N-(2-hydroxyl)-propyl-3-trimethylammonium chitosan chloride/carboxymethyl cellulose films filled with in-situ crystallized calcium carbonate

Abstract

The research and development of substitutes for petroleum-based plastics has become a hot topic. The N-(2-hydroxyl)-propyl-3-trimethylammonium chitosan chloride (HTCC, 10 wt%)/sodium carboxymethyl cellulose (CMC) films have showed enhanced mechanical properties, which also provide a potential substitute to petroleum-based plastics. In this paper, calcium carbonate was crystallized (cry-CaCO₃) in HTCC/CMC film-forming solutions, and the effects of the cry-CaCO₃ particles on HTCC/CMC film properties including microstructures, mechanical properties, thermal stability, whiteness, and wettability were characterized. An HTCC/CMC film with commercially available CaCO₃ (com-CaCO₃) was used as a control. The results showed that the cry-CaCO₃ promoted the homogeneous distribution of the HTCC/CMC matrix and significantly improved mechanical properties, but showed little effect on the thermal stability, whiteness and wettability of the films. To reveal the affecting mechanism of cry-CaCO₃ on HTCC/CMC film properties, the cry-CaCO₃ particles were isolated from film-forming solutions and characterized by scanning electron microscope (SEM), powder X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA) methods. The results showed that the HTCC/CMC matrix modulated spherical CaCO₃ particles, and the macromolecules were encapsulated in cry-CaCO₃ particles, decreasing their adhesion to the HTCC/CMC matrix while increasing their distribution in the HTCC/CMC matrix. The strong electrostatic, hydrogen bonding and flexible interaction between CMC and cry-CaCO₃ particles played a key role in improving the mechanical properties of HTCC/CMC films.

Keywords: Calcium carbonate; Carboxymethyl cellulose; Film property; N-(2-hydroxyl)-propyl-3-trimethylammonium chitosan chloride.