SYNTHESIS OF REVERSE ESTER ORGANIC TIN THERMAL STABILIZER FOR POLYVINYL CHLORIDE FROM RICE BRAN FATTY ACID

• Main Author: Rahmawati, Novia
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/83295
• Institution: Institut Teknologi Bandung

PVC is a polymer with low heat stability, thus requiring heat stabilizers during its processing. One commonly used heat stabilizer is organic tin reverse ester stabilizer (TOEB).Commercially, this stabilizer is produced from pine fatty acids or Tall Oil Fatty Acid (TOFA), which is a byproduct of Crude Tall Oil (CTO) fractionation. The production of CTO is decreasing as it is derived from forest resources with diminishing raw material availability. Meanwhile, the demand for CTO is increasing because it is being used as a raw material for biofuel. This situation necessitates the search for alternative raw materials for producing TOEB stabilizers. Indonesia is one of the world's rice producers. Rice is obtained from the milling process of paddy, which generates a byproduct called rice bran. In Indonesia, the estimated production of rice bran is about three million tons per year. Rice bran contains 15–19,7% oil, with the fatty acid content and composition similar to those in TOFA. Additionally, rice bran contains active lipase enzymes that can convert triglycerides into free fatty acids. Therefore, rice bran is considered a potential alternative raw material for producing TOEB. This study aims to produce TOEB stabilizers from crude rice bran fatty acid (CRFA) and compare its characteristics and performance with TOEB obtained from refined rice bran fatty acid (RRFA) and TOFA. The synthesis of TOEB was conducted in two reaction stages. The first stage involves the reaction between fatty acids and mercaptoethanol to produce mercaptoethyl fatty acid (MEAL). The second stage involves the reaction between MEAL and methyl tin chloride (MTC) to produce TOEB. To determine the effect of reactant ratios on the characteristics of the resulting TOEB, the reactant compositions in the TOEB synthesis were varied with MTC to MEAL ratios of 10% deficit, stoichiometric, and 10% excess. The stabilizer dosage was varied at 0,25 phr, 0,5 phr, and 1 phr to assess the effect of dosage on PVC stability. The characteristics of the resulting MEAL and TOEB were tested using FTIR spectra. MEAL analysis was performed by measuring the thiol content and free fatty acid content. TOEB analysis was performed by measuring the sulfur and tin content. The stabilizing effect was examined using static testing with DHC and dynamic testing with a two roll mill. This study successfully produced TOEB with a sulfur content of 6,0–6,7% and a tin content of 10,6–11,4%. The purity of the resulting TOEB was estimated to range between 75–84%. The success of the TOEB synthesis was confirmed by FTIR spectral testing. CRFA produced TOEB with slightly lower purity, sulfur content, and tin content compared to TOEB from RRFA and TOFA but did not show significant performance differences. The difference in raw material purity did not significantly impact the stabilizing effect. DHC test results with varying stabilizer dosages indicated that PVC with a 1 phr stabilizer dosage provided the best induction and stabilization time. Based on sulfur content, tin content, and stabilizing effect, TOEB synthesized with stoichiometric reactant ratios had better results compared to excess and deficit TOEB. The results of this study are expected to contribute to science and technology. Scientifically, this research adds information and understanding about the synthesis of TOEB from alternative raw materials and the resulting thermal stabilization effects. Practically, this research can enhance the sustainability of TOEB stabilizer production by providing alternative raw materials to substitute the increasingly limited availability of TOFA. Additionally, this study contributes to reducing environmental pollution by producing eco-friendly heat stabilizers that have the potential to replace lead stabilizers. The research also provides new insights into products that can be derived from rice bran.