EVA: Ethylene Vinyl Acetate

General Properties

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Chemical Formula:

EVA

Ethylene Vinyl Acetate

(C₂H₄)_n(C₄H₆O₂)_m

The properties and applications of polyethylene vinyl acetate (EVA) vary with the percentage of copolymerized vinyl acetate (VA). The VA amount of the present sample amounts to approx. 19 to 20%.

Structural Formula

Properties

Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.Glass Transition Temperature	-40 to +20°C
Melting Temperatures and EnthalpiesThe enthalpy of fusion of a substance, also known as latent heat, is a measure of the energy input, typically heat, which is necessary to convert a substance from solid to liquid state. The melting point of a substance is the temperature at which it changes state from solid (crystalline) to liquid (isotropic melt).Melting Temperature	30 to 110°C
Melting Temperatures and EnthalpiesThe enthalpy of fusion of a substance, also known as latent heat, is a measure of the energy input, typically heat, which is necessary to convert a substance from solid to liquid state. The melting point of a substance is the temperature at which it changes state from solid (crystalline) to liquid (isotropic melt).Melting Enthalpy	10 to 100 J/g
Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. Decomposition Temperature	345 to 360 / 470 to 480°C
Young's Modulus	7 to 120 MPa
Coefficient of Linear Thermal Expansion (CLTE/CTE) The coefficient of linear thermal expansion (CLTE) describes the length change of a material as a function of the temperature.Coefficient of Linear Thermal Expansion	160 to 200 *10^-6/K
Specific Heat Capacity	2.3 J/(g*K)
Thermal ConductivityThermal conductivity (λ with the unit W/(m•K)) describes the transport of energy – in the form of heat – through a body of mass as the result of a temperature gradient (see fig. 1). According to the second law of thermodynamics, heat always flows in the direction of the lower temperature.Thermal Conductivity	0.35 W/(m*K)
DensityThe mass density is defined as the ratio between mass and volume. Density	0.92 to 0.95 g/cm³
Morphology	Semi-crystalline thermoplastic
General properties	High flexibility and toughness, good aging stability, high weather resistance, high gloss.
Processing	Injection moulding
Applications	Textile industry, hot melt adhesive, photovoltaic (embedding agent), agriculture and horticulture (films), cling films, shrink wrappings, shoe soles (VA-amount > 30 %)

NETZSCH Measurement

Instrument	DSC 204 `F1` `Phoenix^®`
Sample Mass	10.65 mg
IsothermalTests at controlled and constant temperature are called isothermal.Isothermal Phase	8 min
Heating/Colling Rates	10 K/min
Crucible	Al, pierced lid
Atmosphere	N₂ (50 ml/min)

Evaluation

In the above graphics, only the 1^st heating (blue) was evaluated since the effects in the 2^nd heating − after controlled cooling – are no longer resolved. In the 1^stheating (blue curve), the Glass Transition TemperatureThe glass transition is one of the most important properties of amorphous and semi-crystalline materials, e.g., inorganic glasses, amorphous metals, polymers, pharmaceuticals and food ingredients, etc., and describes the temperature region where the mechanical properties of the materials change from hard and brittle to more soft, deformable or rubbery.glass transition occurs at -23°C (midpoint, with a change in specific heat of 0.56 J/(g·K)). It is followed by two overlapping, endothermal melting effects at 51°C and 87°C (peak temperatures). The entire heat of fusion of the combined peaks amounts to approx. 75 J/g.