Studies On The Prepartion And Properties Of Chitosan/Alginate Composite Modified Materials

Biopolymers from marine sources have been studied and utilized in pharmaceutical and biotechnological industry for many years. Alginate and chitosan are among the most versatile marine biopolymers. Chitosan, a copolymer ofβ-(1,4)-2-acetamido-2-deoxy-D-glucose andβ-(1,4)-2-amino-2-deoxy-D-glucose units, has attracted considerable interests in the field of wound dressing and tissue engineering due to its good biological activities, biocompatibility and biodegradability. Recent years, a great deal of research had been reported on chitosan's function in improving wound healing and tissue repairing。Alginates are a family of linear polysaccharides which contain varying amounts of 1,4-linkedβ-D-mannuronic acid and a-L-guluronic acid residues.The main contents in this thesis are as follows:1. Prepared the oxidation sodium alginate by sodium periodate oxidation, then cross-linked with the carboxymethyl chitosan(CMCS) and hydroxypropyl chitosan(HPCS) with the introduction of nano-silver and silver sulfadiazine to obtain hydrogels, Studied the impaction of the amount of sodium alginate oxide on the structure and property of hydrogels. The amount of sodium alginate oxide had no significant impact on the water content of the hydrogel; But showed significant impaction on the forming speed of the gels, the forming time decreased at first and then increased with the increasing of amount of sodium alginate. Using bovine serum albumin as a model drug to study the the sustained-release drug ability of the hydrogels in different pH, we found that the release rate of the hydrogels in acidic environment was more than neutral environment about 20 to 30%, and it decreased with the increasing of the amount of sodium alginate oxide. Result of antibacterial experiment showed that the introduction of the two silver antimicrobial agents have significantly improved the antibacterial ability of the hydrogels.2. Prepared sodium alginate oxide/D-carboxymethyl chitosan blend fibers by solution-spinning method with the introduction of nano silver, studying the impaction of the addition of D-carboxymethyl chitosan on the structure and property of fibers. FTIR and XRD showed that the interaction and compatibility of the two components in blend structures were strong and good. Tensile test showed that the dry fiber tensile strength of blend fibers achieve maximum value for 14.32cN/tex when the the content of D-carboxymethyl chitosan was 30wt%. The wet tensile strength of blend fibers decreased with the increasing of the content of D-carboxymethyl chitosan. When the content of D-carboxymethyl chitosan was 30wt%, the dry/wet breaking elongation reached 43.5% and 69.3% of the maximum. With the increasing of the content of D-carboxymethyl chitosan, water absorption of blend fibers improved significantly. The results of the antibacterial test of staphylococcus aureus showed that the fibers has strong antibacterial properties after the introduction of nano-silver.3. Polyvinyl alcohol sponge were prepared by the acetal reaction, and the introduction of chitin and chitosan to obtain a blend sponge system, study the impaction of the addition of chitin and chitosan on the structure and property. The results show that:Controlling the amount of chitin and chitosan could obviously improved the water absorption of the blend sponges, and also significantly impacted the mechanical properties of the blend sponges, the mechanical properties test showed that the introduction of chitin improved the tensile strength of the blend sponge, while the introduction of chitosan increased the breaking elongation. SEM photographs showed that the introduction of chitin and chitosan sponge enlarged the internal aperture size, meanwhile the impaction on the porous structure of the sponge are noticeable.The creative points in this thesis are as follows:(1) Prepared blend hygrogels that with efficient antibacterial property by cross-linking sodium alginate oxide and chitosan derivatives with the introduction of silver antimicrobial agent for the first time, use the sodium alginate oxide to replace the toxic cross-linking chemicals so that the hydrogels could be used iatrology area; (2) Prepared blend fibers by solution-spinning method with D-carboxymethyl chitosan and alginate solution for the first time, the introduction of D-carboxymethyl chitosan could obviously increase the WRV of the blend fibers, and the introduction of nano silver to obtained blend fibers that have efficient antibacterial property; (3) Polyvinyl alcohol cross-linked through acetal reaction that with chitin and chitosan to prepare new pattern composite sponge materials, these blend sponges have higher mechanics capability and lower cost than the sponges that obtained by lyophilization method.