High Substitution Synthesis of Carboxymethyl Chitosan for Properties Improvement of Carboxymethyl Chitosan Films Depending on Particle Sizes.

Sarinthip Thanakkasaranee,Wirongrong Tongdeesoontorn,Noppol Leksawasdi,Yuthana Phimolsiripol,Parichat Thipchai,Winita Punyodom,Alissara Reungsang,Sarana Rose Sommano,Warintorn Ruksiriwanich,Phisit Seesuriyachan,Kittisak Jantanasakulwong,Thanongsak Chaiyaso,Pensak Jantrawut,Pornchai Rachtanapun,Thi Minh Phuong Ngo

doi:10.3390/molecules26196013

Abstract

This study investigated the effect of chitosan particle sizes on the properties of carboxymethyl chitosan (CMCh) powders and films. Chitosan powders with different particle sizes (75, 125, 250, 450 and 850 µm) were used to synthesize the CMCh powders. The yield, degree of substitution (DS), and water solubility of the CMCh powders were then determined. The CMCh films prepared with CMCh based on chitosan with different particle sizes were fabricated by a solution casting technique. The water solubility, mechanical properties, and water vapor transmission rate (WVTR) of the CMCh films were measured. As the chitosan particle size decreased, the yield, DS, and water solubility of the synthesized CMCh powders increased. The increase in water solubility was due to an increase in the polarity of the CMCh powder, from a higher conversion of chitosan into CMCh. In addition, the higher conversion of chitosan was also related to a higher surface area in the substitution reaction provided by chitosan powder with a smaller particle size. As the particle size of chitosan decreased, the tensile strength, elongation at break, and WVTR of the CMCh films increased. This study demonstrated that a greater improvement in water solubility of the CMCh powders and films can be achieved by using chitosan powder with a smaller size.

Highlights

Demands for the development of new functional materials with biocompatibility and biodegradability are continuously increasing, which has led to an increase in the utilization of biopolymers as compared to synthetic conventional polymers [1,2].Among biopolymers, chitosan is an attractive material, owing to its biocompatibility, antimicrobial activity, cheapness, and low toxicity
The observation of strong peak intensity in the vicinity of 1599 cm−1 might correspond to the vibration of the COO– group overlapped with the original N–H bond of chitosan, which might imply that there was some conversion of chitosan to carboxymethyl chitosan
The present study showed that the chitosan particle size strongly affected the chemical and physical properties of the synthesized carboxymethyl chitosan (CMCh) powders and the CMCh films

Summary

Introduction

Demands for the development of new functional materials with biocompatibility and biodegradability are continuously increasing, which has led to an increase in the utilization of biopolymers as compared to synthetic conventional polymers [1,2]. Chitosan is an attractive material, owing to its biocompatibility, antimicrobial activity, cheapness, and low toxicity. It has been widely used in the pharmaceutical industry (e.g., drug delivery carrier) [3,4], for biomedical applications (e.g., wound dressing) [5,6], the cosmetic industry (e.g., encapsulation of essential oils) [7], and the food packaging industry (e.g., antimicrobial film) [8]. An improvement of water solubility of chitosan is required prior to its application

Methods

Results

Conclusion