Xylan-cellulose films: improvement of hydrophobicity, thermal and mechanical properties

Abstract

Xylan-rich hemicellulose from corn cob has been used for new material elaboration. Commercial cellulose was used as reinforcement in different percentages to improve properties of the films. Two types of composites were elaborated by solvent casting. Hydrophilic films, composed by bleached hemicellulose (BH), unmodified cellulose and glycerol as plasticizer, and hydrophobic films formed by acetylated bleached hemicellulose (BAH) and acetylated cellulose. The degree of substitution of BAH was 1.8 and acetylated cellulose presented a degree of substitution of 0.54. Thermal and mechanical properties of films were analyzed. A significant improvement was observed in the thermal behavior of hydrophobic films (Tmax ∼ 368 °C) respect to hydrophilic films (Tmax ∼ 300 °C). Although the addition of cellulose clearly increase the properties of both type of films, hydrophobic films (Young's modulus ∼ 2300 MPa, strength ∼ 44.1MPa, strain at break ∼ 5.7%) showed better mechanical properties than hydrophilic films (Young's modulus ∼ 3 MPa, strength ∼ 3.3 MPa, strain at break ∼ 5.3%).

Keywords: Acetylation; Cellulose; Mechanical properties; Thermal properties; Xylan.