Testing of Uncured Rubber

Batch Control

Batch control is the term used for the tests, which entails that each batch of mixed rubber is checked prior to it being used in any advance processing. The testing can include the determination of cure curve, density, viscosity and hardness.

Viscosity-Plasticity

In the processing of rubber, it is vital that the material has appropriate viscosity for the purpose. If the viscosity is too low, the material will not be easy to process, for example due to increased stickiness, low strength and cold flow. If the viscosity is very high, processing requires significant amounts of power and energy. The mechanical energy used in the processing is changed into heat, which raises the risk of scorching. Measuring the viscosity of rubber polymers and compounds is thus one of the more standard controls when producing rubber.

The term “plasticity” is frequently used simultaneously with “viscosity”. High plasticity is the same as low viscosity. Rubber polymers and rubber compounds have very complex flow properties or rheological properties as they are also known. For usual liquids of low viscosity (Newtonian fluids) such as water, one single material constant – viscosity – is enough to be able to characterize their flow properties.

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