Low-density polyethylene ethylene vinyl acetate copolymer

Hui, S., Chaki, T. K., and Chattopadhyay, S. 2008. Effect of silica-based nanofillers on the properties of a low-density polyethylene/ethylene vinyl acetate copolymer based thermoplastic elastomer. Journal of Applied Polymer Science 110 825-836. 

B. Wang, M. Wang, Z. Xing, H. Zeng, G. Wu, Preparation of radiation crosslinked foams from low-density polyethylene/ethylene vinyl acetate (LDPE/EVA) copolymer blend with a supercritical carbon dioxide approach. J. Appl. Polym. Sci. 127, 912-918 (2013)... 

The low vinyl acetate ethylene—vinyl acetate copolymers, ie, those containing 10—40 wt % vinyl acetate, are made by processes similar to those used to make low density polyethylene for which pressures are usually > 103 MPa (15,000 psi). A medium, ie, 45 wt % vinyl acetate copolymer with mbber-like properties is made by solution polymerisation in /-butyl alcohol at 34.5 MPa (5000 psi). The 70—95 wt % vinyl acetate emulsion copolymers are made in emulsion processes under ethylene pressures of 2.07—10.4 MPa (300—1500 psi). 

A further class of ethylene-vinyl acetate copolymer exists where the vinyl acetate content is of the order of 3 mole %. These materials are best considered as a modification of low-density polyethylene, where the low-cost comonomer introduces additional irregularity into the structure, reducing crystallinity and increasing flexibility, softness and, in the case of film, surface gloss. They have extensive clearance as non-toxic materials. 

The monomers used to make an addition polymer need not be identical. When two or more different monomers are polymerized into the same chain, the product is a copolymer. For instance, we routinely copolymerize ethylene with small percentages of other monomers such as a-olefins (e.g., 1-butene and 1-hexene) and vinyl acetate. We call the products of these reactions linear low density polyethylenes and ethylene-vinyl acetate copolymer, respectively. We encounter these copolymers in such diverse applications as cling film, food storage containers, natural gas distribution pipes, and shoe insoles. 

The properties of ethylene-vinyl acetate copolymers vary widely with their ester content. At the lowest levels of vinyl acetate, they have physical properties that are similar to those of low density polyethylene. As the comonomer content increases, the material becomes less crystalline and more elastic. Copolymers made with the highest comonomer levels contain no measurable crystallinity. The resulting products are tough, flexible, and clear. The ester... 

Polyethylene films for agricultural applications need to have high strength and elasticity, resistance to wind forces, and a long service life. They are mostly produced from low density PE combined with linear, low density PE and ethylene-vinyl acetate copolymer. 

LDPE, low-density polyethylene EVA, ethylene vinyl acetate copolymer Acid copolymers such as ethylene acrylic acid (EAA) or ethylene methacrylic acid (EMA) copolymers... 

The partial molar quantities of mixing were determined for normal and branched alkanes (O5 — Cio), cyclohexane, benzene and tetrachloromethane in polyisobutylene [57]. Partial molar enthalpies of mixing were measured for normal alkenes in low and high density polyethylene, polypropylene, polybutene-1, polystyrene, poly(methyl acrylate), poly(vinyl chloride), polyCN-isopropyl-acrylamide), ethylene-vinyl acetate copolymer, ethylene-carbon oxide copolymer [88] normal, branched and cyclic alkanes, benzene, n-butylbenzene, ois- and ra s-decalin, tetraline and naphthalene in polystyrene at 183, 193 and 203°C [60] these solutes in poly (methyl acrylate) [57] n-nonane, n-dodecane and benzene in polystyrene in the range 104.8 — 165.1 C [71] O7—C, C12 normal alkanes and aromatic hydrocarbons in polystyrene at an average temperature of 204.9°C [72], C7—Cg normal alkanes in poly(ethylene oxide) at an average temperature of 66.5 "C [72] normal alkanes in ethylene oxide—propylene oxide block copolymers (Pluronics L 72, L 64 and F 68) at the same average temperature [72]. 

Ethylene vinyl acetate copolymer (EVA) is a low density polyethylene copolymer with excellent low temperature impact properties. The higher the level of vinyl acetate, the greater the flexibility of the material. Colorants, flame retardants, and foaming and antistatic agents may be added to polyethylene for specialty applications. Comparisons with other resins are given in Table 2. 

The heat distortion temperature at 1.80 Mpa is the temperature that causes a beam loaded to 1.80 to deflect by 0.3 mm. If the heat distortion temperature is lower than the ambient temperature, -20 C is given. Polymers such as low-density polyethylene, styrene ethylene-butene terpolymer, ethylene-vinyl acetate copolymer, polyurethane, and plasticized polyvinyl chloride distort at temperatures below <50°C, whereas others, such as epoxies, polyether ether ketone, polydiallylphthalate, polydiallyl isophthalate, polycarbonate, alkyd resins, phenol formaldehyde, polymide 6,10 polyimide, poly-etherimides, polyphenylene sulfide, polyethersulfone, polysulfonates, and silicones, have remaikably high distortion temperatures in the range of 150°C to >300 C. Thermomechanical analysis has been used to determine the deflection temperature of polymers and sample loading forces (i.e., plots of temperature vs. flexure). 

A second industrial field which has often used Raman spectroscopy and PLS analysis for quantitative modeling is in the production of polymers. PLS has been used on Raman spectra to predict the density of poly(ethylene terephthalate) [3] and polyethylene [73] and Chalmers and Everall mention crystallinity measurements for polyketones [74], Similarly, Sano and co-workers presented a density study of linear low-density polyethylene using PLS and Raman spectroscopy [75]. A subset of these authors have previously shown [45] the prediction of vinyl acetate content in ethylene-vinyl acetate copolymers. PLS was used along with PCA to study the rate constants for a synthesis and hydrolysis of ethyl acetate [29]. 

LDPE films are made of low density polyethylene, linear low density polyethylene (LLDPE), and ethylene-vinyl acetate copolymer, EVA/LDPE blends. 

Olefins are defined as imsaturated aliphatic hydrocarbons. The commercial materials currently used to produce PO foams are low-density polyethylene (LDPE), high-density polyethylene (HDPE), finear low-density polyethylene (LLDPE), polypropylene (PP), and ethylene vinyl acetate copolymers (EVA). The density of a cellular material profoundly affects its properties. PO foams are divided into two density categories high and low density. The borderline is at approximately 240 kg/m [3]. High-density materials are mainly used in wires and cables and for structural purposes. Low-density foams are... 

Low-density polyethylene was utilized as the control (LF-0219-A Novapol). The ethylene-vinyl acetate copolymers varied in vinyl acetate content from 9.3, 18, 28, to 40% (Elvax 760Q, 460, 265, and 40L-03, respectively DuPont). The organomontmorillonites that were evaluated were Cloisite 20A, Cloisite 30B, and montmorillonite exchanged with trimethyl hydrogenated tallow quaternary ammonium ion at the exchange capacity of the montmorillonite. 

Dadfar SMA, Alemzadeh I, Dadfar SMR, Vosoughi M. Studies on the oxygen barrier and mechanical properties of low density polyethylene/organoclay nanocomposite films in the presence of ethylene vinyl acetate copolymer as a new type of compatibihzer. Mater Des 2011 32 1806-1813. 

Liu, Z., Jin, J., Chen, S., Zhang, J. Effect of crystal form and particle size of titanium dioxide on the photodegradation behaviour of ethylene-vinyl acetate copolymer/low density polyethylene composite. Polym. Degtad. Stab. 96, 43-50 (2011)... 

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