PENGARUH SUHU POLIMERISASI L-ASAM LAKTAT MELALUI METODE RING OPENING POLYMERIZATION (ROP) TERHADAP KARAKTERISTIK POLYLACTIC ACID (PLA) (POLYMERIZATION TEMPERATURE EFFECT OF L-LACTIC ACID BY ROP METHOD ON PLA CHARACTERISTICS)

Abstract

Abstrak. Penelitian ini bertujuan untuk mengetahui pengaruh suhu polimerisasi terhadap karakteristik PLA yang meliputi viskositas, massa molekul, dan titik leleh. Viskositas  PLA diukur menggunakan viskometer Ostwald sehingga didapatkan viskositas intrinsik yang dapat dihubungkan melalui persamaan Mark-Houwink-Sakurada untuk mendapatkan massa molekul PLA. Titik leleh PLA dianalisis dengan  Differensial Scanning Calorimetry (DSC). Hasil penelitian menunjukkan bahwa suhu  polimerisasi L-asam laktat melalui metode ring opening polymerization (ROP) berpengaruh terhadap viskositas dan massa molekul PLA. Viskositas dan massa molekul PLA meningkat seiring dengan suhu polimerisasi yang semakin besar hingga mencapai suhu polimerisasi 140°C, kemudian terjadi penurunan pada suhu polimerisasi 160°C. Titik leleh PLA pada suhu polimerisasi 100°C, 120°C, 140°C, dan 160°C berturut-turut 157,82°C, 157,91°C, 164,41°C dan 161,97°C.

Kata kunci      : PLA, viskositas, massa molekul, titik leleh.

Abstract. The purpose of the research is to determine the effect of polymerization temperature on the characteristics of the PLA, including viscosity, molecular weight and melting point. PLA viscosity was measured using Ostwald viscometer, so the intrinsic viscosity which obtained could be connected with the Mark-Houwink-Sakurada equation to obtain the molecular weight of PLA. The melting point of PLA were analyzed with Differential Scanning Calorimetry (DSC). The result showed that polymerization temperature of L-lactic acid by ring opening polymerization (ROP) method influence to viscosity and molecular weight of PLA. Viscosity and molecular weight of PLA increased by  increasing polymerization temperature until reach polymerization temperature 140°C, then appear decreasing polymerization temperature at 160°C. Melting point of PLA at polymerization temperature 100°C, 120°C, 140°C and 160°C respectively 157.82°C, 157.91°C, 164.41°C and 161.97°C.

Keywords: PLA, viscosity, molecular weight, melting point