PEMBUATAN DAN KARAKTERISASI PLASTIK BIODEGRADABLE DARI KOMPOSIT HDPE (HIGH DENSITY POLYETHYLENE) DAN PATI UMBI SUWEG (Amorphophallus campanulatus) - Regina Martha Clarinsa; Suyatno Sutoyo (Department of Chemistry, Faculty of Mathematics and Natural Sciences, Surabaya State University, located at Jl Ketintang, Surabaya, East Java, Indonesia, 2021)
Abstrak. Plastik yang berasal dari polimer sintetik menjadi permasalahan lingkungan karena tidak dapat terdegradasi lebih cepat di dalam tanah. Penelitian ini ditujukan untuk membuat plastik biodegradable komposit HDPE dengan pati umbi suweg (HDPE-PSW) serta menentukan komposisi terbaik dari campuran HDPE dengan pati umbi suweg yang memiliki sifat biodegradabilitas yang memenuhi standart SNI. Pati diperoleh dari umbi suweg menggunakan metode ekstraksi dengan pelarut air. Proses pembuatan plastik biodegradable dilakukan dengan metode grafting menggunakan pereaksi maleat anhidrida dan bahan pemlastis berupa gliserol. Variasi komposisi massa HDPE dan pati suweg yang digunakan berturut-turut 8:2, 7:3, 6:4, 5:5, dan 4:6 gram. Sifat biodegradabilitas ditentukan dengan metode Soil Burial Test sedangkan gugus fungsi ditentukan menggunakan spektrofotometer FTIR. Dari proses ekstraksi diperoleh pati dengan rendemen 5,25%. Pati diperoleh dalam bentuk serbuk berwarna putih, tidak berbau, sedikit larut dalam air dan etanol, serta menunjukkan hasil positif dengan pereaksi larutan iodium. Hasil uji biodegradasi menunjukkan bahwa plastik komposit HDPE-PSW 6:4 dan 5:5 mendekati standar SNI karena setelah didegradasi selama seminggu menunjukkan persentase degradasi mendekati 60%, yakni masing-masing 58,9% dan 60,6%. Kedua komposisi plastik HDPE-PSW tersebut juga memiliki persentase degradasi mendekati plastik biodegradable komersial Cassaplast (59,4%). Berdasarkan hasil uji FTIR, plastik biodegradable HDPE-PSW memiliki gugus fungsi yang sama dengan plastik HDPE dan pati umbi suweg. Hal ini menunjukkan bahwa proses grafting dalam pembuatan plastik biodegradable HDPE-PSW telah terjadi. Kata kunci : Plastik biodegradable, pati umbi suweg, HDPE Abstract. Plastic which derived from synthetic polymers is an environmental problem because it couldn’t easily degradation in the ground. This research is aimed to make the biodegradable plastic composite of HDPE with suweg tuber starch (HDPE-PSW) as well as determining the best composition of HDPE-suweg tuber starch mixture which has biodegradability properties according to SNI standards. Suweg tuber made with ekstraction method which uses water solvent. Biodegradable plastics have been processed using grafting method with maleic anhydride reactant and glycerol plasticizer. The varians mass of HDPE plastic and suweg starch are 8:2, 7:3, 6:4, 5:5, and 4:6 grams. Biodegradability of biodegradable plastics depend on Soil Burial Test method meanwhile analysis of functional group depend with FTIR spectrophotometer. From the extraction process obtained starch with a yield of 5.25%. Starch was obtained in the form of white powder, odorless, slightly soluble in water and ethanol, and showed positive results with iodine solution reagent. The biodegradation test results showed that the HDPE-PSW plastic composite of 6:4 and 5:5 approached the SNI standard because after being degraded for a week showed the percentage of degradation was approaching 60% ie 58.9% and 60.6%, respectively. The two HDPE-PSW plastic compositions also had a degradation percentage close to Cassaplast's commercial biodegradable plastic (59.4%). Based on the results of the FTIR test, HDPE-PSW biodegradable plastic had the same functional group as HDPE plastic and suweg tuber starch. This showed that the grafting process in the manufacture of biodegradable HDPE-PSW plastic had taken place. Key words: Biodegradable plastics, suweg tuber starch, HDPE