PE-LLD: Polyethylene Linear Low Density

General Properties


Linear low DensityThe mass density is defined as the ratio between mass and volume. density polyethylen (PE-LLD) is different from conventional low-DensityThe mass density is defined as the ratio between mass and volume. density polyethylene (PE-LD, see previous page) in that it shows only short branching and significantly diff erent rheological properties. PE-LLD is a copolymer with usually butylene, hexene or octene and is produced at lower temperatures and pressures than PE-LD.

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-130 to -100 / -70 to -25°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 Temperature122 to 127°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-
Decomposition reactionA decomposition reaction is a thermally induced reaction of a chemical compound forming solid and/or gaseous products. Decomposition Temperature475 to 485°C
Young's Modulus250 to 700 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 Expansion200 *10-6/K
Specific Heat Capacity-
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-
DensityThe mass density is defined as the ratio between mass and volume. Density0.91 to 0.94 g/cm³
MorphologySemi-crystalline thermoplastic
General propertiesBalanced relationship of toughness and stiffness, good chemical resistance, good electrical insulating properties.
ProcessingExtrusion (films, profiles), injection moulding, blow moulding, extrusion-coating.
ApplicationsFilms (allows for lower film thickness than PE-LD), mainly in household and agriculture, packaging (e.g. containers and plastic bags), toys.

NETZSCH Measurement

InstrumentDSC 204 F1 Phoenix®
Sample Mass11.95 mg
IsothermalTests at controlled and constant temperature are called isothermal.Isothermal Phases20 min/2 min/20 min
Heating/Colling Rates10 K/min
CrucibleAl, pierced lid
AtmosphereN2 (40 ml/min)

Evaluation

The 1st heating (blue) exhibits a highly structured melting endotherm with a main peak (at 119°C) and several upstream and downstream shoulders, reflecting the presence of stresses (thermomechanical history). In the 2nd heating (red), two peaks at approx. 112°C and 124°C remained. Due to side chain branching, different melting phases are formed which melt one after the other. The corresponding melting enthalpy in the 2nd heating amounts to approx. 137 J/g. Since PE-LLD is a semi-crystalline thermoplastic, 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 observed at -35°C (for both heatings) can be related to the amorphous component of the polymer. A second possible 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 at approx. -100°C to -130°C, which could be due to the different crystallite structures, is not viewable in the plots shown.