2. Experimental
2.1. Materials
PLA (Bio-flexF 6510)was obtained from Fkur kunststoff GmbH (Siemensring 79, Germany) with a density of
1300 kg/m3, melting point of 150–170 C and molecular weight of 197,000 g/mol. PLA resins were dried in a vacuum
oven at 60 C for 24 h before use. CNF gel (3 wt%) was supplied by Nano Novin Polymer Co. (Sari, Iran). All other
reagents and solvents were of analytical grade and were used without further purification.
2.2. Cellulose acetylation
A mixture of acetic acid (25%) and sulfuric acid (3%) stirred at 70 C for 30 minwas prepared to activate CNF. The
acetylation of CNF was performed by adding 10 mL anhydride acetic and 50 mL acetic acid, and then stirring for 4 h
at 100 C. The acetylated CNF were then added to a solution of acetone: methanol (2:1, v:v) and chloroform to fulfill the
sequential phase transition of acetylated fibers to chloroform, which could then be adequately mixed with PLA.