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Preparation and Properties of Cellulose Nanomaterials 被引量:20
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作者 Alain Dufresne 《Paper And Biomaterials》 2020年第3期1-13,共13页
Cellulose is the most abundant biomass material in nature and it is mainly extracted from natural or lignocellulosic fibers.After purification,cellulose fibers exhibit two interesting features for their further transf... Cellulose is the most abundant biomass material in nature and it is mainly extracted from natural or lignocellulosic fibers.After purification,cellulose fibers exhibit two interesting features for their further transformation into nanomaterials:a hierarchical and multi-level strcture,and a semicrystalline microstructure.Different forms of cellulose nanomaterials,resulting from a top-down deconstructing strategy(cellulose nanocrystals(CNCs),cellulose nanofibrils(CNFs))or bottom-up strategy(bacterial cellulose(BC))can be prepared.Multiple mechanical shearing actions applied to cellulosic fibers release more or less the nanofibrils individually.A controlled strong acid hydrolysis treatment can be applied to cellulosic fibers allowing dissolution of non-crystalline domains.Such cellulose nanomaterials have been the focus of an exponentially increasing number of works or reviews devoted to understand such materials and their applications.They have a high potential for an emerging industry.In the nanoscale,cellulose exhibits specific properties broadening the applications of this naturally occurring polymer.An overview of existing methods for the preparation of cellulose nanomaterials and their specific properties that outperform and contrast with cellulose in the microscale is proposed. 展开更多
关键词 CELLULOSE NANOMATERIAL nanocrystal nanofibril PREPARATION PROPERTIES
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Preparation and Performance of Salt Tolerance and Thermal Stability Cellulose Nanofibril Hydrogels and Their Application in Drilling Engineering 被引量:7
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作者 XiongLi Liu An Wang +7 位作者 ChunPing Wang JiaLei Qu YangBing Wen Bin Chen ZhongGuang Wang BinBin Wu ZhaoYang Yuan Bing Wei 《Paper And Biomaterials》 2019年第2期10-19,共10页
The poor salt tolerance,thermal stability,and environmental performance of petrochemicals can severely limit their applications in drilling engineering.In this study,cellulose nanofibril(CNF)hydrogels with improved sa... The poor salt tolerance,thermal stability,and environmental performance of petrochemicals can severely limit their applications in drilling engineering.In this study,cellulose nanofibril(CNF)hydrogels with improved salt tolerance and thermal stability were prepared,and their filtration performance was evaluated.The hydrogels were prepared through the simultaneous grafting of 2-acrylamido-2-methylpropane sulfonic acid(AMPS)and butyl acrylate(BA)onto the CNF surface through ceric ammoniumnitrate-induced radical polymerization.The modified and original CNF samples were characterized using Fourier Transform infrared spectroscopy(FT-IR)and rheological measurements.The FT-IR analysis results showed that both AMPS and BA were grafted onto the CNF backbone,affirming the successful preparation of the grafted CNFs.The rheological analysis results showed that the modified CNF hydrogels exhibited significantly improved salt tolerance,thermal stability,and“salt-thickening”effect.Moreover,the results of the fluid loss test showed that the modified CNF hydrogels exhibited a much better fluid loss control than the original CNF hydrogels.In addition,after adding 2%modified CNF hydrogels as a filtrate reducer in the drilling fluids prepared with a 6%combined salt solution,the filtrate loss was significantly reduced even after aging for 72 h at 160℃. 展开更多
关键词 CELLULOSE nanofibril hydrogel GRAFTING FILTRATE reducer drilling fluid
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Reinforcing Paper Strength by Dual Treatment of a Cationic Water-soluble Polymer and Cellulose Nanofibril 被引量:7
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作者 Aijiao Wang Lijun Wang +2 位作者 Jianmei Jiang Xianping Yao Wenyan Zhao 《Paper And Biomaterials》 2019年第4期31-36,共6页
Cellulose nanofibril(CNF)was used as the anionic component of two dual strengthening systems wherein polyamidopolyamine epichlorohydrin resin(PAE)or cationic starch(CS)was used as the cationic component.Their strength... Cellulose nanofibril(CNF)was used as the anionic component of two dual strengthening systems wherein polyamidopolyamine epichlorohydrin resin(PAE)or cationic starch(CS)was used as the cationic component.Their strengthening effects were investigated for lowbasis-weight(30 g/m2)paper composed of a mixture of fully bleached softwood and hardwood pulp in a 4:1 mass ratio.Using the PAE/CNF or CS/CNF dual system,it was generally easier to achieve higher wet and dry tensile strengths of paper compared to the paper using the single PAE or CS system.For example,the paper using the PAE(0.4%)/CNF(0.3%)dual system exhibited 89%higher wet tensile strength than the paper using the single PAE(0.4%)system,and the paper using CS(1.3%)/CNF(0.3%)dual treatment showed 21%higher dry strength than that using the single CS(1.3%)system.However,the PAE/CNF system only showed small improvement in the dry strength of paper(11%higher than that of paper using the single PAE system),so did the CS/NFC system on wet strength improvement(only 17%higher than that of paper using the single CS system). 展开更多
关键词 CELLULOSE nanofibril polyamidopolyamine EPICHLOROHYDRIN CATIONIC STARCH DUAL TREATMENT
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Application of Cellulose Nanofibril as a Wet-end Additive in Papermaking:A Brief Review 被引量:9
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作者 Guihua Yang Guangrui Ma +4 位作者 Ming He Xinxiang Ji Hye Jung Youn Hak Lae Lee Jiachuan Chen 《Paper And Biomaterials》 2020年第2期76-84,共9页
Recently,cellulose nanofibril(CNF)has emerged as a promising,sustainable reinforcement with outstanding potential in material science.Owing to the properties of CNF,it has been explored in food,cosmetic,and pharmaceut... Recently,cellulose nanofibril(CNF)has emerged as a promising,sustainable reinforcement with outstanding potential in material science.Owing to the properties of CNF,it has been explored in food,cosmetic,and pharmaceutical applications,as well as in industrial applications such as paints,drill muds,packaging,and papermaking.The application of CNF in papermaking is expected to be implemented in the near future to broaden the commercial market of cellulose.Numerous studies and patents have reported on the manufacturing,properties,and applications of nanocellulose.This present paper focuses on the recent progresses in the application of CNF as a wet-end additive in papermaking. 展开更多
关键词 CELLULOSE nanofibril PAPERMAKING wet-end ADDITIVE DEWATERING
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Flexible conductive Ag nanowire/cellulose nano?bril hybrid nanopaper for strain and temperature sensing applications 被引量:9
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作者 Rui Yin Shuaiyuan Yang +5 位作者 Qianming Li Shuaidi Zhang Hu Liu Jian Han Chuntai Liu Changyu Shen 《Science Bulletin》 SCIE EI CAS CSCD 2020年第11期899-908,M0003,共11页
With the rapid development of smart wearable devices, flexible and biodegradable sensors are in urgent needs. In this study, ‘‘green" electrically conductive Ag nanowire (Ag NW)/cellulose nanofiber (CNF) hybrid... With the rapid development of smart wearable devices, flexible and biodegradable sensors are in urgent needs. In this study, ‘‘green" electrically conductive Ag nanowire (Ag NW)/cellulose nanofiber (CNF) hybrid nanopaper was fabricated to prepare flexible sensors using the facial solution blending and vacuum filtration technique. The amphiphilic property of cellulose is beneficial for the homogeneous dispersion of Ag NW to construct effective electrically conductive networks. Two different types of strain sensors were designed to study their applications in strain sensing. One was the tensile strain sensor where the hybrid nanopaper was sandwiched between two thermoplastic polyurethane (TPU) films through hot compression, and special micro-crack structure was constructed through the pre-strain process to enhance the sensitivity. Interestingly, typical pre-strain dependent strain sensing behavior was observed due to different crack densities constructed under different pre-strains. As a result, it exhibited an ultralow detection limit as low as 0.2%, good reproducibility under different strains and excellent stability and durability during 500 cycles (1% strain, 0.5 mm/min). The other was the bending strain sensor where the hybrid nanopaper was adhered onto TPU film, showing stable and recoverable linearly sensing behavior towards two different bending modes (tension and compression). Importantly, the bending sensor displayed great potential for human motion and physiological signal detection. Furthermore, the hybrid nanopaper also exhibited stable and reproducible negative temperature sensing behavior when it was served as a temperature sensor. This study provides a guideline for fabricating flexible and biodegradable sensors. 展开更多
关键词 Ag nanowire Cellulose nanofibril NANOPAPER STRAIN Temperature sensor
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纳米纤维素的最新制备进展Ⅰ.化学法 被引量:9
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作者 张燕 张铭涛 +4 位作者 沈晓飞 王震宇 文海云 王慧庆 卢芸 《纤维素科学与技术》 CAS CSCD 2020年第3期49-58,共10页
综述了近三年来国内外纳米纤维素制备研究的新兴化学方法和最新进展,重点举例阐述可回收的有机酸水解法、酸蒸气法、Pickering乳液法、过硫酸铵氧化法、芬顿法、微波辅助法、离子液体法等不同制备方法,并围绕各种方法的作用机理、操作... 综述了近三年来国内外纳米纤维素制备研究的新兴化学方法和最新进展,重点举例阐述可回收的有机酸水解法、酸蒸气法、Pickering乳液法、过硫酸铵氧化法、芬顿法、微波辅助法、离子液体法等不同制备方法,并围绕各种方法的作用机理、操作工艺、产物结构等讨论了各种制备方法的优缺点。侧重介绍化学法,第一突出新方法的出现,第二突出由传统制备方法拓展到多种生物质资源,将在续篇“纳米纤维素的最新制备进展Ⅱ”中详细介绍机械法,旨在促进农林纳米纤维素资源的绿色开发。 展开更多
关键词 纳米纤维素 制备 纳米纤丝 纤维素纳米晶 纳米晶须
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破译pH值和金属离子编程的家蚕纺丝机制
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作者 宋凯 王叶菁 +4 位作者 董文杰 李珍珍 夏庆友 朱平 何华伟 《Science Bulletin》 SCIE EI CAS CSCD 2024年第6期792-802,共11页
Silk is one of the toughest fibrous materials known despite spun at ambient temperature and pressure with water as a solvent.It is a great challenge to reproduce high-performance artificial fibers comparable to natura... Silk is one of the toughest fibrous materials known despite spun at ambient temperature and pressure with water as a solvent.It is a great challenge to reproduce high-performance artificial fibers comparable to natural silk by bionic for the incomplete understanding of silkworm spinning in vivo.Here,we found that amphipol and digitonin stabilized the structure of natural silk fibroin(NSF)by a large-scale screening in vitro,and then studied the close-to-native ultrastructure and hierarchical assembly of NSF in the silk gland lumen.Our study showed that NSF formed reversible flexible nanofibrils mainly composed of random coils with a sedimentation coefficient of 5.8 S and a diameter of about 4 nm,rather than a micellar or rod-like structure assembled by the aggregation of globular NSF molecules.Metal ions were required for NSF nanofibril formation.The successive p H decrease from posterior silk gland(PSG)to anterior silk gland(ASG)resulted in a gradual increase in NSF hydrophobicity,thus inducing the sol-gelation transition of NSF nanofibrils.NSF nanofibrils were randomly dispersed from PSG to ASG-1,and self-assembled into anisotropic herringbone patterns at ASG-2 near the spinneret ready for silkworm spinning.Our findings reveal the controlled self-assembly mechanism of the multi-scale hierarchical architecture of NSF from nanofibrils to herringbone patterns programmed by metal ions and p H gradient,which provides novel insights into the spinning mechanism of silk-secreting animals and bioinspired design of high-performance fibers. 展开更多
关键词 Natural silk fibroin nanofibril SELF-ASSEMBLY SILKWORM CRYO-EM
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β-乳球蛋白纤维化过程中的界面及乳化性质 被引量:6
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作者 黄颖 高志明 +3 位作者 吴彬娴 林展拓 赵俊俊 方亚鹏 《食品科学》 EI CAS CSCD 北大核心 2018年第6期20-25,共6页
依据蛋白质在酸热环境下能通过自组装形成纤维状聚集体的特性,首先利用荧光强度、透射电子显微镜等手段对β-乳球蛋白纳米纤维的形成过程进行表征,再通过界面流变仪对各阶段产物的界面吸附及界面黏弹模量进行分析,并在此基础上对其乳化... 依据蛋白质在酸热环境下能通过自组装形成纤维状聚集体的特性,首先利用荧光强度、透射电子显微镜等手段对β-乳球蛋白纳米纤维的形成过程进行表征,再通过界面流变仪对各阶段产物的界面吸附及界面黏弹模量进行分析,并在此基础上对其乳化行为进行研究。结果表明:纤维化过程中不同阶段产物具有不同的界面及乳化行为。随着纤维化转变进行,混合体系的界面吸附能力以及界面黏弹模量逐渐增加。不同阶段产物能形成粒径在8.5~10.5μm之间的稳定乳液,且乳化能力随着纤维化转变而增强,但过度纤维化转变不利于蛋白质的乳化稳定性。 展开更多
关键词 Β-乳球蛋白 纳米纤维 界面性质 乳化性
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Injectable Nanorobot-Hydrogel Superstructure for Hemostasis and Anticancer Therapy of Spinal Metastasis
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作者 Qing Chen Miao Yan +10 位作者 Annan Hu Bing Liang Hongwei Lu Lei Zhou Yiqun Ma Chao Jia Dihan Su Biao Kong Wei Hong Libo Jiang Jian Dong 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第12期59-80,共22页
Surgery remains the standard treatment for spinal metastasis.However,uncontrolled intraoperative bleeding poses a significant challenge for adequate surgical resection and compromises surgical outcomes.In this study,w... Surgery remains the standard treatment for spinal metastasis.However,uncontrolled intraoperative bleeding poses a significant challenge for adequate surgical resection and compromises surgical outcomes.In this study,we develop a thrombin(Thr)-loaded nanorobothydrogel hybrid superstructure by incorporating nanorobots into regenerated silk fibroin nanofibril hydrogels.This superstructure with superior thixotropic properties is injected percutaneously and dispersed into the spinal metastasis of hepatocellular carcinoma(HCC)with easy bleeding characteristics,before spinal surgery in a mouse model.Under near-infrared irradiation,the self-motile nanorobots penetrate into the deep spinal tumor,releasing Thr in a controlled manner.Thr-induced thrombosis effectively blocks the tumor vasculature and reduces bleeding,inhibiting tumor growth and postoperative recurrence with Au nanorod-mediated photothermal therapy.Our minimally invasive treatment platform provides a novel preoperative therapeutic strategy for HCC spinal metastasis effectively controlling intraoperative bleeding and tumor growth,with potentially reduced surgical complications and enhanced operative outcomes. 展开更多
关键词 Silk fibroin nanofibril hydrogels Nanorobots THROMBIN Spinal metastasis
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Silk nanofibril as nanobinder for preparing COF nanosheet-based proton exchange membrane 被引量:1
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作者 Ping Li Ningxin Zhang +1 位作者 Xuan Li Shaokun Tang 《Green Energy & Environment》 SCIE EI CAS CSCD 2023年第3期915-926,共12页
Two-dimensional covalent organic framework nanosheets(CONs)with ultrathin thickness and porous crystalline nature show substantial potential as novel membrane materials.However,bringing CONs materials into flexible me... Two-dimensional covalent organic framework nanosheets(CONs)with ultrathin thickness and porous crystalline nature show substantial potential as novel membrane materials.However,bringing CONs materials into flexible membrane form is a monumental challenge due to the limitation of weak interactions among CONs.Herein,one-dimensional silk nanofibrils(SNFs)from silkworm cocoon are designed as the nanobinder to link sulfonated CON(SCON)into robust SCON-based membrane through vacuum-filtration method.Ultrathin and large lateral-sized SCONs are synthesized via bottom-up interface-confined synthesis approach.Benefiting from high length-diameter ratio of SNF and rich functional groups in both SNF and SCON,two-dimensional(2D)SCONs are effectively connected together by physical entanglement and strong H-bond interactions.The resultant SCON/SNF membrane displays dense structure,high mechanical integrity and good stability.Importantly,the rigid porous nanochannels of SCON,high-concentration-SO3H groups insides the pores and H-bonds at SCON-SNF interfaces impart SCON/SNF membrane high-rate proton transfer pathways.Consequently,a superior proton conductivity of 365 mS cm^(-1)is achieved at 80C and 100%RH by SCON/SNF membrane.This work offers a promising approach for connecting 2D CON materials into flexible membrane as high-performance solid electrolyte for hydrogen fuel cell and may be applied in membrane-related other fields. 展开更多
关键词 Covalent organic framework nanosheet Silk nanofibril Membrane Proton conductivity Fuel cell
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纳米纤维素的最新制备研究Ⅱ.机械法 被引量:4
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作者 张燕 左盼盼 +4 位作者 王超君 元佳丽 徐天和 王慧庆 卢芸 《纤维素科学与技术》 CAS CSCD 2020年第4期56-62,共7页
“纳米纤维素的最新制备进展Ⅰ”的续篇Ⅱ,重点阐述了高压均质法、球磨法、微波辅助法、亚临界水解法、双螺杆挤出法等机械法,综合分析了纳米纤维素各种机械制备方法的应用条件和优缺点。其中球磨法结合非极性溶剂可获得亲油晶面暴露的... “纳米纤维素的最新制备进展Ⅰ”的续篇Ⅱ,重点阐述了高压均质法、球磨法、微波辅助法、亚临界水解法、双螺杆挤出法等机械法,综合分析了纳米纤维素各种机械制备方法的应用条件和优缺点。其中球磨法结合非极性溶剂可获得亲油晶面暴露的新型纤维素纳米材料,亚临界水解法绿色环保且成本较低,双螺杆挤出法作为一种新的机械处理法相比于传统机械法能耗更低。更进一步地,介绍了纳米纤维素在国内外最新的产业化状况,旨在促进农林纳米纤维素资源的绿色、高效、低成本、可持续开发和高值利用。 展开更多
关键词 纳米纤维素 制备 纳米纤丝 纤维素纳米晶 纳米晶须
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Cellulose nanofibril matrix drives the dynamic formation of spheroids
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作者 Yi LU Guo LI +1 位作者 Yeqiu LI Yuan YAO 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2023年第10期922-934,共13页
Multicellular spheroids,which mimic the natural organ counterparts,allow the prospect of drug screening and regenerative medicine.However,their application is hampered by low processing efficiency or limited scale.Thi... Multicellular spheroids,which mimic the natural organ counterparts,allow the prospect of drug screening and regenerative medicine.However,their application is hampered by low processing efficiency or limited scale.This study introduces an efficient method to drive rapid multicellular spheroid formation by a cellulose nanofibril matrix.This matrix enables the facilitated growth of spheroids(within 48 h)through multiple cell assembly into size-controllable aggregates with well-organized physiological microstructure.The efficiency,dimension,and conformation of the as-formed spheroids depend on the concentration of extracellular nanofibrils,the number of assembled cells,and the heterogeneity of cell types.The above strategy allows the robust formation mechanism of compacted tumoroids and hepatocyte spheroids. 展开更多
关键词 CELLULOSE nanofibril MATRIX SELF-ASSEMBLY SPHEROID
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Hierarchically porous cellulose nanofibril aerogel decorated with polypyrrole and nickel-cobalt layered double hydroxide for high-performance nonenzymatic glucose sensors
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作者 Xuanze Li Wenyan Tian +5 位作者 Caichao Wan Sulai Liu Xinyi Liu Jiahui Su Huayun Chai Yiqiang Wu 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2023年第10期1593-1607,共15页
With increasing emphasis on green chemistry,biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials.Herein,a new pore-rich cellulose nanofibril aer... With increasing emphasis on green chemistry,biomass-based materials have attracted increased attention regarding the development of highly efficient functional materials.Herein,a new pore-rich cellulose nanofibril aerogel is utilized as a substrate to integrate highly conductive polypyrrole and active nanoflower-like nickel-cobalt layered double hydroxide through in situ chemical polymerization and electrodeposition.This ternary composite can act as an effective self-supported electrode for the electrocatalytic oxidation of glucose.With the synergistic effect of three heterogeneous components,the electrode achieves outstanding glucose sensing performance,including a high sensitivity(851.4μA·mmol^(−1)·L·cm^(−2)),a short response time(2.2 s),a wide linear range(two stages:0.001−8.145 and 8.145−35.500 mmol·L^(−1)),strong immunity to interference,outstanding intraelectrode and interelectrode reproducibility,a favorable toxicity resistance(Cl^(‒)),and a good long-term stability(maintaining 86.0%of the original value after 30 d).These data are superior to those of some traditional glucose sensors using nonbiomass substrates.When determining the blood glucose level of a human serum,this electrode realizes a high recovery rate of 97.07%–98.89%,validating the potential for highperformance blood glucose sensing. 展开更多
关键词 cellulose nanofibril AEROGEL nickel-cobalt layered double hydroxide POLYPYRROLE nonenzymatic glucose sensor
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海藻纤维素气凝胶:从绿潮到新材料 被引量:3
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作者 赵卫 卢芸 +6 位作者 欧阳欢 闫小美 潘若才 杨东江 佘希林 李坚 夏延致 《科技导报》 CAS CSCD 北大核心 2014年第4期34-39,共6页
系统讨论了绿潮浒苔的独特结构和功能特性,旨在制备纳米纤丝化的海藻纤维素和高比表面积的气凝胶材料,并为浒苔的高价值应用提供新的思路。将绿潮肇事种浒苔化学纯化脱去多糖、蛋白、脂肪后,用圆盘胶磨(20000 r/min,20 min)进行纳米纤丝... 系统讨论了绿潮浒苔的独特结构和功能特性,旨在制备纳米纤丝化的海藻纤维素和高比表面积的气凝胶材料,并为浒苔的高价值应用提供新的思路。将绿潮肇事种浒苔化学纯化脱去多糖、蛋白、脂肪后,用圆盘胶磨(20000 r/min,20 min)进行纳米纤丝化,制备出均一直径(大约40 nm)和高长径比的Iα纳米纤丝化纤维素。经由叔丁醇置换和冷冻干燥后可以制备出高比表面积(277 cm2/g)、密度为23 mg/cm3的柔性纳米纤丝化纤维素气凝胶。所有这些结果通过扫描电镜(SEM)、红外光谱仪(FTIR)、X射线衍射仪(XRD)进行分析。在此基础上,采用机械法直接用胶体磨将浒苔原料进行纳米纤丝化,冷冻干燥后制备出全组分的浒苔泡沫材料。 展开更多
关键词 纳米纤丝化 纤维素 海藻 气凝胶 泡沫
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Conductive polypyrrole incorporated nanocellulose/MoS_(2)film for preparing flexible supercapacitor electrodes 被引量:2
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作者 Qi YUAN Ming-Cuo MA 《Frontiers of Materials Science》 SCIE CSCD 2021年第2期227-240,共14页
Conductive films have emerged as appealing electrode materials in flexible supercapacitors owing to their conductivity and mechanical flexibility.However,the unsatisfactory electrode structure induced poor output perf... Conductive films have emerged as appealing electrode materials in flexible supercapacitors owing to their conductivity and mechanical flexibility.However,the unsatisfactory electrode structure induced poor output performance and undesirable cycling stability limited their application.Herein,a well-designed film was manufactured by the vacuum filtration and in-situ polymerization method from cellulose nanofibrils(CNFs),molybdenum disulfide(MoS_(2)),and polypyrrole.The electrode presented an outstanding mechanical strength(21.3 MPa)and electrical conductivity(9.70 S cm^(-1)).Meanwhile,the introduce of hydrophilic CNFs induced a desirable increase in diffusion path of electrons and ions,along with the synergistic effect among the three components,further endowed the electrode with excellent specific capacitance(0.734 F·cm^(-2))and good cycling stability(84.50%after 2000 charge/discharge cycles).More importantly,the flexible all-solid-state symmetric supercapacitor delivered a high specific capacitance(1.39 F·cm^(-2)at 1 mA·cm^(-2))and a volumetric energy density(6.36 mW·h·cm^(-3)at the power density of 16.35 mW cm^(-3)).This work provided a method for preparing composite films with desired mechanical and electrochemical performance,which can broaden the high-value applications of nanocellulose. 展开更多
关键词 cellulose nanofibril molybdenum disulfide POLYPYRROLE flexible supercapacitor
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超分子聚合物刷PVP-Chol表面图案化及其力诱导的可逆结构转变(英文) 被引量:2
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作者 刘姗姗 季姗 +2 位作者 陈启斌 彭昌军 刘洪来 《物理化学学报》 SCIE CAS CSCD 北大核心 2016年第9期2318-2326,共9页
傅里叶变换红外(FT-IR)光谱、表面压力-分子面积(π-A)等温线和原子力显微镜(AFM)结果表明,聚乙烯吡咯烷酮(PVP)与胆固醇分子(Chol)在溶液中和气/液界面上可通过氢键作用形成刷状的超分子聚合物PVP-Chol。当表面压力低于2.5 m N?m^(-1)... 傅里叶变换红外(FT-IR)光谱、表面压力-分子面积(π-A)等温线和原子力显微镜(AFM)结果表明,聚乙烯吡咯烷酮(PVP)与胆固醇分子(Chol)在溶液中和气/液界面上可通过氢键作用形成刷状的超分子聚合物PVP-Chol。当表面压力低于2.5 m N?m^(-1)时,界面膜主要由富含胆固醇的微区与PVP-Chol纳米纤维构成的微区共存。在相对较低的表面压力下(<2.5 m N?m^(-1)),PVP-Chol微区形貌随界面膜压缩发生有序的变化:从最初的无规结构逐渐变为月牙形、心形和圆形结构;表面压超过2.5 m N?m^(-1)后,圆形的PVP-Chol微区最终消失并转变为少量的纤维聚集体结构。值得注意的是,在1.0 m N?m^(-1)之前,PVP-Chol纳米纤维高度随AFM成像过程中压电陶瓷外加电压的变化在1.8到4.3 nm之间出现了可逆转变,表明扫描探针针尖与样品之间的作用力可诱导超分子聚合物刷PVP-Chol发生从圆柱状到椭柱状的可逆结构转变。 展开更多
关键词 氢键 气/液界面 微区 纳米纤维 结构演变 针尖-样品作用力
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大豆蛋白纳米纤维冷凝胶对核黄素的控释研究 被引量:1
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作者 关琛 李萌 +3 位作者 李宁 周航庆 张建红 李琳 《黑龙江八一农垦大学学报》 2022年第1期72-78,共7页
为了扩大大豆分离蛋白(SPI)纤维冷凝胶的潜在使用范围,通过体外缓释模型,探究SPI纤维冷凝胶对核黄素的控释效果。结果表明,SPI在pH 2.0下加热20 h后形成纳米纤维,导致Th T荧光、ζ-电位上升,表观粘度、稠度系数提高。将pH调至8.0后加入C... 为了扩大大豆分离蛋白(SPI)纤维冷凝胶的潜在使用范围,通过体外缓释模型,探究SPI纤维冷凝胶对核黄素的控释效果。结果表明,SPI在pH 2.0下加热20 h后形成纳米纤维,导致Th T荧光、ζ-电位上升,表观粘度、稠度系数提高。将pH调至8.0后加入CaCl_(2)制得的冷凝胶对核黄素具有荷载及控制释放效果。与传统的SPI凝胶相比,这种纤维冷凝胶可以在较低的蛋白浓度下形成凝胶网络,可以用作核黄素的包封体,在食品科学、药物输送等领域具有广阔的应用前景。 展开更多
关键词 大豆蛋白 纳米纤维 冷凝胶 缓释
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Optical and Mechanical Properties of CMCNF-dispersed MMT/CMC-Na Nanocomposite Films: Influence of the Degree of Substitution of CMCNFs 被引量:1
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作者 Guanhui Li Gaoyuan Hou +3 位作者 Hong Xie Dejian Zhang Jinyi Cui Zhiqiang Fang 《Paper And Biomaterials》 2020年第4期18-26,共9页
Carboxymethylated cellulose nanofibril(CMCNF)is an effective green dispersant to prepare well-dispersed monolayer montmorillonites(MMTs)in water,thereby facilitating the preparation of a high-performance MMT/polymer n... Carboxymethylated cellulose nanofibril(CMCNF)is an effective green dispersant to prepare well-dispersed monolayer montmorillonites(MMTs)in water,thereby facilitating the preparation of a high-performance MMT/polymer nanocomposite film.However,not enough attention has been paid to correlating the degree of substitution(DS)of CMCNFs with the mechanical and optical properties of the final nanocomposite films.In this study,a series of homogeneous monolayer MMT nanoplatelet dispersions was prepared initially using CMCNFs with different DS as a dispersant,and the as-prepared CMCNF-dispersed MMT dispersions were then mixed with sodium carboxymethyl cellulose(CMC-Na)to fabricate nacre-like nanocomposite films with different contents of MMTs through self-assembly.The layered nanostructure and optical and mechanical properties of the asprepared CMCNF-dispersed MMT/CMC-Na nanocomposite films were investigated,which demonstrated that CMCNFs with lower DS have a positive effect on their optical and mechanical properties.This study sheds light on the preparation of MMT-based nanocomposite films with superior optical and mechanical properties. 展开更多
关键词 carboxymethylated cellulose nanofibril degree of substitution green dispersant MONTMORILLONITE nanocomposite film
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Preparation of Cellulose Nanofibrils by Multi-Site Regioselective Oxidation 被引量:1
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作者 Liying Song Xixiang Pei +2 位作者 Rui Li Haitao Chen Xiaozheng Sun 《Journal of Renewable Materials》 SCIE EI 2020年第10期1269-1282,共14页
Cellulose nanofibrils(CNFs)are promising sustainable materials that can be applied to nanocomposites,as well as medical and life-sciences devices.However,methods for the preparation of these important materials are en... Cellulose nanofibrils(CNFs)are promising sustainable materials that can be applied to nanocomposites,as well as medical and life-sciences devices.However,methods for the preparation of these important materials are energy intensive because heating and mechanical disintegration are required to produce cellulose fibers below 100 nm in size.In this study,CNFs were prepared through the multi-site regioselective oxidation of cellulose with 2,2,6,6-tetramethylpiperidine-1-oxyl(TEMPO)and periodate at room temperature(20–25°C),without any mechanical-disintegration treatment.Transmission electron microscopy(TEM)revealed that the CNFs had the average widths of 14.1,55.4,and 81.9 nm for three different treatments.Fourier-transform infrared spectroscopy revealed that carboxyl groups were created on the surfaces of the microfibrils,while X-ray diffraction studies showed that the cellulose I structure was maintained after oxidation,and that the cellulose nanofibril crystallinity index exceeded 70%.These results demonstrate that CNFs can be prepared by multi-site regioselective oxidation at room temperature in the absence of mechanical disintegration.In addition,a model was developed to calculate the total content of carboxylate and aldehyde groups of CNFs prepared by the TEMPO mediate oxidation,the periodate oxidation,and the multi-site regioselective oxidation methods based on the particle width determined by TEM.The calculated values of the model were in good agreement with the total content(experimental value)of carboxylate and aldehyde groups of CNFs prepared by the TEMPO-mediated oxidation and the multi-site regioselective oxidation methods.However,the model was not valid for CNFs prepared by the periodate oxidation method. 展开更多
关键词 Cellulose nanofibril multi-site regioselective oxidation total content of carboxylate and aldehyde groups particle width
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Morphology and Microstructure of Spider Dragline Silk from Araneus Ventricosus
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作者 潘志娟 三浦幹彦 +2 位作者 森川英明 岩佐昌征 刘敏 《Journal of Donghua University(English Edition)》 EI CAS 2005年第1期73-77,共5页
The spider dragline silk has excellent mechanical properties. The stress- strain curves of dragline silk fibers have intraspecific and intraindividual variability because of the spider’s active control during spinnin... The spider dragline silk has excellent mechanical properties. The stress- strain curves of dragline silk fibers have intraspecific and intraindividual variability because of the spider’s active control during spinning process. To investigate the relationship between the morphology of dragline silk fibers and spinning conditions, four samples were made at the reeling rates of 1 mm/s, 20 mm/s, 43.5 mm/s and 110 mm/s from the major ampullate glands of Araneus Ventricosus and the other two of dragline silks were prepared from a crawling or dropping spider. The surface microstructure and nanofibril characteristic were analyzed with atomic force microscopy (AFM). AFM images of 2 000 nm *2 000 nm and 500 nm*500 nm of these samples showed that the spinning condition influenced the surface roughness and fibril size, while AFM images of 200 nm*200 nm clearly displayed that dragline silk of Araneus Ventricosus included sheet macro-conformation structure. These results can facilitate the further investigation of the spinning mechanism of a spider in order to understand mechanical properties and macromolecular structures of dragline silk. 展开更多
关键词 Spider silk Atomic force microscopy MICROSTRUCTURE nanofibril.
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