ASTM D 3194 - 17 Standard Test Method for Rubber From Natural Sources - Plasticity Retention Index (PRI)

Current edition approved Jan. 1, 2017. Published January 2017. Originally approved in 1973. Last previous edition approved in 2009 as D3194 – 04 (2009). — 3 p.
This test method gives an indication of the oxidation resistance of raw natural rubber at a specified temperature. This resistance is indicated by the Plasticity Retention Index (PRI), a ratio expressed as a percentage of the aged plasticity to the original plasticity determined by means of a parallel plate plastometer. A low PRI value indicates a poor resistance to oxidation.