Characterization of epoxidized natural rubber/ethylene vinyl acetate (ENR‐50/EVA) blend: Effect of blend ratio

Epoxidized natural rubber/Ethylene vinyl acetate copolymer (ENR‐50/EVA) blends with different ratios were prepared by using a Haake internal mixer. The effect of the blend ratio on the processing, tensile properties (such as tensile strength, elongation at break, Young's modulus and stress–strain behavior), morphology, dynamic mechanical properties, and thermal properties has been investigated. The tensile properties increase with the increase of EVA content, whereas the stabilization torque increases with the increase of ENR‐50 content in the blend. In 40:60 and 50:50 blend of ENR‐50/EVA, both the phases exist as continuous phases, producing a co‐continuous morphology. At these blend ratio, the drastic change in properties were noted, indicating that the phase inversion occurs. The results on dynamic mechanical properties revealed that the blends are compatible. Blending of ENR‐50 and EVA lead to the improvement in thermal stability and 50:50 blend ratios is the most stable blend. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1504–1515, 2006     

Experimental and computational investigation of EVOH/clay nanocomposites

Ethylene–vinyl alcohol copolymer (EVOH)/organoclay nanocomposites were prepared via a dynamic melt‐intercalation process. The effect of compatibilizers on the melt blending torque, intercalation level, and morphology of EVOH/organoclay systems was investigated. Maleic anhydride grafted ethylene vinyl acetate (EVA‐g‐ MA), or maleic anhydride grafted linear low‐density polyethylene (LLDPE‐g‐MA), were used to compatibilize EVOH with clay, at various concentrations (1, 5, and 10 wt %). Computer‐simulation techniques are used to predict structural properties and interactions of EVOH with compatibilizers in the presence and absence of clay. The simulation results strongly support the experimental findings and their interpretation. X‐ray diffraction shows enhanced intercalation within the galleries when the compatibilizers were added. Interestingly, results were obtained for the EVOH/clay/compatibilizer systems, owing to a high level of interaction developed in these systems. Thermal analysis shows that, upon increasing the compatibilizer content, lower crystallinity levels result, until at a certain compatibilizer content no crystallization is taking place. Significantly higher mixing viscosity levels were obtained for the EVOH/organoclay blends compared with the neat EVOH polymer. The storage modulus was higher compared with the uncompatibilized EVOH/organoclay blend in the presence of EVA‐g‐MA compatibilizer (at all concentrations), and only at low contents of LLDPE‐g‐MA. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2060–2066, 2005     

Processability,property, and morphology of biodegradable blends of poly(propylene carbonate) and poly(ethylene‐co‐vinyl alcohol)

Biodegradable blends of poly(propylene carbonate) (PPC) and poly(ethylene‐co‐vinyl alcohol) (EVOH) were melt compounded in a batch mixer followed by compression molding. The processability, mechanical properties, thermal behavior, and morphologies of the blends were investigated with torque rheometer, Fourier transform infrared spectroscopy, tensile tests, dynamic mechanical analysis, thermogravimetric analysis, differential scanning calorimetry, and scanning electron microscopy. Torque rheometry indicated good interfacial miscibility between PPC and EVOH phases, and then fourier transform infrared spectroscopy spectra demonstrated that a certain extent of hydrogen‐bonding interactions between PPC and EVOH matrix in the blends. A study of the mechanical properties and thermal behavior showed that the EVOH incorporation can significantly enhance the tensile strength, thermal stability, and crystallinity of the blends. Moreover, dynamic mechanical analysis and differential scanning calorimetry both revealed that PPC and EVOH were compatible to some extent. Further, scanning electron microscopic examination also revealed the good interfacial adhesion between EVOH and PPC phases. POLYM. ENG. SCI., 47:174–180, 2007. © 2007 Society of Plastics Engineers     

Preparation and Properties of Ethylene Vinyl Acetate (EVA)/Organoclay/Compatibilizer Nanocomposites: Effects of Organoclay Loading and Methyl Ethyl Ketone

Ethylene vinyl acetate (EVA)/organoclay/compatibilizer nanocomposites were produced using a melt compounding technique in an internal mixer, Haake Rheometer, at 120°C and 50 rpm rotor speed. Effects of organoclay loading (from 2 to 10 phr—parts per hundred of resin and methyl ethyl ketone (MEK), used as a compatibilizer, on the processing properties, tensile properties, morphology, thermal degradation, and water absorption behavior of EVA/organoclay nanocomposites were studied. Results indicate that the presence of organoclay increase the processing torque, tensile properties, thermal degradation, and resistance to water absorption. The optimum organoclay loading was achieved at 2 phr. This was caused by the dispersion state of individual silicate layers (intercalation/exfoliation) in EVA matrix. The intercalation/exfoliation structure affects the properties of EVA/organoclay nanocomposites as evidenced from the morphology studies such as x-ray diffraction (XRD) and transmission electron microscopy (TEM) evaluation. The addition of MEK has the ability to improve the tensile properties, thermal degradation, and slightly reduces the resistance of water permeation of EVA/organoclay nanocomposites. The enhanced properties were seen as a result of the better matrix and filler interaction. The EVA/organoclay/MEK nanocomposites shows better intercalation/exfoliation of individual silicate layers in the EVA matrix as indicated by TEM. Moreover, the XRD evaluation shows that intercalation/exfoliation of the organoclay was formed in the EVA matrix.     

Fracture behaviour of poly[ethylene–(vinyl alcohol)]/organo‐clay composites

BACKGROUND: Ethylene–(vinyl alcohol) (EVOH) copolymer/organo‐modified montmorillonite (OMMT) composites were investigated. Composites with two different percentages by weight of OMMT were prepared using a melt‐extrusion procedure in a twin‐screw extruder, using EVOH as matrix. Films made of EVOH and EVOH/OMMT composites were prepared in a cast‐film extrusion line. RESULTS: The mechanical properties were evaluated by tensile tests and the fracture behaviour was analysed using the essential‐work‐of‐fracture (EWF) method. Fracture characterization was carried out for the two main processing directions: melt flow direction and transverse direction. Fractographic observations were made using scanning electron microscopy. CONCLUSION: The tensile test results indicated good compatibility between EVOH and OMMT. In addition, the fracture tests showed the influence of the clay particle arrangement on the fracture behaviour, showing an increase in the specific essential work of fracture, w_e, which was attributed to the EVOH–OMMT interaction. The plastic term, βw_p, showed different trends depending on the test direction, explained by the size of the plastic zone and the restrictions to the EVOH plastic flow promoted by the clay particles. In this sense, the EWF method is shown to be a very useful tool for the analysis of structure–property relationships in polymer–organo‐clay composites. Copyright © 2009 Society of Chemical Industry     

Effect of chlorine dioxide gas on physical,thermal, mechanical,and barrier properties of polymeric packaging materials

The effects of gaseous chlorine dioxide (ClO₂) on properties and performance of 10 selected polymeric packaging materials, including polyethylene (PE), biaxially oriented poly(propylene), polystyrene, poly(vinyl chloride), poly(ethylene terephthalate) (PET), poly(lactic acid), nylon, and a multilayer structure of ethylene vinyl acetate (EVA)/ethylene vinyl alcohol (EVOH), were evaluated. Physical, mechanical, barrier, and color properties as well as infrared (IR) spectra were assessed before and after polymer samples were exposed to 3600 ppmV ClO₂ gas at 23°C for 24, 168, and 336 h. The IR spectra of the ClO₂‐treated samples revealed many changes in their chemical characteristics, such as the formation of polar groups in the polyolefin, changes in functional groups, main chain scission degradation, and possible chlorination of several materials. The ClO₂‐treated PE samples showed a decrease in tensile properties compared with the untreated (control) films. Decreases in moisture, oxygen, and/or carbon dioxide barrier properties were observed in the treated PE, PET, and multilayer EVA/EVOH/EVA samples. A significant increase (P < 0.05) in the barrier to O₂ was observed in the ClO₂‐treated nylon, possibly the result of molecular reordering, which was found through an increase in the crystallinity of the material. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Fabrication and characterization of HCl‐treated clinoptilolite filled ethylene vinyl acetate composite films

As received and HCl treated Clinoptilolite (C)‐ethylene vinyl acetate (EVA) composites were prepared via the melt‐mixing technique, and extruded through a single‐screw extruder to obtain composite strips with an average thickness of 0.5 mm. The films were then characterized for their morphological, structural, thermal, and mechanical properties. Optical micrographs show that at higher C loading, the particles form large agglomerates, resulting in the formation of voids on the surface of the films. With increasing zeolite loading, the films become brittle, resulting in reduced Young's modulus. Acid treatment of the C tends to affect the crystal structure of the zeolite, resulting in poor tensile properties of the HCl‐treated zeolite‐filled EVA films. Addition of the zeolite also increased the crystallinity of the structure, acting as a nucleating agent in the EVA crystallization. Modeling of the tensile yield data with Pukanszky model indicate that there is poor interfacial adhesion between the polymer matrix and the filler particles. Thermal characterization studies showed that addition of the zeolites retarded the onset degradation temperature of EVA. However, degradation temperatures including T_max and the final decomposed temperature were increased, suggesting improved thermal stability due to reduced inter‐chain mobility in the composite materials as a result of increased zeolite loading. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Thermal and barrier properties of EVOH/EFG nanocomposite films for packaging applications: Effect of the mixing method

Ethylene‐vinyl alcohol copolymer (EVOH)/exfoliated graphite (EFG) nanocomposite films were prepared by precoating EFG on the EVOH surface and conducting a successive melt‐extrusion process. Their physical properties were strongly dependent on the EFG content and the mixing method, which strongly affected the morphology and surface properties of the nanocomposite films. The hydrophobicity and water resistance property of EVOH increased by incorporating hydrophobic EFG and their effects were more pronounced in the precoating method, which is related to good dispersion of EFG in EVOH and an enhanced crystalline structure. The incorporation of EFG into EVOH by the precoating method more effectively diminished the dependence of the relative humidity on the oxygen transmission rate of pure EVOH and increased the oxygen barrier properties of EVOH at a high relative humidity. The incorporation of EFG into EVOH by the precoating method also induced relatively more enhanced thermal stability. These results suggest the feasibility of the application of moisture‐sensitive EVOH resin for food packaging films. POLYM. COMPOS., 37:1744–1753, 2016. © 2014 Society of Plastics Engineers     

Morphology,resistivity, and thermal behavior of EVOH/carbon black and EVOH/graphite composites prepared by simple saponification method

Poly(ethylene‐co‐vinyl alcohol) (EVOH)/carbon black (CB) and EVOH/graphite (GP) electro‐conductive composites were prepared by saponification of poly(ethylene‐co‐vinyl acetate) (EVA)/CB and EVA/GP composites in ethanol/KOH solution. The electrical resistivity change and positive temperature coefficient (PTC) behavior of these composites were investigated. The volume resistivity of EVA/CB and EVA/GP composites was decreased with saponification time. It can be observed that EVA/CB10 and EVA/GP05 composites showed a significant reduction in resistivity after saponification for 1 h. With the increase in saponification time, PTC peak temperature of both composites was shifted at a higher temperature. Tensile properties, morphology, and thermal behavior of the prepared composites have been also evaluated using universal test machine, scanning electron microscopy, and differential scanning calorimetry, respectively. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

The effect of organo‐modifier on the structure and properties of poly[ethylene–(vinyl alcohol)]/organo‐modified montmorillonite composites

Ethylene–(vinyl alcohol) (EVOH)/organo‐modified montmorillonite clay (OMMT) composites were prepared using commercial OMMTs with two different organo‐modifiers. The first one has polar groups, which interact with EVOH chains, whereas the second one is non‐polar. Composites with a high weight percentage of OMMT were prepared by melt‐extrusion in a twin‐screw extruder. Films were prepared in a cast‐film line in order to evaluate the tensile and fracture parameters. The morphology of the EVOH/OMMT composites was characterized using wide‐angle X‐ray scattering and transmission electron microscopy, complemented by image analysis. The mechanical properties were evaluated using uniaxial tensile tests; the fracture behaviour was analysed using the essential work of fracture (EWF) method. Results show differences in composite morphologies and crystalline fraction, depending on the content and the nature of the organo‐modifier. The mechanical and fracture behaviours are strongly influenced by those parameters, which act in opposite senses. The EWF method is shown to be a useful tool for the analysis of the structure–properties relationships of these composites. Copyright © 2010 Society of Chemical Industry     

Ethylene vinyl acetate/ethylene propylene diene terpolymer‐blend‐layered double hydroxide nanocomposites

Ethylene vinyl acetate (EVA‐45)/ethylene propylene diene terpolymer (EPDM) blend‐layered double hydroxide (LDH) nanocomposites have been prepared by solution blending of 1:1 weight ratio of EVA and EPDM with varying amounts of organo LDH (DS‐LDH). X‐ray diffraction and transmission electron microscopy analysis suggest the formation of partially exfoliated EVA/EPDM/DS‐LDH nanocomposites. Measurement of mechanical properties of the nanocomposites (3 wt% DS‐LDH content) show that the improvement in tensile strength and elongation at break are 35 and 12% higher than neat EVA/EPDM blends. Dynamic mechanical thermal analysis also shows that the storage modulus of the nanocomposites at glass transition temperature is higher compared to the pure blend. Such improvements in mechanical properties have been correlated in terms of fracture behavior of the nanocomposites using scanning electron microscopy analysis. Thermal stability of the prepared nanocomposites is substantially higher compared to neat EVA/EPDM blend, confirming the formation of high‐performance polymer nanocomposites. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

Effect of vinyl acetate content on the mechanical and thermal properties of ethylene vinyl acetate/MgAl layered double hydroxide nanocomposites

Ethylene vinyl acetate (EVA)/Mg‐Al layered double hydroxide (LDH) nanocomposites using EVA of different vinyl acetate contents (EVA‐18 and EVA‐45) have been prepared by solution blending method. X‐ray diffraction and transmission electron microscopic studies of nanocomposites clearly indicate the formation of exfoliated/intercalated structure for EVA‐18 and completely delaminated structure for EVA‐45. Though EVA‐18 nanocomposites do not show significant improvement in mechanical properties, EVA‐45 nanocomposites with 5 wt % DS‐LDH content results in tensile strength and elongation at break to be 25% and 7.5% higher compared to neat EVA‐45. The data from thermogravimetric analysis show that the nanocomposites of EVA‐18 and EVA‐45 have ≈10°C higher thermal decomposition temperature compared to neat EVA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

The effect of extrusion processing conditions on EVOH/clay nanocomposites at low organo‐clay contents

Ethylene vinyl alcohol (EVOH) copolymer is studied as a host for low concentrations, up to 1 wt%, of organically treated clay. The clay develops a high interaction level with EVOH and thus high torque levels accompany the structuring process leading to the formation of nanocomposites. Extrusion residence time, successive extrusion passes, screw rotational speed, and processing temperature were all found to affect the morphology and the thermal and mechanical properties of the resulting composites. The extrusion compounded composites were subsequently injection molded. A subtle balance of processing parameters is required to achieve improved properties. Long extrusion residence times were found important for good clay dispersion in some cases, whereas in other cases an exfoliated structure was obtained already after the first extrusion pass. Two organically treated clay types processed at the same conditions were examined, and found to result in different morphology and mechanical behavior. Compression molding of extrusion compounded materials, under several extrusion conditions, was studied to illustrate the effect of shear level on the resulting morphology. The delamination level was higher after compression molding compared to that after injection molding. EVOH thermal properties and thermal stability of the related composites were also examined using differential scanning calorimetry and thermal gravimetric analysis. Higher extrusion processing temperature (220 compared to 200°C) was found to change the crystallization process of EVOH in the presence of clay, leading to significant decrease in T_m and T_c compared to that of the neat EVOH. POLYM. COMPOS., 26:343–351, 2005. © 2005 Society of Plastics Engineers     

Influence of the ethylene–(methacrylic acid)–Zn2+ ionomer on the thermal and mechanical properties of blends of poly(propylene) (PP)/ethylene–(vinyl alcohol) copolymer (EVOH)

The thermal and mechanical properties and the morphologies of blends of poly(propylene) (PP) and an ethylene–(vinyl alcohol) copolymer (EVOH) and of blends of PP/EVOH/ethylene–(methacrylic acid)–Zn²⁺ ionomer were studied to establish the influence of the ionomer addition on the compatibilization of PP/EVOH blends and on their properties. The oxygen transmission rate (O₂TR) values of the blends were measured as well. PP and EVOH are initially incompatible as was determined by tensile tests and scanning electronic microscopy. Addition of the ionomer Zn²⁺ led to good compatibility and mechanical behaviour was improved in all blends. The mechanical properties on extruded films were studied for 90/10 and 80/20 w/w PP/EVOH blends compatibilized with 10 % of ionomer Zn²⁺. These experiments have shown that the tensile properties are better than in the injection‐moulded samples. The stretching during the extrusion improved the compatibility of the blends, diminishing the size of EVOH domains and enhancing their distribution in the PP matrix. As was to be expected, the EVOH improved the oxygen permeation of the films, even in compatibilized blends. Copyright © 2004 Society of Chemical Industry     

Synthesis and properties of random copolymers of 2,2‐dimethyltrimethylene carbonate and ethylene carbonate catalyzed by lanthanide tris(2,6‐di‐tert‐butyl‐4‐methylphenolate)

Random copolymers of 2,2‐dimethyltrimethylene carbonate and ethylene carbonate (EC) were synthesized with lanthanide tris(2,6‐di‐tert‐butyl‐4‐methylphenolate)s [Ln(DBMP)₃; Ln = La, Nd, Sm, or Dy] as catalysts, among which La(DBMP)₃ showed the highest activity. Poly(2,2‐dimethyltrimethylene carbonate‐co‐ethylene carbonate)s [poly(DTC‐co‐EC)]s with high molecular weights were prepared at room temperature and characterized with ¹H‐NMR and size exclusion chromatography. The thermal behavior and crystalline properties of the poly(DTC‐co‐EC)s were analyzed with differential scanning calorimetry, thermogravimetric analysis, and X‐ray diffraction. The crystallinity and melting temperatures of the poly(DTC‐co‐EC)s both decreased with increasing EC content in the copolymers. The mechanical properties of these copolymers were also investigated with dynamic mechanical analysis and tensile strength measurements, which revealed that a reduction of the glass‐transition temperature and great enhancement of the tensile properties could be achieved with higher EC contents. These improvements in the thermal and mechanical properties indicate potential applications in biomedical research for novel polycarbonates. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of the particle size of expandable graphite on the thermal stability,flammability, and mechanical properties of high‐density polyethylene/ethylene vinyl‐acetate/expandable graphite composites

In this article, high‐density polyethylene/ethylene vinyl‐acetate copolymer (HDPE/EVA) composites filled with two different particle sizes (45 and 150 µm) of expandable graphite (EG) were prepared by using a twin‐screw extruder. The thermal stability, flammability, and mechanical properties of HDPE/EVA/EG composites were investigated by thermogravimetric analysis (TGA), cone calorimeter test (CCT), tensile test, and scanning electron microscopy (SEM). The results from TGA and CCT indicated that EG significantly enhanced the thermal stability and fire resistance of HDPE/EVA blend. The thermal stability and flame retardancy of HDPE/EVA/EG composites were improved with decreasing particle size of EG. Although the onset of weight loss of the flame‐retardant composites occurred at a lower temperature than that of HDPE/EVA blend, the flame‐retardant composites produced a large amount of char residue at a high temperature. The consolidated char layer formed a barrier, which could reduce heat, low‐molecular transfer, and air incursion, and thus enhanced the flame retardancy. The data from the tensile test showed that the addition of EG deteriorated the mechanical properties; however, the tensile stress and strain of HDPE/EVA/EG composites increased with decreasing the particle size of EG owing to the strong interface adhesion between polymer matrix and inorganic particles. POLYM. ENG. SCI., 54:1162–1169, 2014. © 2013 Society of Plastics Engineers     

Microstructure and thermal properties of ethylene‐(vinyl acetate) copolymer/rectorite nanocomposites

Ethylene‐(vinyl acetate) copolymer (EVA)/rectorite nanocomposites were prepared by direct melt extrusion of EVA and organo‐rectorite. The microstructures and thermal properties of EVA nanocomposites were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), solid‐state nuclear magnetic spectroscopy, positron annihilation spectroscopy, thermal gravimetric analysis (TGA) and dynamic mechanical analysis techniques. XRD pattern and SEM images show that the intercalated structure is formed and rectorite is finely dispersed in EVA matrix. When organoclay content of the hybrid increases to 7.5 wt%, or pristine rectorite was used instead of organoclay, the crystallization behavior of EVA nanocomposite changes greatly and the ratio of the monoclinic to orthorhombic crystal increases significantly. The relative fractional free volume of the nanocomposite decreases with the increasing organo‐rectorite content, and the values of damping factor (tan δ) for all nanocomposites are lower than that of pure EVA. These facts illuminate that intercalated structure restricts the segment motion and mobilization of polymer chain. TGA results of EVA nanocomposites in air indicate that deacylation of EVA is accelerated because of the catalytic effect and the thermal degradation of the main chain is delayed owing to the barrier effect of silicate layers. Copyright © 2005 Society of Chemical Industry     

Preparation and Characterization of Ethylene Vinyl Acetate (EVA)/Natural Rubber (SMR L)/Organoclay Nanocomposites: Effect of Blending Sequences and Organoclay Loading

Ethylene vinyl acetate (EVA)/natural rubber (SMR L)/organoclay thermoplastic elastomer nanocomposites were melt compounded in an internal mixer, Haake Rheometer, at 120°C and 50 rpm rotor speed. In this paper, we demonstrate the effect of different blending sequences and organoclay loading from 2 to 10 phr (parts per hundred resins) on the tensile properties, morphology, thermal degradation, flammability, and water absorption behavior of EVA/SMR L/organoclay nanocomposites. EVA/SMR L/organoclay TPE nanocomposites were prepared by three different blending sequences, and each exhibited different tensile properties. Results indicated that the presence of organoclay increases the tensile properties, resistance toward thermal degradation, resistance to water permeation, and flame retardancy for all the nanocomposites prepared via different blending sequences. However, the optimum results for all the properties studied were achieved when EVA was blended with organoclay first and SMR L was incorporated later into the blend. The optimum organoclay loading was achieved at 2 phr. Results from scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies showed that at 2 phr organoclay loading, nanostructures of individual silicate layers were achieved, whereas at 8 phr organoclay loading, agglomeration was observed. Flammability of the nanocomposites decreased when the organoclay loading increased.     

The effect of maleated compatibilizers on the structure and properties of EVOH/clay nanocomposites

The effect of compatibilizers on the blending torque, crystallization behavior, intercalation level, thermal stability and morphology of EVOH/treated clay systems was investigated. Maleic anhydride‐grafted ethylene vinyl acetate (EVA‐g‐MA) or maleic anhydride‐grafted linear low density polyethylene (LLDPE‐g‐MA) were used as compatibilizers of EVOH with clay, in various concentrations (1, 5 and 10 wt%). The blends were processed using Brabender Plastograph and characterized by XRD, SEM, DSC, DMTA and TGA. X‐ray diffraction shows advanced intercalation within the galleries when the compatibilizers were added. Unique results were obtained for the EVOH/clay/compatibilizer systems, owing to a high level of interaction developed in these systems, which plays a major role. Thermal analysis showed that with increasing compatibilizer content, lower crystallinity levels result, until at a certain content no crystallization has taken place. Significantly higher viscosity levels were obtained for the EVOH/clay blends compared to the neat polymer, as seen by a dramatic torque increase when processed in the Brabender machine. The DMTA spectra showed lower T_g values for the compatibilized nanocomposites compared to the neat EVOH and the uncompatibilized composites. Storage modulus was higher compared to the uncompatibilized EVOH/clay blend when EVA‐g‐MA compatibilizer was added (at all concentrations), and only at low contents of LLDPE‐g‐MA. TGA results show significant improvement of the blends thermal stability compared to the neat EVOH, and to the uncompatibilized blend, indicating an advanced intercalation.     

Gamma radiation aging of EVA/EPDM blends: Effect of vinyl acetate (VA) content and radiation dose on the alteration in mechanical,thermal, and morphological behavior

A series of ethylene vinyl acetate (EVA)/ethylene‐propylene diene elastomer (EPDM) blends (50/50 ratio) with four types of EVAs were prepared using brabender type batch mixer followed by compression molding. All compression‐molded samples were exposed to gamma radiation at 500, 1000, and 1500 kGy doses and were subjected to mechanical, compression set, thermal and morphological test. The % retention in tensile strength, elongation, and hardness were found higher for higher vinyl acetate (VA) containing radiation aged EVA/EPDM blends. The compression set value was decreased with increase of VA content. The thermal degradation kinetics of high VA containing irradiated blend (EVA40/EPDM) (EVA40 is 40%VA containing EVA) was found slower than those of lower VA containing blend (EVA18/EPDM). The surface morphology for EVA18/EPDM sample was transformed into more irregular one with more cracks and fragmented segments by aging at 1500 kGy dose while surface for EVA40/EPDM sample was found comparatively smooth, fine, and continuous with very few cracks and fragmented parts at similar dose. Thus, from the measured properties and morphology, it was revealed that the degree of degradation of blends kept on decreasing with increase in VA content. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46216.