Ethylene vinyl acetate mechanical properties

Coran and Patel [33] selected a series of TPEs based on different rubbers and thermoplastics. Three types of rubbers EPDM, ethylene vinyl acetate (EVA), and nitrile (NBR) were selected and the plastics include PP, PS, styrene acrylonitrile (SAN), and PA. It was shown that the ultimate mechanical properties such as stress at break, elongation, and the elastic recovery of these dynamically cured blends increased with the similarity of the rubber and plastic in respect to the critical surface tension for wetting and with the crystallinity of the plastic phase. Critical chain length of the rubber molecule, crystallinity of the hard phase (plastic), and the surface energy are a few of the parameters used in the analysis. Better results are obtained with a crystalline plastic material when the entanglement molecular length of the... 

Chattopadhyay S., Chaki T.K., and Bhowmick A.K., New thermoplastic elastomers from poly(ethyle-neoctene) (engage), poly(ethylene-vinyl acetate) and low-density polyethylene by electron beam technology structural characterization and mechanical properties. Rubber Chem. TechnoL, 74, 815, 2001. Roy Choudhury N. and Dutta N.K., Thermoplastic elastomeric natural rubber-polypropylene blends with reference to interaction between the components. Advances in Polymer Blends and Alloys Technology, Vol. 5 (K. Finlayson, ed.), Technomic Publishers, Pensylvania, 1994, 161. 

Blends of ethylene-vinyl acetate (EVA) copolymer with metallocene-catalysed elastomeric ethylene-alpha-olefin copolymer were investigated and were found to be immiscible in the melt and solid state but mechanically compatible. The morphology (SEM), thermal (DSC), rheological (viscosity), mechanical (including tensile, shear thinning and elastic behaviour) and optical properties of EVA-rich and ethylene-alpha-olefin copolymer-rich blends were studied and the results are discussed in terms of processibility in film applications. 24 refs. 

One the attempt to give improved mechanical properties to TPX is to laminate the polymer and a resin containing polar groups, such as ethylene vinyl acetate and PA. These polymers exhibit excellent gas barrier properties, and the lamination of TPX makes an improvement in the gas barrier properties. Furthermore, PA, in particular biaxially-oriented PA, shows an excellent rigidity, toughness, impact resistance (4). 

Camino, G., Maffezzoli, A., Braglia, M., De Lazzaro, M., and Zammarano, M., Effect of hydroxides and hydroxycarbonate structure on fire retardant effectiveness and mechanical properties in ethylene-vinyl acetate copolymer, Polym. Deg. Stab., 74(3), 457-A64, December, 2001. 

Internal plasticizers are synthesized by copolymerization of suitable monomers. Polymeric non-extractable plasticizers, mostly copolymers having substantially lower glass transition temperatures due to the presence of plasticizing ( soft ) segments such as poly(ethylene-co-vinyl acetate) with approximately 45 % vinylacetate content, ethylene-vinyl acetate-carbon monooxide terpolymer, or chlorinated PE, are available for rather special applications in medicinal articles (Meier, 1990). In this case, the performance of the internally plasticized polymers is the principal advantage. However, copolymerization may account for worse mechanical properties. A combination with external plasticizers may provide an optimal balance of properties. For example, food contact products made from poly(vinylidene chloride) should have at most a citrate or sebacate ester based plasticizers content of 5 % and at most 10 % polymeric plasticizers. 

The most widely used thermoplastic polymer is the ethylene—vinyl acetate copolymer, which is obtainable in a wide range of molecular weights as well as in a variety of compositions. Often flexibilizers or plasticizers are added in order to improve both the mechanical shock resistance and the thermal properties of the adhesive. Polybutenes, phthalates, and tricresyl phosphate have been used as plasticizers. Tackifying agents can also be added. Because hot-melt adhesives are frequendy ethylene-based, they are subject to oxidation if, as in a typical situation, the adhesive sits in an applicator for long periods before use. Thus, antioxidants such as hindered phenols are often used, as are fillers. Fillers are added to opacify or to modify the adhesive s flow characteristics, as well as to reduce cost. Wax is also a very important component. Wax alters surface characteristics by decreasing both the liquid adhesive s surface tension and its viscosity in the melt. Upon solidification, however, the wax acts to increase the strength of the adhesive. Both paraffin and microcrystalline wax are used (see Waxes). 

Wang, B., Wang, X., Shi, Y. et al. 2012. Effect of vinyl acetate content and electron beam irradiation on the flame retardancy, mechanical and thermal properties of intumescent flame retardant ethylene-vinyl acetate copolymer. Radiation Physics and Chemistry 81 308-315. 

Wood-filled PVC has inferior mechanical properties because of lack of interaction. Treatment of wood filler with aminosilane improves acid-base interaction between filler and polymer to the extent that impact strength and tensile properties of composite are improved over unfilled PVC. Tensile properties of PVC were deteriorated when leather particles were used as a filler. But, after filler particles were treated with ethylene-vinyl acetate copolymer, a coating was produced on the surface of filler particles that promoted adhesion with PVC and improved mechanical properties.These are some recent examples of many applications of filler preparations to improve its interaction with PVC. 

K.A. Tawab, S.M. Ibrahim, M.M. Magida, The effect of gamma irradiation on mechanical, and thermal properties of recycling polyethylene terephthalate and low density polyethylene (R-PET/LDPE) blend compatibilized by ethylene vinyl acetate (EVA). J. Radioanal. Nucl. Chem. 295, 1313-1319 (2013)... 

Poomalai, P, Ramaraj, B., and Siddaramaiah. 2007. Thermal and mechanical properties of poly (methyl methacrylate) and ethylene-vinyl acetate co-polymer blends. Journal of Applied Polymer Science 106 (1) 684-691. 

Proposed mechanism of crosslinking for epoxidized natural rubber (ENR) and ethylene vinyl acetate (EVA) with HVA-2. (From Zurina, M., Ismail, H., Ratnam, C., The effect of HVA-2 on properties of irradiated epoxidized natural rubber (ENR-50), EVA, and ENR-50/EVA blend. Polymer Testing 2008,27, 480-490. With permission.)... 

Thomas, S., Gupta, B. R., De, S. K., Mechanical properties, surface morphology and failure mode of gamma-ray irradiated blends of polypropylene and ethylene-vinyl acetate rubber. Polymer Degradation and Stability 1987,18(3), 189-212. 

Alexandre, M. Dubois, P. (2007) Mechanical Properties and Flame-Retardant Behavior of Ethylene Vinyl Acetate/High-Density Polyethylene Coated Carbon Nanotube Nanocompwsites. Adv. Punct. Mater. Vol.l7, No.l5, pp.2787-2791 Pierard, N. Fonseca, A. Konya, Z. Willems, I. Van-Tendeloo, G. Nagy, J. (2001) Production of short carbon nanotubes with open tips by ball milling. Chem. Phys. Lett Vol.335, No.1-2, pp.1-8... 

T. Kuila, P. Khanra, A.K. Mishra, N.H. Kim, and J.H. Lee, Functionalized-graphene/ethylene vinyl acetate co-polymer composites for improved mechanical and thermal properties. Polymer Testing, 31 (2), 282-289,2012. 

Kuila, T., Acharya, H., Srivastava, S. K., and Bhowmick, A. K. 2008. Effect of vinyl acetate content on the mechanical and thermal properties of ethylene vinyl acetate/Mg-Al layered double hydroxide nanocomposites. Journal of Applied Polymer Science 108 1329-1335. 

Shi, Y, Kashiwagi, T., Walters, R. N., Gilman, J. W., Lyon, R. E., and Sogah, D. Y. 2009. Ethylene vinyl acetate/layered silicate nanocomposites prepared by a surfactant-free method Enhanced flame retardant and mechanical properties. Polymer 50 3478-3487. 

Using field-based models, it is more difficult to provide information about the chain conformation on the surface however, attempts have been made to understand phase separation and mechanical properties of composites. Shou et al. combined SCF/DFT techniques with lattice spring model (LSM) to study the effects of the spatial distribution and aspect ratio of particles (rods and spheres) on the mechanical properties of the composite. Buxton and Balazs combined TDGL theory for polymer blends with BD for nanorods in the simulations of nanocomposites. i A percolating network of nanorods was identified in the minority phase of a bicontinuous structure. Clancy and Gates developed a hybrid model for CNTs in a bulk poly(ethylene vinyl acetate) matrix. Molecular structures of... 

Ethylene-vinyl acetate copolymers, usually known as EVA, are used in many applications, but especially for low voltage cables. These polymers are easily flammable and flame retardants are added to reduce their flammability. The classic solution is to incorporate aluminium hydroxide or magnesium hydroxide that develop endothermic reactions when heated. Nevertheless, large amounts have to be incorporated, often around 60% and this can lead to a loss of mechanical properties in the compound. Intumescent technology that works well with polypropylene has also been tried for EVA polymer systems. 

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