posted on 2024-02-23, 21:04authored byDe-Fa Hou, Pei-Yao Li, Kai Zhang, Meng-Lei Li, Zi-Wei Feng, Cong Yan, Can Liu, Ming-Bo Yang
Fatty acid cellulose esters (FACE) are common cellulose-based
thermoplastics,
and their thermoplasticity is determined by both the contents and
the lengths of the side chains. Herein, various FACE were synthesized
by the ball-milling esterification of cellulose and fatty acyl chlorides
containing 10–18 carbons, and their structures and thermoplasticity
were thoroughly studied. The results showed that FACE with high degrees
of substitution (DS) and low melting flow temperatures (Tf) were achieved as the chain lengths of the fatty acyl
chlorides were reduced. In particular, a cellulose decanoate with
a DS of 1.85 and a Tf of 186 °C was
achieved by feeding 3 mol of decanoyl chloride per mole anhydroglucose
units of cellulose. However, cellulose stearate (DS = 1.53) synthesized
by the same protocols cannot melt even at 250 °C. More interestingly,
the fatty acyl chlorides with 10 and 12 carbons resulted in FACE with
superior toughness (elongation at break up to 94.4%). In contrast,
due to their potential crystallization of the fatty acyl groups with
14–18 carbons, the corresponding FACE showed higher tensile
strength and Young’s modulus than the others. This study provides
some theoretical basis for the mechanochemical synthesis of thermoplastic
FACE with designated properties.