Preparation And Property Of Cellulose Based Functional Material Based On ATRP Technology

The biomass resource the represented with cellulose,is the most abundant natural polymer resource on earth,which could be the substitutes for petroleum-based resources due to its many excellent properties.In order to alleviate the environmental crisis and resource crisis caused by the excessive use of petroleum-based resources,and give full play to the advantages of cellulose for different applications,cellulose grafting modification is needed.ATRP technology is one of the powerful methods of modification of cellulose,which can prepare cellulose co-polymer with well-defined structure.It is also suitable for different forms of cellulose.Based on this,this paper carries out the following work:(1)In a heterogeneous system,PDMAEMA polymer chain was grafted on the surface of CNC via ATRP.Then the brominated alkanes(C10-Br,C14-Br,C18-Br),as the quaternization reagent,were installed on the amine groups of polymer chain.The quaternized modified CNC(CNC-PDMAEMA-C10,CNC-PDMAEMA-C14,CNC-PDMAEMA-C18) was prepared successfully.The results show that the hydrophobicity of the quaternized modified CNC is significantly improved,and the order as follow:CNC-PDMAEMA-C10<CNC-PDMAEMA-C14<CNC-PDMAEMA-C18.The prepared CNC-PDMAEMA-Cn(n=10,14,18) showed good antibacterial properties against Escherichia coli and Staphylococcus aureus,and the antibacterial rates against Escherichia coli and Staphylococcus aureus were both greater than 98%.CNC-PDMAEMA-C10 has better antibacterial effect,which is related to the surface wettability of the quaternized modified CNC.The low surface wettability of the material with high hydrophobicity may limit the contact of the polymer antibacterial group to the bacterial cell plasma membrane,thereby affecting the antibacterial activity of the material.It was found that the antibacterial rate of the material against Staphylococcus aureus was slightly higher than that of Escherichia coli.(2)Firstly,CNC was grafted PDMAEMA polymer via ATRP.Then,the nanohybrid materials(CuSNPs@CNC-PDMAEMA) were prepared by in situ deposition of CuSNPs in modified CNC by chemical co-precipitation.A novel stable and cheap LSMP was prepared with PU and CuSNPs@CNC-PDMAEMA,which exhibited good light-induced shape memory,which was ascribed to the highly photothermal effect of CuSNPs.We found that the shape recovery ratio was 97.4% when the PU nanocomposite film containing 0.2wt.% CuSNPs@MCNC was irradiated by NIR for 21s.The ratio was still over 85.7% after five times of repeat test.(3)The modified MCC grafted PDMAEMA was synthesized via ATRP in homogeneous system.Then,the flake CuSNPs was prepared by hydrothermal method under assisting of modified MCC.CuSNPs and PU are combined to produce a novel nanocomposite film,which has photo-triggerable shape memory and photo-triggerable healing properties.The two properties are deeply related to the content of CuSNPs in the nanocomposite film.When the content of CuSNPs was 0.05wt%,the nanocomposite only exhibited undesirability shape memory property(Rr=78.6%).The healing efficiency of nanocomposite with higher content(0.1wt%) of CuSNPs was over 99% under irradiation by NIR for 60s,and Rr could up to 100%.The healed nanocomposite film retained its photo-triggered shape memory property with original mechanical strength.The photo healing and shape memory properties of nanocomposite films are independent of each other.(4)The modified CNC(CNC-PDMAPMA,CNC-PDMAEMA and CNC-PDEAEMA) were prepared by ATRP in MeOH/H₂O at room temperature.The modified CNC aqueous dispersion can effectively reduce the interfacial tension of TL/H₂O and HP/H₂O after bobbling N₂,and the improvement of interfacial tension of TL/H₂O by modified CNC is better than that of HP/H₂O.TL/H₂O Pickering emulsion and HP/H₂O Pickering emulsion prepared by 0.6wt.% modified CNC can be preserved for at least 15 days without phase separation.By injecting N₂ or CO₂ into the system,the emulsification/demulsification conversion of Pickering emulsion stabled by 0.6wt.% modified CNC can be easily and cleanly realized.(5)Wood-based aerogel was prepared by removing all lignin and portion hemicellulose in pH=4.6 NaClO₂/CH₃COOH.Azobenzene derivatives were grafted to wood aerogel by ATRP technology.The results show that wood aerogels and modified wood aerogels have good compression performance after 50 compression cycles.The hydrophobicity of the modified wood aerogel was also improved to 122°.The modified wood-based aerogel is irradiated by UV(365nm)/sunlight,and the color of material transfer reversibly between yellow and orange-red.