What Do P0 and PRI Represent?
Quick AnswerP0 denotes initial plasticity, whereas PRI is the index comparing plasticity retention under specified heat-aging conditions; they are not interchangeable.
Indicator Definitions
Plasticity initial value (P0) describes the initial plasticity of a sample under specified test conditions; the plasticity retention index (PRI) is used to assess the relative retention of plasticity after thermal aging. ISO 2930 specifies the method for PRI determination.
Application
When reviewing the COA, record the applicable standard, test method, batch number, and units. PRI is useful for raw rubber quality evaluation but does not equate to the long-term heat resistance service life of the end product.