Sintesis dan Aplikasi Nanolignin Phosphorus Sebagai Filler Tahan Api Perekat Urea Formaldehida Kayu Lapis

Abstract

Modifikasi lignin dengan P2O5 dan transformasi ke ukuran nano menghasilkan material dengan luas permukaan lebih besar, ikatan polimer lebih kuat, dan distribusi merata yang meningkatkan sifat mekanis, serta stabilitas termal. Nanolignin terfosforilasi berpotensi sebagai aditif tahan api pembentuk lapisan arang dan scavenger pengurang emisi formaldehida. Penelitian ini bertujuan untuk menganalisis kondisi sintesis optimal nanolignin Eucalyptus sp. termodifikasi fosfor pentoksida, karakteristik perekat UF yang dimodifikasi dengan nanolignin terfosforilasi, dan sifat kayu lapis yang dihasilkan termasuk ketahanan api dan emisi formaldehida. Lignin terfosforilasi disintesis menjadi nanolignin terfosforilasi dan diaplikasikan sebagai filler aditif tahan api rendah emisis dengan perekat UF pada kayu lapis berbahan dasar kayu Jabon. Lignin terfosforilasi dan lignosulfonat terfosforilasi dianalisis berat ekuivalen, PyGCMS, dan NMR. Nanolignin terfosforilasi dikarakterisasi ukuran partikel, zeta potensial, FTIR, dan FE-SEM. Karakter perekat UF dianalisis kadar padatan, pH, densitas, gel time, rheometer, emisi formaldehida, FTIR, XRD, TGA, DSC, TEM, dan mikroskop. Kayu lapis UFNLP dikarakterisasi fisis (kerapatan, kadar air, dan delaminasi), dan mekanis (keteguhan rekat dan kerusakan kayu). Karakteristik lignin terfosforilasi yaitu berat ekuivalen 1674,44, rasio S/G 1,11, dan 13C NMR mengonfirmasi keberhasilan fosforilasi melalui peningkatan gugus alifatik primer-OH dan penurunan gugus metoksi yang mengindikasikan demetilasi parsial selama proses fosforilasi. Penelitian ini menghasilkan ukuran partikel nanolignin terfosforilasi 382,5 nm, zeta potensial -39,8 mV, berbentuk bulat oval, dan tidak terjadi perubahan gugus fungsi dengan intensitas puncak spektrum tinggi. Penambahan filler NLP membentuk ikatan hidrogen yang meningkatkan sifat dan kinerja perekat, termasuk peningkatan kadar padatan, densitas, viskositas, reaktivitas, kekuatan kohesi yang lebih besar, dan emisi formaldehida rendah. Penambahan NLP tidak mengubah gugus fungsi perekat UF, tetapi menurunkan kristalinitas dan membentuk struktur morfologi dengan partikel bulat kecil dan terdispersi merata. Perekat UFNLP memiliki distribusi permukaan paling homogen, ukuran droplet lebih kecil, dan penyebaran merata dibandingkan dengan formulasi lain. Sifat termal perekat UFNLP memiliki persen residu pembakaran dan nilai Tg yang tinggi. Kayu lapis UFNLP memiliki kerapatan tinggi, kadar air rendah, keteguhan rekat dan kerusakan kayu optimal, namun delaminasi belum memenuhi standar JAS No. 233 2003. Ketahanan api kayu lapis UFNLP lebih tinggi dibandingkan dengan kontrol dan mencapai kriteria V-0 pada uji UL-94. Hasil uji torch gas kayu lapis UFNLP juga memiliki persen kehilangan berat rendah. Berdasarkan hal tersebut nanolignin terfosforilasi berpotensi sebagai filler aditif tahan api rendah emisi.

Modification of lignin with P2O5 and transformation to nano-sized produced material with greater surface area, stronger polymer bonds, and uniform distribution that improve mechanical properties and thermal stability. Phosphorylated nanolignin has the potential to serve as both a flame-retardant additive that forms a char layer and a formaldehyde emission scavenger. This research aimed to analyze the optimal synthesis conditions of Eucalyptus sp. nanolignin modified with phosphorus pentoxide, the characteristics of UF adhesives modified with phosphorylated pentoxide, and the properties of the resulting plywood, including fire resistance and formaldehyde emissions. Phosphorylated lignin was synthesized into phosphorylated nanolignin and applied as a flame-retardant additive filler with UF adhesive in plywood made from Jabon wood. Lignophosphorylated and phosphorylated lignosulfonate were further analyzed using equivalent weight, PyGCMS, and NMR. Phosphorylated nanolignin was characterized by particle size, zeta potential, FTIR, and FE-SEM. The characteristics of UF adhesive were analyzed using solid content, pH, density, gel time, rheometer, formaldehyde emission, FTIR, XRD, TGA, DSC, TEM, and microscopy. UFNLP plywood was characterized physically (density, moisture content, and delamination) and mechanically (bond strength and wood damage). Further characteristics of phosphorylated lignin include an equivalent weight of 1674.44, S/G ratios of 1.11, and 13C NMR, which confirms the success of phosphorylation through an increase in primary aliphatic -OH groups and a decrease in methoxy groups, indicating partial demethylation during the phosphorylation process. This research produced phosphorylated nanolignin with a particle size of 382.5 nm, a zeta potential of -39.8 mV, an oval spherical shape, and no change in functional groups, exhibiting high peak intensity in the spectrum. The addition of NLP filler induced hydrogen bonding reactions, which improved adhesive properties and performance, including increased solid content, density, viscosity, reactivity, and greater cohesive strength, as well as reduced formaldehyde emission. The addition of NLP did not alter the functional groups of the UF adhesive; however, it decreased crystallinity and formed a morphological structure with small, diffuse spherical particles that were dispersed uniformly. Microscopic observation of UFNLP adhesives showed the most homogeneous surface distribution, smaller droplet size, and uniform dispersion compared to other formulations. The thermal properties of UFNLP adhesives exhibited a high combustion residue percentage and a high Tg value. UFNLP plywood had a high density, low moisture content, and optimal bond strength, but the delamination has not yet met the JAS No. 233 2003 standard. The fire resistance of UFNLP plywood was higher than that of the control and achieved a value of V-0 rating in the UL-94 test. Torch gas test results also showed that UFNLP plywood had a low weight loss percentage. Based on these findings, phosphorylated nanolignin demonstrated potential as a low-emission flame-retardant additive filler.