Analisis Nilai Pri (Plasticity Retention Index) Dan Kadar Nitrogen Karet Alam Dalam Memastikan Kualitas Bahan Baku Untuk Produk Turunan Di Pt Rubber Hock Lie Sunggal

Abstract

Natural rubber is a primary raw material in the rubber processing industry, and its quality is strongly influenced by the Plasticity Retention Index (PRI) and nitrogen content. PRI indicates the rubber’s resistance to thermal oxidation, while nitrogen content reflects the protein level, which can affect the rubber’s stability and physical properties. This research was conducted at PT Rubber Hock Lie Sunggal, with the aim of determining the quality of natural rubber raw materials through the analysis of PRI and nitrogen content. The PRI test was carried out using a Wallace Plastimeter according to the procedure in SNI 06-1903-2017, while nitrogen content was analyzed using the Kjeldahl method. The results showed that the PRI values of the five rubber samples ranged from 69% to 74%, and the nitrogen content ranged from 0.24% to 0.28%. All test results met the quality requirements based on SNI 06-1903-2017, with a minimum PRI value of 50% and a maximum nitrogen content of 0.60%. Therefore, the natural rubber raw materials analyzed are declared suitable and feasible for use in the production of derivative rubber products.