CR: Chloroprene rubber

General Properties

Short Name:

Name: 

CR

Chloroprene rubber


Chloroprene rubber (CR) is sometimes also called chlorobutadiene rubber since it is produced from 2-chlorine-1,3-butadiene (chloroprene). The ratio between the trans and cis position of the double bonds is approx. 9:1. Depending on the production process, different CR types are available.

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-45 to -30°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 Temperature40 to 75°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 Enthalpy1 to 10 J/g
Decomposition Temperature365 to 380 / 445 to 460°C
Young's Modulus-
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 Expansion185 to 250 *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 Conductivity0.18 to 0.20 W/(m*K)
DensityThe mass density is defined as the ratio between mass and volume. Density1.25 g/cm³
MorphologyRubber
General propertiesGood mechanical properties and elasticity. Good ozone, weather, chemical and aging resistance. High non-inflammability
ProcessingThermally with diamine, with hydroxyphenyl or a mixture of zinc and magnesium oxides or by reaction with ethylenethiourea
ApplicationsTechnical rubber goods (e.g., seals, profiles). Automobile industry. Electrical industry. Textile industry. Adhesives, hoses, coatings

NETZSCH Measurement

InstrumentDSC 204 F1 Phoenix®
Sample Mass21.18 mg
IsothermalTests at controlled and constant temperature are called isothermal.Isothermal Phase8 min
Heating/Colling Rates10 K/min
CrucibleAl, pierced lid
AtmosphereN2 (40 ml/min)

Evaluation

As an amorphous polymer, CR shows 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 approx. -35°C (midpoint) in both heatings with a step height (Δcp) of 0.38 J/(g*K) in the 2nd heating (red). The small endothermal effect at 45°C (peak temperature) in the 1st heating (blue) is probably due to the melting of an additive, which, in the molten state, dissolves in the elastomer matrix and is therefore no longer visible in the 2nd heating (red).