| The wood of Phyllostachys pubescens was selected as study materials in this paper.The bamboo powder was treated under pretreatment methods of dioxane and sodium hydroxide before being dissolved directly by ionic liquids.And then the regenerated films were obtained by coagulating of distilled water.Effects of different pretreatment conditions on performance and strucutre of bamboo and regenerated film were explored in the study.Bamboo powder was mixed with chitosan,titanium dioxide and zinc oxide at a certain proportion,then dissolved in ionic liquids,and cast into three blend membranes.Regeneration blend membranes were compared with regenerated film and studied their performance changes.The main conclusions are as follows:(1)The lignin content,the pentosan content and the ultraviolet absorption capacity of bamboo first reduced,and then increased with the increasing of dioxane concentration.Three of them were the lowest at the concentration of 90% in the pretreatment of dioxane.With the increase of pretreatment time,the lignin content,the pentosan content and the ultraviolet absorption intensity of the raw material gradually reduced,in addition.The relative crystallinity of bamboo increased and tended to be stable after pretreatment.(2)With the increase of sodium hydroxide concentration,the lignin content of bamboo powder reduced first,then increased slightly and became stable,and the pentosan content of bamboo powder gradually decreased.The type of cellulose crystal gradually turned from ? type to ? type in the process of pretreatment,and the half-peak width of bamboo increased after pretreatment.Bamboo was still had good performance of ultraviolet absorption after alkali treatment.(3)The tensile strength of regeneration film prepared on the condition of dioxane concentration of 90%,pretreatment time of 1.5 h was the maximum,and reached 146.60 MPa.Cellulose crystal type of regeneration film was ? type after the pretreatment of dioxane.When the concentration of dioxane was between 80%-95%,the half peak width of regeneration film was increased with the extension of processing time.The study indicated that interplanar crystal spacing of the regeneration film was increased with the increasing of pretreatment time.In the dynamic viscoelastic test,the ? relaxation of regeneration film gradually moving toward high temperature with the increase of concentration of dioxane.The movement of loss peak of regeneration film in 216-243? should be associated with the movement of amorphous cellulose and lignin molecular chain;With the increase ofconcentration of dioxane,temperature of DTG peak gradually decline after the first rebound;The regeneration films kept good ultraviolet absorption property.(4)With the increase of concentration of sodium hydroxide,the tensile strength of regeneration film was increased at first and decreased afterwards.The tensile strength of regeneration film prepared on the condition of sodium hydroxide concentration of 5%reached the peak value.The highest stress was 100.05 MPa.The crystal type of bamboo regeneration film was cellulose ? type,and the crystallization area structure of regeneration film was more compact through spend more time in the pretreatment of bamboo powder.The ultraviolet absorption ability of regeneration film prepared under the condition of 1% was the best in the pretreatment of sodium hydroxide.(5)Antibacterial test showed that the bamboo/chitosan blend membrane,bamboo/TiO2 membrane and bamboo/ZnO blend membrane had antimicrobial properties.The antimicrobial properties of blend membranes against e.coli were found as follows:bamboo/chitosan blend membrane > bamboo/TiO2 blend membrane > bamboo /ZnO blend membrane.The antimicrobial properties of three kinds of membranes against staphylococcus aureus were found as follows: bamboo/chitosan blend membrane >bamboo/ ZnO blend membrane > bamboo/TiO2 blend membrane.Mechanical property of the bamboo regeneration membrane was reduced,but the thermal stability was increased after blending. |
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