importance. Because of their crosslinked nature, such rubbers cannot be easily reprocessed, and actually, they are mainly wasted or reused after a simple mechanical grinding. In this study, a microwave (MW)‐induced thermal treatment at temperatures above 300°C was proposed to obtain partial devulcanization of a poly(ethylene–propylene–diene) (EPDM) rubber filled with carbon black. The use of MWs showed to be a very fast and simple technique, which allowed the production of a treated rubber with a relatively low degree of crosslinking, a slight revulcanization ability, and suitability for reuse in conjunction with virgin rubber. Preliminary mechanical characterization, performed on the revulcanized samples, indicated that the virgin and treated rubber were able to establish a good interface adhesion, which led to performances better than those of similar materials where the recycled part was made of ground untreated EPDM. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Mechanical and morphological properties of white rice husk ash filled polypropylene/ethylene‐propylene‐diene terpolymer thermoplastic elastomer composites

The performance of white rice husk ash (WRHA) as filler for polypropylene (PP)/ethylene‐propylene‐diene terpolymer (EPDM) thermoplastic elastomer (TPE) composites was investigated. The composites with different filler loadings were prepared in a Brabender plasticorder internal mixer. Both unvulcanized and dynamically vulcanized composites were prepared. Mixing and vulcanization processes of the composites were monitored through the typical Brabender torque‐time curves. The mechanical properties and morphology of the composites were also studied. The Brabender torque curves revealed that the dynamic vulcanization process employed was successful and incorporation of filler has no adverse effect on the processibility of the composites. Incorporation of WRHA improves the tensile modulus and flexural modulus and lowers tensile strength, elongation at break, tear strength, and toughness of both types of composites. Dynamic vulcanization significantly enhances the mechanical and TPE properties of the composites. Dynamic mechanical analysis (DMA) study revealed the existence of two phases in both types of composites. It further shows that neither dynamic vulcanization nor filler agglomeration has played a prominent role in the compatibility of the composites. Thermogravimetric investigation shows that dynamic vulcanization or WRHA loading has not adversely affected the thermal stability of the composites. The scanning electron micrographs provide evidence for the tendency to form filler agglomerates with increasing filler loading, better filler dispersion of dynamically vulcanized composites over unvulcanized composites, and effective vulcanization of elastomer phase of the composites in the presence of filler. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 438–453, 2002     

Cure and scorch in the processing of ethylene‐propylene‐diene terpolymer (EPDM)

The objective of this work is to ascertain the characteristics of desirable (cure) and especially undesirable (scorch) crosslinking when carbon black filled ethylene propylene diene terpolymer (EPDM) is processed using different peroxide initiators. The mixing temperature and the nature of the peroxide initiator are crucial parameters affecting scorch (undesirably premature crosslinking) in this rubber. Processability and properties of EPDM prepared using various mixer set temperatures have been investigated. Dicumyl peroxide (Luperox DC), di(t‐butylperoxy) diisopropylbenzene (Luperox F), and 2,5‐dimethyl‐2,5‐di(t‐butylperoxy) hexane (Luperox 101) were used as crosslinking initiators. Higher mixing temperatures give shorter scorch times, greater scorch magnitudes, greater heterogeneities in crosslink spatial distribution and poorer tensile properties. However, extreme localization of the unwanted crosslinking at the rubber‐filler interface does have a beneficial effect. Luperox DC offers poorer processability and poorer resulting properties than do Luperox F and Luperox 101, due to its shorter half‐life and greater solubility in the rubber phase. This is the first time that the spatial heterogeneity of crosslinking and scorch has been related to the basic thermodynamics of 3‐component 2‐phase systems. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44523.