Karakteristik Rami Terimpregnasi Bio-Poliuretan Non-Isosianat Berbasis Tanin Terglioksalasi dengan Pelapisan Flame Retardant | Characteristics of Ramie Impregnated with Bio-Based Non-Isocyanate Polyurethane from Glyoxalated Tannin and Flame Retardant Coating

Penggunaan serat sintetis yang tidak ramah lingkungan masih mendominasi industri tekstil Indonesia. Sementara itu, kebutuhan serat alami seperti kapas belum terpenuhi secara domestik. Pengembangan serat alternatif lokal menjadi langkah strategis menuju kemandirian bahan baku tekstil. Serat rami (Boehmeria nivea (L.) Gaudich) merupakan salah satu serat alam potensial karena kandungan selulosa yang tinggi dan kekuatan mekanik yang baik. Rami bersifat mudah terbakar dan higroskopis, sehingga memerlukan perbaikan melalui impregnasi menggunakan resin bio-poliuretan non-isosianat tanin terglioksalasi (Bio-PUNI-TG). Penelitian ini bertujuan menganalisis karakteristik ekstrak tanin, menentukan formula impregnan terbaik yang dibuat dari Bio-PUNI-TG, serta menganalisis karakteristik serat dan kain rami yang diimpregnasi pada waktu berbeda dan terlapisi flame retardant, serta perbandingannya dengan tekstil tahan api komersial. Tanin diekstraksi dari kulit kayu mangium melalui maserasi dengan air panas, kemudian dikarakterisasi. Resin Bio-PUNI-TG disintesis dengan mencampurkan ekstrak tanin, glioksal, dimetil karbonat, dan heksametilentetramin. Optimasi formulasi dilakukan menggunakan metode Response Surface Methodology (RSM). Formula terbaik kemudian dianalisis meliputi kadar padatan, pH, gugus fungsi, dan sifat reologi. Selanjutnya, serat dan kain rami diimpregnasi menggunakan formula terbaik hasil optimasi dan dilapisi flame retardant. Karakterisasi serat dan kain rami sebelum dan sesudah perlakuan meliputi analisis struktur kimia (FTIR, FE-SEM-EDX), sifat mekanik (uji tarik), ketahanan terhadap degradasi (uji hidrolisis), dan ketahanan api (uji flammability). Hasil ekstraksi tanin dari kulit kayu mangium melalui maserasi air panas menunjukkan rendemen 22,71% dan bilangan stiasny sebesar 72,75%. Ekstrak tanin teridentifikasi mengandung gugus hidroksil sehingga memungkinkan penggunaannya sebagai substitusi poliol dalam sintesis Bio-PUNI-TG. Formula terbaik (FT 3) diperoleh dari kombinasi 15 g glioksal dan 18,52 g HMTA 80%, dengan validitas lebih baik dibandingkan FT 1 dan FT 2 terhadap respon kadar padatan, viskositas, dan kekuatan kohesi. Formula FT 3 juga menunjukkan kadar padatan, viskositas, dan kekuatan kohesi lebih tinggi dibandingkan FT 1 dan FT 2. Serat rami perlakuan menghasilkan peningkatan berat, ketahanan api, dan kuat tarik lebih tinggi dibandingkan kain rami, meskipun lebih rentan terhadap degradasi hidrolisis. Proses impregnasi dan pelapisan dengan flame retardant pada serat dan kain rami meningkatkan ketahanan api, meskipun masih di bawah kain tahan api komersial. Perlakuan impregnasi dengan FT 3 selama 90 menit dan dilapisis flame retardant menghasilkan karakteristik terbaik, sehingga berpotensi sebagai alternatif material tekstil fungsional berbasis bahan alam.

Using non-environmentally friendly synthetic fibers continues to dominate Indonesia's textile industry. Meanwhile, the domestic supply of natural fibers such as cotton remains insufficient. Developing alternative local fibers represents a strategic step toward self-sufficiency in textile raw materials. Ramie fiber (Boehmeria nivea (L.) Gaudich) is one of the most promising natural fibers due to its high cellulose content and good mechanical strength. However, its flammability and hygroscopic nature necessitate enhancement through impregnation with bio-based non-isocyanate polyurethane resin derived from glyoxalated tannin (Bio-NIPU-GT). This study aimed to analyze the characteristics of tannin extract, determine the optimal impregnation formula based on Bio-NIPU-GT, and evaluate the properties of impregnated and flame-retardant-coated ramie fibers and fabrics, in comparison with commercial flame-retardant textiles. Tannins were extracted from Acacia mangium bark using hot water maceration and subsequently characterized. The Bio-NIPU-GT resin was synthesized by mixing tannin extract with glyoxal, dimethyl carbonate, and hexamethylenetetramine (HMTA). Formulation optimization was carried out using Response Surface Methodology (RSM). The optimal formulation was analyzed for solid content, pH, functional groups, and rheological properties. Ramie fiber and fabric were then impregnated using the optimized formulation and coated with a flame retardant. Characterization of ramie fibers and fabrics before and after treatment included chemical structure analysis (FTIR, FE-SEM-EDX), mechanical properties (tensile strength), degradation resistance (hydrolysis test), and fire resistance (flammability test). The hot water maceration of A. mangium bark yielded a tannin extract with a 22.71% yield and a Stiasny number of 72.75%. The extract contained hydroxyl groups, confirming its potential as a polyol substitute in Bio-NIPU-GT synthesis. The best formulation (FT 3) was obtained using 15 g glyoxal and 18.52 g of 80% HMTA, showing superior validity to FT 1 and FT 2 regarding solid content, viscosity, and cohesive strength. FT 3 also exhibited higher solid content, viscosity, and cohesion than other formulations. Treated ramie fibers exhibited higher weight gain, flame resistance, and tensile strength than ramie fabrics, although they were more susceptible to hydrolytic degradation. The impregnation process, combined with flame-retardant coating, enhanced the flame resistance of both ramie fibers and fabrics, although the performance remained lower than that of commercial flame-retardant textiles. Impregnation with FT 3 for 90 minutes followed by flame-retardant coating provided the most favorable characteristics, indicating its potential as a sustainable alternative for functional natural-based textile materials.

Riset dan Inovasi untuk Indonesia Maju (RIIM), BRIN