Preparation And Properties Of Carboxymethyl Cellulose/Chitosan Functional Composites

A pH-sensitive carboxymethyl cellulose/chitosan(CMC/CS)interpenetrating network(IPN)gel was prepared by using chitosan and carboxymethyl cellulose as raw materials,and epichlorohydrin was used as a crosslinking agent.The structure and properties of the composites were investigated by infrared spectroscopy(FT-IR),swelling behavior test and adsorption performance test.The FT-IR was used to analyze the cross-linking mechanism: epichlorohydrin loop was opened under acidic conditions.Then it crosslinked with hydroxyl groups on carboxymethyl cellulose and amino and hydroxyl groups on chitosan molecules.This reaction mechanism was in accordance with the mechanism of cross-linking reaction between epichlorohydrin and amino compound.The carboxymethyl cellulose/chitosan IPN gel could change the pH sensitivity and swelling reversibility of its swelling behavior according to the change of the external environment pH.And the ratio of CMC/CS had a significant effect on the swellability and pH responsiveness of the gel.The adsorption behavior of carboxymethyl cellulose/chitosan IPN gel on methylene blue dye was investigated by static adsorption test,and analyzed by Langmuir and Freundlich isotherm equations.The results showed that the adsorption capacity of the gel was significantly affected by the initial concentration,time and temperature of the dyes under the selected experimental conditions.Meanwhile,the adsorption reaction proceeded spontaneously,and the temperature rise is beneficial to the adsorption process.In this paper,carboxymethyl cellulose / chitosan composite medical sponges with a function of monitoring the pH of the wound environment were successfully prepared by freezing-drying technology.The effects of different ratios of carboxymethyl cellulose and chitosan powder on the swelling ratio,porosity,moisture permeability,water retention and compressive strength of the sponge were studied.The structure of the composite porous material was characterized by scanning electron microscopy(SEM).The pH environment monitoring performance of the composite sponges dyed with anthocyanin was characterized by datacolor spectrophotometer.The antibacterial properties of the composite sponge were investigated by antibacterial experiments.The results showed that the content of chitosan powder had a significant effect on the physical properties of the composite sponge.As the content of chitosan powder increased,the swelling performance and water retention capacity of the composite sponge decreased slightly,but the porosity,moisture permeability and compression resistance and antibacterial properties improved significantly.The SEM results showed that the internal structure of the composite sponge was a lamellar porous structure.The results of the pH responsiveness test showed that the anthocyanin-coated composite sponge responded quickly as the solutions pH values varied from 4 to 8.The color changed from blue-violet to green as the pH increased,and this color change was easy to distinguish.The final results showed that the carboxymethyl cellulose/chitosan powder composite sponge had excellent water absorption and gas permeability Furthermore,carboxymethyl cellulose /chitosan composite sponges had certain skin pH environment monitoring ability and excellent antibacterial performance.It is expected that the anthocyanin dyed carboxymethyl cellulose/chitosan sponges have great potential for wound healing monitor.