Karakteristik Perekat Bio-Poliuretan Non-Isosianat Berbasis Tanin Kulit Kayu Mangium

Abstract

Perekat tanin non-isosianat bio-poliuretan (T-NIPU) diformulasikan sebagai altenatif perekat poliuretan isosianat. Penelitian ini bertujuan karakterisasi bahan baku T-NIPU serta mengevaluasi pengaruh jenis formula terhadap karakteristik T-NIPU. Bahan baku T-NIPU berupa tanin hasil ekstraksi kulit kayu mangium (Acacia mangium Wild) sebagai subtitusi poliol, dimetil karbonat (DMC) dengan heksametilentetraamina (HMTA) sebagai subtitusi isosianat, dan water glass (WG) sebagai filler dikarakterisasi. Bahan baku disintesis menjadi T-NIPU dalam 3 formula dengan perbedaan bobot WG. T-NIPU kemudian dikarakterisasi kadar padatan, pH, waktu gelatinasi, reologi, hidrolisis, dan FTIR. Kadar padatan ekstrak tanin sebesar 94,54% dengan rendemen 21,70%. Karakteristik bahan baku kenampakan tidak berwarna kecuali tanin dengan pH bahan HMTA dan WG cenderung basa kuat mengakibatkan perekat memiliki kenampakan hitam dengan pH basa. Peningkatan WG dalam formula T-NIPU meningkatkan kadar padatan, pH, dan reologi perekat, serta hidrolisis (mass loss (MS) dan pH larutan), tetapi mempercepat waktu gelatinasi. Analisis gugus fungsi menunjukkan terdeteksinya ikatan uretan (–NHCOO–) pada sintesis T-NIPU, penambahan water glass menunjukkan pergeseran gelombang pada wilayah fingerprint.

Tannin-based non-isocyanate bio-polyurethane adhesive (T-NIPU) is prepared as an alternative to isocyanate polyurethane (PU) adhesives. This study aims to characterize T-NIPU adhesives and evaluate the influence of water glass (WG) on T-NIPU characteristics. The T-NIPU adhesives were formulated utilizing tannins extracted from mangium bark (Acacia mangium wild) as a polyol, dimethyl carbonate (DMC), hexamethylenetetramine (HMTA), and WG. The material is synthesized in three formulas with different WG weights. T-NIPU was then characterized by solid content, pH, gelation time, rheology, hydrolysis, and FTIR. The results showed that the solid content of tannin extract was 94.54%, with a yield of 21.70%. Except for tannins, the characteristics of the materials are colorless. The pH of HMTA and WG materials tends to be alkaline, resulting in adhesives that have an alkaline appearance. The addition of WG to the T-NIPU formula not only increases the solids content, pH, rheology, mass loss, and pH of the hydrolysed solutions, but also speeds up the gelation time. FTIR showed the detection of urethane bonds (–NHCOO–) in the synthesis of T-NIPU.