Penentuan Nilai Plasticy Retention Index (PRI) pada Crumb Rubber Mutu Sir 20 di PT. Rubber Hock Lie Sunggal

Abstract

Plasticy Retention Index (PRI) is a measure of rubber's resistance to wear and tear or oxidation at high temperatures. The PRI value was measured from the comparison of the plasticity value of the rubber before being burnt (P0) and the plasticity value of the rubber after being burnt for 30 minutes at 140°C (P30). The PRI test on the SIR 20 Crumb Rubber sample was carried out using the Wallace Rapid Plastimeter method. From the results of tests that have been carried out in the PT Rubber Hock Lie Sunggal laboratory are 71, 70, 71 72 and 70. Based on the Regulation of the Minister of Trade no. 26 of 2021, one of which regulates the application of SPPT SNI 1903: 2017 includes technical specifications for natural rubber of Standard Indonesian Rubber (SIR), the parameter value of Plasticy Retention Index (PRI) is at least 40. The results of this test indicate that the sample has met the quality requirements set by the government. A high PRI value indicates that rubber has a molecular chain that is resistant to degradation by oxidation. Meanwhile, a low PRI value indicates that rubber is easily oxidized to become soft rubber.