Extraction Of Banana Nanocellulose And Research On Aerogel Dressin

With the depletion of petroleum resources,the development of new green and sustainable materials has become increasingly important.Banana fiber is a natural cellulose fiber with similar properties to hemp fiber.It is a new material extracted from discarded banana stalks.In my country alone,tens of millions of banana stalks are discarded every year,causing enviro nmental pollution and waste of resources.Therefore,the development and utilization of banana fiber has both economic and ecological benefits.In this project,the banana fiber was used as the raw material,and the nanocellulose was separated from the banana fiber by the combination of Soxhlet extraction,bleaching,degumming and ultrasonic grinding.Five kinds of aerogel dressings with nanocellulose concentrations of 0.2%,0.4%,0.6%,0.8% and 1%were prepared by ultrasonic and freeze-drying.The physicochemical structure was characterized by scanning electron microscopy and specific surface area.Physical and chemical properties such as swelling,water retention,porosity,water vapor permeability,mechanical properties,and antibacterial properties were tested.Aerogel dressings exhibit a porous network structure.With the increase of nanocellulose content,the specific surface area of the aerogel increased,the swelling and water retention properties improved,and the porosity gradually decreased.Increasing the concentration of nanocellulose can effectively reduce the loss of water vapor.The overall strength of the aerogel is lower,and the elongation at break decreases gradually.Aerogel dressings with different concentrations showed good antibacterial properties.In order to enhance the strength of the aerogel dressing and improve various physical and chemical properties,a modified aerogel dressing was prepared with the addition of konjac glucomannan(KGM)based on banana nanocellulose.The ratios of KGM to nanocellulose were 1/10,2/8,3/7,4/6,and 5/5,respectively.Physicochemical structure,performance,antibacterial and biocompatibility tests were carried out.The modified aerogel maintains a porous network structure.With the increase of KGM content,the swelling property of the aerogel dressing first increased and then decreased.When the ratio is 2/8,the swelling ratio increases from 2417% to 2981%.The water retention performance also showed a trend of first increasing and then decreasing.The porosity gradually decreased after adding KGM,but was still above 80%.The water vapor permeability first decreased and then increased with the addition of KGM.After modification,the breaking strength and elongation were both increased first and then decreased,and the highest breaking strength was increased to 3 times of the original.The modified aerogel dressing maintains good antibacterial properties,is a non-hemolytic material and has no cytotoxicity,and has great potential in wound dressing applications.