General Properties
Short Name:
Name:
PB
Polybutene
Polybutene has a linear structure and is mainly isotactically structured. The tacticity describes the stereochemistry spatial arrangement of the side chains (in below formula -CH2CH3) in a polymer and strongly infl uences the properties of the corresponding plastic, such as 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, 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 point, 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. There are three types of stereochemistry arrangements: isotactic, atactic and syndiotactic. An arrangement is called isotactic, if all ethyl side chains are on the same side of the polymer backbone. In a syndiotactic arrangement, the ethyl groups alternate from front to back relative to the polymer backbone. An arbitrary arrangement of the side chains is called atactic.
Structural Formula
Properties
NETZSCH Measurement
| Instrument | DSC 204 F1 Phoenix® |
| Sample Mass | 11.06 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 (40 ml/min) |
Evaluation
Along with a 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 -27°C (midpoint) with a Δcp of approx. 0.10 J/(g·K), the semi-crystalline plastic shows an endothermal melting range – quite narrow for plastics – in the 2nd heating (red) with a main peak temperature of 119°C. It can be concluded from this peak shape that the molecular weight distribution is largely homogenous. The corresponding heat of fusion amounts to 42 J/g and is therefore signifi cantly smaller than in the 1st heating (blue, 76 J/g). The smaller downstream melting effect at 129°C in the 2nd heating is much closer to the peak temperature of the main melting effect in the 1st heating (133°C). It can therefore be concluded that during the controlled cooling at a cooling rate of 10 K/min, another crystalline phase formed that was not originally present. 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 at -24°C (midpoint) in the 1st heating is similar to that in the 2nd heating, but it shows a bit smaller step height (Δcp) of 0.08 J/(g·K).