General Properties
Short Name:
Name:
CM
Chlorinated polyethylene rubber
Chlorinated polyethylene, abbreviated CM or CPE, is formed by the direct reaction of polyethylene with chlorine. The properties of the resulting rubber are dependent on the chlorine content and distribution. The typical chlorine content is between approx. 25% and 48%. Added stabilizers prevent elimination of the chlorine from the polymer.
Structural Formula
Properties
| Glass Transition Temperature | -25 to -5°C |
|---|---|
| Melting Temperature | - |
| Melting Enthalpy | - |
| Decomposition Temperature | 320 to 340 / 465 to 480°C |
| Young's Modulus | 2 to 15 MPa |
| Coefficient of Linear Thermal Expansion | 175 to 200 *10-6/K |
| Specific Heat Capacity | - |
| Thermal Conductivity | 0.11 to 0.13 W/(m*K) |
| Density | 1.08 to 1.27 g/cm³ |
| Morphology | Amorphous rubber |
| General properties | Good ozone and UV light resistance |
| Processing | Cross linking by means of peroxides with activators, radiation or by means of thiazoles |
| Applications | Cable sheathings. Technical rubber products. Hoses for engines. Impact modifier for PVC |
NETZSCH Measurement
| Instrument | DSC 204 F1 Phoenix® |
| Sample Mass | 14.21 mg |
| Isothermal Phase | 5 min |
| Heating/Colling Rates | 10 K/min |
| Crucible | Al, pierced lid |
| Atmosphere | N2 (40 ml/min) |
Evaluation
As an entirely amorphous polymer, CM shows a glass transition step at -11°C (midpoint, both heatings). The glass transition temperature determines the minimal application temperature* for rubber materials. Below the glass transition, the polymer loses elasticity and gets hard and brittle. The step height (Δcp) is evaluated as 0.49 J/(g.K) in both heatings.
* DIN 3761-15 - Rotary shaft lip type seals for automobils; test; determination of cold resistant of elastomers; differential-thermoanalysis (withdrawn)