海藻酸钠/聚丙烯酰胺复合水凝胶的壳聚糖增韧OA北大核心CSTPCD

A double network hydrogel was constructed by using natural polysaccharide sodium alginate and acrylamide as monomers,and chitosan was introduced to enhance the mechanical toughness of the hydrogel.The morphology,net-work crosslinking structure,and thermal properties of the as-prepared hydrogel were characterized by using scanning elec-tron microscopy,infrared spectroscopy,X-ray diffraction,and synchronous thermal analysis,and its crosslinking mecha-nism was analyzed.The results indicated that the toughness of the hydrogel was improved with an increase in the chito-san content.The increase of toughness at a low chitosan content was caused by the increase of elongation ability,where-as its increase at a high chitosan content it was caused by the simultaneous increase of strength and elongation.The toughness value of the hydrogel with 10 wt%chitosan reached 2.50×105 kJ/m3,which was significantly higher than the hydrogel containing 5 and 7.5 wt%chitosan.The elastic recovery rate of the hydrogel decreased with an increase in the set elongation rate during the constant elongation cycle stretching,and it was higher than 98%at set elongation of 25%,but only higher than 90%at set elongation of 200%.The hydrogel with 10%chitosan exhibited the best elastic-ity with a strong fracture stress of 0.249 MPa and fracture elongation of 1 635.65%,and it presented an excellent recov-ery ability at a constant elongation cycle of 200%or less.This study can provide a solution for the toughening of hydro-gels.