Gas barrier effect of 3-phenylpropionyl group on cellulose ester membranes

Abstract

This study was conducted to find the structural features of acyl groups that enhance both the thermoplasticity and gas barrier properties of cellulose esters (CEs). The morphology, thermomechanical properties, and the gas permeability of the membrane of a cellulose ester (CPhP) highly acylated with 3-phenylpropionyl (PhP) group were compared with the alkyl chain type (C2-C8) CE membranes. The glass transition temperature of the CPhP membrane was 48°C, which was lowest among the CE membranes. Although the gas permeability coefficient of the cellulose triacetate (CTA) and CPhP membranes was reversed as the temperature increased, the permeability coefficient of O2 and CO2 for the CPhP membrane at 25°C was 3.0 × 10−16 and 2.2 × 10−15 [mol mm−2 s−1 Pa−1], respectively, which was lower than the CTA membrane. Its thermoplasticity and gas barrier properties were simultaneously improved by the PhP group compared with the alkyl type acyl groups.

Keywords

• Cellulose esters
• 3-phenylpropionyl group
• Gas barrier
• Thermoplasticity
• Bulky substituent
• Aromatic interaction