Sintesis dan Karakteristik Aerogel Selulosa Mikrofibril (MFC) dengan Penambahan Lignin dan Silika Jerami Padi

Abstract

Jerami padi mengandung polimer seperti lignin, selulosa mikrofibril (MFC) dan silika yang dapat dimanfaatkan menjadi aerogel ramah lingkungan. Beberapa teknologi pembuatan aerogel berbasis MFC, lignin dan silika telah dilaporkan sebelumnya, tetapi kombinasi ketiga polimer tersebut belum dikembangkan. Penambahan lignin dan silika diharapkan dapat meningkatan stabilitas termal dan kemampuan insulasi termal aerogel. Penelitian ini bertujuan untuk menentukan karakteristik MFC, lignin, silika dan aerogel MFC dengan penambahan lignin dan silika jerami padi. Isolasi MFC dilakukan melalui pemasakan soda, pemutihan dan hidrolisis asam, isolasi lignin menggunakan asam fosfat serta ekstraksi silika menggunakan asam klorida. Aerogel disintesis menggunakan pelarut NaOH-urea (1:4) dan pengeringan beku. Hasil penelitian menunjukkan MFC memiliki kandungan a-selulosa 69,72% dan kristalinitas 80%, sedangkan lignin dan silika memiliki kemurnian 54,24% dan 86,25%. Kerapatan dan porositas aerogel berada pada rentang 0,089-0,114 g/cm3 dan 93,1-94,2%. Analisis SEM menunjukkan lignin dan silika mengisi pori-pori aerogel. Penambahan lignin dan silika pada aerogel MFC dengan nisbah (3:1:2) atau ALS 2 menghasilkan konduktivitas termal terendah dan stabilitas termal tertinggi sehingga menjadi variabel paling optimal untuk insulasi termal.

Rice straw comprises lignocellulosic chemical components, including lignin and cellulose, and cellulose can be converted into microfibril cellulose (MFC). Additionally, it contains significant amounts of inorganic constituents such as silica. They can be used to create eco-friendly aerogels. While technologies based on MFC, lignin, and silica exist, their combined effects remain unexplored. The addition of lignin and silica aims to enhance the thermal stability and insulation properties of aerogel. This study focused on determining the characteristics of MFC, lignin, silica, and MFC aerogels incorporating rice straw lignin and silica in various compositions. Cellulose microfibrils were isolated using soda pulping, followed by bleaching and acid hydrolysis. Lignin was extracted through phosphoric acid precipitation, while silica extraction was conducted using hydrochloric acid. Aerogels were synthesized utilizing a NaOH-urea solvent in a 1:4 ratio through the freeze-drying technique. The findings indicated that the MFC had an a -cellulose content of 69.72% with a crystallinity of 80%, while the lignin and silica exhibited purities of 54.24% and 86.25%, respectively. The density and porosity of the aerogels ranged from 0.089 to 0.114 g/cm³ and 93.1% to 94.2%. SEM analysis revealed that lignin and silica occupied the pores of the aerogel. The addition of lignin and silica to the MFC aerogel in a ratio of 3:1:2, referred to as ALS 2, resulted in the lowest thermal conductivity and highest thermal stability, indicating it as the most optimal variable for thermal insulation.