Kap u k ( Ceiba pentandra ) is a type of plant and is used as a filler for pillows, bolsters, mattresses and others. Kapok contains 53-55% cellulose which has the potential to be developed as a functional biomaterial and has a higher selling value to be developed into nitrocellulose. This study aims to evaluate the effect of nitric acid concentration (15%, 20%, and 25% v /v ) , temperature (5 ⁰ C, 10 ⁰ C, 15 ⁰ C, 20 ⁰ C, 25 ⁰ C, and 30 ⁰ C ) and reaction time ( 15, 30, 45, 60 minutes ) in kapok cellulose nitration process based on the concentration of substituted nitrogen . Characterization of cellulose resulting from the nitration process in the form of morphological structure, functional groups, crystal structure and resistance to temperature. Isolation of micro fiber /cellulose from kapok was carried out in two process steps, namely delignification and bleaching processes . Delignification was carried out using the alkaline hydrothermal method, kapok (K) (2 g) mixed with 5% NaOH (w/v) as much as 80 mL and put in T eflon S stainless A autoclave and the reaction took place at 121 ^o C for 2 hours.   Kapok was washed until the pH was neutral and dried in an oven at 100 °C for 4 hours. Bleaching process with 2 g of delignified cottonwood added with 30% H ₂ O ₂ in 108 mL and carried out in an autoclave at 121 °C for 1 hour. Then washed with distilled water until neutral pH and dried at 100 °C for 4 hours in the oven as kapok cellulose (SK). 5% SK (w/b), 15% (v /v) nitric acid, and 15% ( v /v) phosphoric acid mixed and stirred at 300 rpm for various temperature and reaction time. After the reaction , it is washed with distilled water until the pH is neutral. The SK solid was then filtered and put in hot water for 5 minutes. The residue was rinsed again with distilled water and 10% (w/v) sodium bicarbonate until the pH value was neutral and dried in an oven at 60 ⁰ C to constant weight and nitrocellulose (NS) was obtained.   Based on the best nitration results at a concentration of 20% nitric acid , reaction for 30 minutes at 10 ^oC with a degree of substitution (DS) value of 0.885 , a moisture content of 4.94% and a yield of 52.21%. The resulting material can later be directed as a functional biomaterial .

Key words : hydrothermal , kapok , nitration, nitrocellulose , cellulose.