Effect of Glycerol Concentrations on the Characteristics of Cellulose Films from Cattail (Typha angustifolia L.) Flowers

Abstract

Plastic waste has become a big problem for the environment globally. Biodegradable polymers are a potential replacement for plastics that can have a positive outcome both environmentally and economically. In this work, we used acid hydrolysis and alkaline treatment to extract cellulose fibers from cattails. The obtained cellulose was used as a substrate for the fabrication of cellulose film using a casting technique on plastic plates. Different concentrations of the plasticizer, glycerol, were used to prepare films for comparison, and its effects on the film's characteristics were observed. The morphology, chemical structure, and thermal stability of the cattail cellulose (CTC) films were studied using techniques such as scanning electron microscopy (SEM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and thermogravimetric analysis (TGA), respectively. Measurements of transparency, moisture content (MC), water solubility (MS), and water contact angle (WCA) were also performed. Introducing glycerol into the films increased the transparency, MC, and WS values, as well as the gap width between film textures. However, it resulted in a decrease in the WCA of the films, showing that the hydrophilicity of the films is increased by the addition of glycerol. The interaction between the functional groups of cellulose and glycerol was established from the ATR-FTIR and XRD data. The obtained results indicated that glycerol affected the thermal stability and the degree of crystallinity of the produced films. Accordingly, the hydrophilicity of the cellulose film was increased by increasing the glycerol content; therefore, cattail cellulose films can be used as a biodegradable alternative to plastic in the future.

Keywords: casting technique; cattail; cellulose; film; hydrophilicity.

Scheme 1

An example of the processing used to create cattail cellulose films.

Figure 1

Macroscopic aspect of native CTC film (A) and CTC with 1.38% (B), 2.78% (C), and 4.14% (v/v) (D) glycerol. Note diameter of the plate is 9 cm and scale bars are 3 cm.

Figure 2

SEM micrographs of CTC films without (a) and with different glycerol contents of 1.38% (b), 2.78% (c) and 4.14% (v/v) (d); imaging of the cross-section (I), the top surface (II), and the side attached to petri dishes (III) with 3000× magnification.

Figure 3

ATR-FTIR spectra of native cellulose (a) and CTC films with 1.38 (b), 2.78 (c), and 4.14% (d) (v/v) glycerol, respectively.

Figure 4

TG thermograms of CTC films without (d) and with different glycerol contents; 1.38% (b), 2.78% (c) and 4.14% (w/v) (a).

Figure 5

DTG curves of CTC films without (a) and with different glycerol contents; 1.38% (b), 2.78% (c) and 4.14% (w/v) (d).

Figure 6

XRD patterns for CTC film without (a) and with different glycerol contents; 1.38% (b), 2.78% (c) and 4.14% (d) (w/v).