Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Jan 6;27(2):331.
doi: 10.3390/molecules27020331.

Morphology, Mechanical, and Water Barrier Properties of Carboxymethyl Rice Starch Films: Sodium Hydroxide Effect

Pornchai Rachtanapun  1   2   3 , Sarinthip Thanakkasaranee  1   2   3 , Rafael A Auras  4 , Nareekan Chaiwong  1   5 , Kittisak Jantanasakulwong  1   2   3 , Pensak Jantrawut  2   6 , Yuthana Phimolsiripol  1   2 , Phisit Seesuriyachan  1   2 , Noppol Leksawasdi  1   2 , Thanongsak Chaiyaso  1   2 , Sarana Rose Somman  2   7 , Warintorn Ruksiriwanich  2   6 , Warinporn Klunklin  1 , Alissara Reungsang  8   9   10 , Thi Minh Phuong Ngo  11
Affiliations

Morphology, Mechanical, and Water Barrier Properties of Carboxymethyl Rice Starch Films: Sodium Hydroxide Effect

Pornchai Rachtanapun et al. Molecules. .

Abstract

Carboxymethyl rice starch films were prepared from carboxymethyl rice starch (CMSr) treated with sodium hydroxide (NaOH) at 10-50% w/v. The objective of this research was to determine the effect of NaOH concentrations on morphology, mechanical properties, and water barrier properties of the CMSr films. The degree of substitution (DS) and morphology of native rice starch and CMSr powders were examined. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were used to investigate the chemical structure, crystallinity, and thermal properties of the CMSr films. As the NaOH concentrations increased, the DS of CMSr powders increased, which affected the morphology of CMSr powders; a polyhedral shape of the native rice starch was deformed. In addition, the increase in NaOH concentrations of the synthesis of CMSr resulted in an increase in water solubility, elongation at break, and water vapor permeability (WVP) of CMSr films. On the other hand, the water contact angle, melting temperature, and the tensile strength of the CMSr films decreased with increasing NaOH concentrations. However, the tensile strength of the CMSr films was relatively low. Therefore, such a property needs to be improved and the application of the developed films should be investigated in the future work.

Keywords: NaOH; mechanical properties; morphology; solubility; water vapor permeability.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
The SEM micrographs of (a) rice starch powder, and CMSr powders synthesized with (b) 10%, (c) 20%, (d) 30%, (e) 40%, (f) 50%, and (g) 60% NaOH concentrations at 1000× followed by (A) rice starch film, and CMSr film synthesized with (B) 10%, (C) 20%, (D) 30%, (E) 40%, (F) 50%, and (G) 60% NaOH concentrations at 5000×.
Figure 1
Figure 1
The SEM micrographs of (a) rice starch powder, and CMSr powders synthesized with (b) 10%, (c) 20%, (d) 30%, (e) 40%, (f) 50%, and (g) 60% NaOH concentrations at 1000× followed by (A) rice starch film, and CMSr film synthesized with (B) 10%, (C) 20%, (D) 30%, (E) 40%, (F) 50%, and (G) 60% NaOH concentrations at 5000×.
Figure 2
Figure 2
FT-IR spectra of rice starch film and CMSr films synthesized with 10%, 20%, 30%, 40%, and 50% concentrations.
Figure 3
Figure 3
The SEM micrographs of (a) rice starch film, and CMSr film synthesized with (b) 10%, (c) 20%, (d) 30%, (e) 40%, and (f) 50% NaOH concentrations at 1000× followed by the cross-section micrographs of (A) rice starch film, and CMSr film synthesized with (B) 10%, (C) 20%, (D) 30%, (E) 40%, and (F) 50% NaOH concentrations at 2000×.
Figure 3
Figure 3
The SEM micrographs of (a) rice starch film, and CMSr film synthesized with (b) 10%, (c) 20%, (d) 30%, (e) 40%, and (f) 50% NaOH concentrations at 1000× followed by the cross-section micrographs of (A) rice starch film, and CMSr film synthesized with (B) 10%, (C) 20%, (D) 30%, (E) 40%, and (F) 50% NaOH concentrations at 2000×.
Figure 4
Figure 4
XRD patterns of native rice starch film and CMSr films synthesized with 10%, 20%, 30%, 40%, and 50% NaOH concentrations.
Figure 5
Figure 5
DSC thermograms of native rice starch film and CMSr films synthesized with 10%, 20%, 30%, 40%, and 50% NaOH concentrations.
Figure 6
Figure 6
The effect of %SM on native rice starch film and CMSr films synthesized with 10%, 20%, 30%, 40%, and 50% NaOH concentrations. Different letters (a, b, c, d, e) indicate significant differences between CMSr films synthesized with various NaOH concentrations.
Figure 7
Figure 7
The dynamic water contact angle of %SM on native rice starch film and CMSr films synthesized with 10%, 20%, 30%, 40%, and 50% NaOH concentrations with time (0–50 s).
Figure 8
Figure 8
The effect of water vapor permeability (WVP) on CMSr films synthesized with 10%, 20%, 30%, 40%, and 50% NaOH concentrations. Different letters (a, b, c, d, e) indicate significant differences between CMSr films synthesized with various NaOH concentrations.
Scheme 1
Scheme 1
Synthesis of carboxymethyl starch (CMS) from rice starch.
See this image and copyright information in PMC

References

    1. Pooresmaeil M., Namazi H. Developments on carboxymethyl starch-based smart systems as promising drug carriers: A review. Carbohydr. Polym. 2021;258:117654. doi: 10.1016/j.carbpol.2021.117654. - DOI - PubMed
    1. Wilpiszewska K., Antosik A.K., Schmidt B., Janik J., Rokicka J. Hydrophilic Films based on carboxymethylated derivatives of starch and cellulose. Polymers. 2020;12:2447. doi: 10.3390/polym12112447. - DOI - PMC - PubMed
    1. Spychaj T., Wilpiszewska K., Zdanowicz M. Medium and high substituted carboxymethyl starch: Synthesis, characterization and application. Starch-Stärke. 2013;65:22–33. doi: 10.1002/star.201200159. - DOI
    1. Stojanović Ž., Jeremić K., Jovanović S., Lechner M.D. A comparison of some methods for the determination of the degree of substitution of carboxymethyl starch. Starch-Stärke. 2005;57:79–83. doi: 10.1002/star.200400342. - DOI
    1. Li S.F., Mujyambere J.M.V., Liu M. Synthesis of carboxymethyl starch with high degree of substitution by a modified dry process. Adv. Mat. Res. 2011;233:306–310. doi: 10.4028/www.scientific.net/AMR.233-235.306. - DOI