Cellulose nanofiber-derived carbon aerogel for advanced room-temperature sodium–sulfur batteries

Room-temperature sodium–sulfur(RT/Na–S)batteries are regarded as promising large-scale stationary energy storage systems owing to their high energy density and low cost as well as the earth-abundant reserves of sodium and sulfur.However,the diffusion of polysulfides and sluggish kinetics of conversion reactions are still major challenges for their application.Herein,we developed a powerful and functional separator to inhibit the shuttle effect by coating a lightweight three-dimensional cellulose nanofiber-derived carbon aerogel on a glass fiber separator(denoted NSCA@GF).The hierarchical porous structures,favorable electronic conductivity,and three-dimensional interconnected network of N,S-codoped carbon aerogel endow a multifunctional separator with strong polysulfide anchoring capability and fast reaction kinetics of polysulfide conversion,which can act as the barrier layer and an expanded current collector to increase sulfur utilization.Moreover,the hetero-doped N/S sites are believed to strengthen polysulfide anchoring capability via chemisorption and accelerate the redox kinetics of polysulfide conversion,which is confirmed from experimental and theoretical results.As a result,the assembled Na–S coin cells with the NSCA@GF separator showed a high reversible capacity(788.8 mAh g^(−1) at 0.1 C after 100 cycles)and superior cycling stability(only 0.059%capacity decay per cycle over 1000 cycles at 1 C),thereby demonstrating the significant potential for application in high-performance RT/Na–S batteries.

Oxidizing Cellulose to 2,3-Dialdehyde Cellulose by Sodium Periodate

Study on oxidizing cellulose to 2.3-dialdehyde cellulose by sodium periodate （NalO4） was carried out. The effects of reaction conditions such as pH of solution, temperature, oxidant concentration, oxidation time. the particle size of 2,3-dialdehyde cellulose and alkali treatment temperature on the dialdehyde concentration ot cellulose were investigated in detail, The results show that the aldehyde group content was created while reaction temperature and alkali treatment temperature increased. The most principal factors affecting the aldehyde group content of 2,3-dialdehyde cellulose were found out and the best oxidation conditions were as follows： the pH was 2. the reaction temperature was 45℃. the mass ratio of cellulose to NalO4 was 1/2, the reaction time was 4 h, the alkali treatment temperature was 70℃ and smaller particle size was 0.80 mm.

Adsorption Behavior and Inhibition Corrosion Effect of Sodium Carboxymethyl Cellulose on Mild Steel in Acidic Medium

The effect of sodium carboxymethyl cellulose (Na-CMC) on the corrosion behavior of mild steel in 1.0 mol·L-1 HCl solution has been investigated by using weight loss (WL) measurement, potentiodynamic polarization, linear polarization resistance (LPR), and electrochemical impedance spectroscopy (EIS) methods. These results showed that the inhibition efficiency of Na-CMC increased with increasing the inhibitor concentration. Potentiodynamic polarization studies revealed that the Na-CMC was a mixed type inhibitor in 1.0 mol·L-1 HCl. The adsorption of the inhibitor on mild steel surface has been found to obey the Langmuir isotherm. The effect of temperature on the corrosion behavior of mild steel in 1.0 mol·L-1 HCl with addition of 0.04% of Na-CMC has been studied in the temperature range of 298-328 K. The associated apparent activation energy (E*a ) of corrosion reaction has been determined. Scanning electron microscopy (SEM) has been applied to investigate the surface morphology of mild steel in the absence and presence of the inhibitor molecules.

Preparation and Properties of Nanocellulose/Sodium Alginate Composite Hydrogel

Cellulose nanofiber(CNF)was isolated from Okara using deep eutectic solvent(DES)with high-speed stirring.The composite hydrogels obtained by using different proportions of CNF and sodium alginate(SA)had different properties.The CNF/SA composite hydrogels were analyzed using Fourier transform infrared spectroscopy and scanning electron microscopy and tested for compression properties,rheological properties,water content,and swelling degree.Physical crosslinking between SA and Ca^(2+),and different degrees of hydrogen bond formation between SA and CNF were observed.The CNF/SA composite hydrogel have great potential as reinforcements in eco-friendly composite hydrogels for diverse applications.

Effect of carboxymethyl cellulose on dissolution kinetics of carboxymethyl cellulose-sodium carbonate two-component tablet

Sodium carbonate and carboxymethyl cellulose powders are compressed into two-component tablets with three mass ratios,97%:3%,95%:5% and 93%:7%.The dissolution tests for two-component tablets and reference pure sodium carbonate tablets are carried out at various temperatures.The dissolution process of each tablet is measured by electrical conductivity tracking method and the concentration of dissolved sodium carbonate is quanti fied with calibrated conductivity-concentration converting equation of sodium carbonate.The quanti fied dissolution data is fitted with both surface reaction model and diffusion layer model and the results clearly show that surface reaction model is suggested as the appropriate dissolution model for all measured tablets.Therefore,it is determined that carboxymethyl cellulose is a stable element to remain the dissolution mechanism of tablet unchanged.The dissolution rate constant quanti fied with surface reaction model presents that carboxymethyl cellulose-sodium carbonate two-component tablets obtain signi ficant higher dissolution rate constant than pure sodium carbonate tablet and higher proportion of carboxymethyl cellulose leads to apparent higher dissolution rate constant.The results prove for the usage of carboxymethyl cellulose in most practical applications at a relative low-level,the effect of carboxymethyl cellulose is effective and positive for two-component tablet to enhance the dissolution process and improve dissolution rate constant and this effect is speculated coming from its dynamic physical transforming process in water including dilation and conglutination.

Preparation of Waterborne Nanoscale Carbon Black Dispersion with Sodium Carboxymethyl Cellulose

Waterborne nanoscale carbon black dispersion （NCBD） was widely used in inkjet printing, spun.dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose （CMC） as dispersant. Effects of CMC viscosity, ultrasonic time and oxidation with hydrogen peroxide on carbon black （CB） particle size were discussed. The results showed that CB particle size decreased by mechanical agitation while it Increased by ultrasonic with the increase of CMC viscosity. Uitrasonk is a more effective method to disperse CB particles than that of mechanical agitation. CB particle size lbviously decreased with itcreasing ultrasonic time and arrived at about 160 nm for 60min.In addition,oxidation with 2 mol/L of H2O2 and 0.2wt% of CMC300 reduced CB particle size to 160nm at 90℃ for 2.5h.

Homogeneous Synthesis and Characterization of Quaternized Cellulose Derivatives in NaOH-urea Aqueous Solutions

Quaternized cellulose( QC) derivatives were synthesized by reacting cellulose with 3-chloro-2-hydroxypropyl trimethyl ammonium chloride( CHPTAC) in an aqueous solution of Na OH-urea. The chemical structures and physical properties of the obtained QC derivatives were characterized using nitrogen content analysis,Fourier transform infrared spectroscopy( FT-IR),~1H-nuclear magnetic resonance(1H-NMR),X-ray diffraction( XRD),and thermal gravity analysis( TGA). The FT-IR and ~1H-NMR results confirmed the successful introduction of cationic quaternary ammonium groups into the main chain of cellulose. A series of QC derivatives with the degree of substitution( DS) values ranging from 0. 33 to 0. 80 were derived by adjusting the molar ratio of CHPTAC to anhydroglucose unit( AGU) of cellulose,concentration of cellulose in the Na OH-urea solution,as well as reaction temperature and time. According to the DS values of the QC derivatives,the optimized synthetic conditions were as follows: 25℃ reaction temperature,3% cellulose in Na OH-urea solution,the molar ratio of etherification agent to glycosidic cellulose of 15∶ 1,and 12 h reaction time. The TGA and XRD results revealed that the crystalline structure was destroyed during etherification,and the thermal stability of the QC derivatives was lower than that of cellulose.

羟丙基淀粉植物胶囊的研究

以羟丙基淀粉(HPS)为主料,羧甲基纤维素钠(CMC-Na)和海藻酸钠(SA)为增强剂,并辅以凝胶剂和塑化剂,制备了复合植物胶囊HPS/CMC-Na/SA,采用单因素实验和正交实验优化了制备工艺,并通过SEM、FTIR、XRD对其进行表征。结果表明,当HPS加量为85 mg·mL^(-1)、CMC-Na加量为8.5 mg·mL^(-1)、SA加量为4.5 mg·mL^(-1)时,复合植物胶囊的抗拉强度为30.08 MPa,断裂伸长率为14.49%,杨氏模量为1289.77 MPa,800 nm透光率为78.068%,400 nm透光率为63.072%。

DCG复合气凝胶的制备及对刚果红的吸附性能

微晶纤维素(MCC)通过选择性氧化得到二醛纤维素(DAC),再与壳聚糖(CS)、葡萄糖(G)交联制备DAC/CS/G(DCG)复合气凝胶。采用SEM、FTIR对DCG气凝胶进行表征,并考察其对刚果红(CR)的吸附作用。结果表明,MCC被高碘酸钠氧化后引入活性基团醛基,可与CS、G发生化学交联和氢键键合,提高了对刚果红的吸附效果。与原MCC相比,DCG呈现较均匀密集的多孔结构;DCG的吸附过程均遵循准二级动力学模型和Langmuir等温模型;不同氧化度的DCG相比,DCG-0.06的吸附速率和容量更佳,当染料初始质量浓度为600 mg/L时,其单分子层理论最大吸附量可达到649.35 mg/g。

鱼尾型搅拌桨设计及在羧甲基纤维素钠溶液中的应用

搅拌桨是生物反应器的核心部件,直接影响反应釜内流体的搅拌混合和气液分散性能.基于双色刺尻鱼(Centropyge Bicolor)尾鳍轮廓特征和仿生学原理,设计了一种鱼尾型搅拌桨—FT桨(Fishtail Turbine),应用于羧甲基纤维素钠(CMC)溶液的搅拌混合操作.结合计算流体动力学(CFD)和粒子图像测速(PIV)技术,研究了FT桨在纯水、 CMC溶液中的搅拌混合和气液分散性能,并与传统RT桨(Rushton Turbine)进行了对比.结果表明:(1)对于单相流,与RT桨相比,FT桨能增大流场速度、湍动能作用区域;搅拌纯水、 0.25%CMC溶液、 0.5%CMC溶液时,湍动能最大值分别增加39.47%、 23.33%、 18.31%,平均增加31.03%.(2)对于气液两相流,与RT桨相比,FT桨能增大高气含率区域,促进气液分散;搅拌气液两相纯水、 0.25%CMC溶液、 0.5%CMC溶液时,总体气含率分别相对增加8.62%、 9.19%、 2.58%,平均相对增加5.94%,搅拌功耗分别降低4.58%、 4.54%、 4.98%,平均降低4.70%.与RT桨相比,FT桨搅拌CMC溶液具有更优的搅拌混合和气液分散性能,应用前景广阔.

黄麻可降解包装材料制备及性能研究

研究一种基于黄麻、粘胶、水性聚氨酯和羧甲基纤维素钠(CMC)的可降解包装材料的制备。采用非织造生产工艺,以可降解的黄麻和粘胶为原料,纤维梳理成网后,经针刺机针刺,再将水性聚氨酯和CMC溶于水中,形成悬浮液均匀喷洒至纤维网,烘干后热压成型得到生物可降解包装材料。对比聚乳酸、水性聚氨酯、CMC的成本及力学性能,探究材料混比对黄麻/粘胶/水性聚氨酯/CMC包装材料断裂强力和断裂伸长率的影响,并通过干燥和湿润试样的强力对比,探究了黄麻/粘胶/水性聚氨酯/CMC包装材料的耐水性能。结果表明,当黄麻/粘胶/水性聚氨酯/CMC混比为40/40/15/5,面密度为100 g/m^(2)时,所得样品纵、横向断裂强力分别为155.5 N、52.6 N,将样品浸渍于水中1 h后取出,其纵、横向的湿态强力保留率分别为49.9%、69.2%,可满足包装袋力学性能的要求。

复合黏结剂对铁精矿球团质量的影响

为充分发掘有机黏结剂对铁精矿球团质量提升的优点,同时弥补有机复合黏结剂削弱成品球抗压强度的不足,本文将蛭石、羧甲基纤维素钠(有机黏结剂)、膨润土进行复配,探究复合黏结剂对铁精矿球团质量的影响,并借助SEM和热重分析探索蛭石改善成品球强度的机理。试验结果表明:在不复配有机黏结剂,仅仅添加1%的膨润土时,球团的落下强度只有1.5次/(0.5 m),抗压强度为8.2 N/P,爆裂温度为550℃,在预热温度为950℃、焙烧温度为1200℃时成品球的强度为3121 N/P;固定膨润土用量,随着有机黏结剂复配比例增加到0.12%,生球落下强度可提升到8.0次/(0.5 m),抗压强度提升到11.3 N/P,但生球的爆裂温度下降到395℃,成品球强度下降到2465 N/P;加入0.03%蛭石+0.12%有机黏结剂+1%膨润土的复合黏结剂后,球团的质量指标最好,球团落下强度可达到6.5次/(0.5 m),抗压强度为13.4 N/P,爆裂温度为362℃,成品球强度在相同条件下可以提升至2764 N/P。SEM和热重分析结果表明:蛭石膨胀能不断填充球团中的孔隙,在焙烧过程中生成液相,有利于固相扩散晶体长大,降低球团孔隙率,从而提升成品球的抗压强度。

纤维素/海藻酸钠/明胶复合水凝胶的制备与性能

纤维素作为一种来源丰富的天然高分子材料,具有优异的生物相容性和可降解性,但其难溶特性限制了其应用。文中采用离子液体1-烯丙基-3-甲基咪唑氯化物(AmimCl)溶解纤维素(Cel),海藻酸钠(SA)与明胶(Gel)混合水溶液作为凝固浴进行纤维素再生,进一步通过浸泡氯化钙(CaCl_(2))溶液交联海藻酸钠,制备了一种透明、高强度的复合水凝胶。分别探究了纤维素浓度(3%,4%,5%,6%,7%和8%)及不同的海藻酸钠/明胶质量比(0:10,2:8,4:6,6:4,8:2和10:0)对水凝胶性能的影响。利用傅里叶变换红外光谱、扫描电子显微镜、X射线衍射仪、紫外可见分光光度计和万能材料试验机对水凝胶进行了表征。结果表明,水凝胶中各组分之间的氢键作用及海藻酸钠与Ca^(2+)之间的离子相互作用赋予水凝胶优异的力学性能,相比于纯水作为凝固浴制备的再生纤维素水凝胶,强度提高了26.36%。随着纤维素浓度的增加,水凝胶的结晶度和网络结构的致密性增加,水凝胶的力学性能显著提升。此外,海藻酸钠/明胶的比例也对水凝胶的力学性能有显著影响,当海藻酸钠与明胶质量比为6:4时,水凝胶力学性能最好,最高达到2.349 MPa。生物降解性分析表明,水凝胶具有良好的生物降解性,在食品包装和生物医药领域具有潜在应用价值。

羧甲基纤维素钠对红海榄幼苗生长和土壤养分的影响

为明确羧甲基纤维素钠(Sodium Carboxymethyl Cellulose,CMC)对沿海困难立地砂砾质土壤的改良作用,以红海榄(Rhizophora stylosa)胚轴为材料,通过室内潮汐模拟试验,研究不同CMC施用量(质量比为1.6%、2.4%、3.2%、4.0%和4.8%)对红橄榄幼苗生长和土壤养分的影响。结果表明,随CMC施用量增加,红海榄幼苗生长量和生物量整体呈先增后减的趋势,均在4.0%CMC处理下最大。与CK相比,不同CMC处理下红海榄幼苗的株高、地径和叶片数分别增加9.78%~38.54%、13.83%~54.31%和20.00%~36.67%;根、茎和叶生物量分别增加10.58%~64.72%、7.97%~36.76%和37.62%~117.99%;土壤有机质、全钾和速效钾含量分别显著增加625.22%~671.96%、147.62%~161.52%和55.56%~77.78%。CMC可促进红海榄幼苗生长,提高土壤养分,可作为沿海困难立地砂砾质土壤的改良剂,推荐CMC施用量为4.0%。

负载七叶苷的水凝胶制备及初步评价

本试验旨在制备一种可用于局部递送七叶苷的水凝胶。选择羧甲基纤维素钠(CMC-Na)与羧甲基壳聚糖(CMCS)为原料,向其中添加七叶苷(ESC),制备负载七叶苷的CMC-Na/CMCS水凝胶(CCE),并对其性质和功能进行研究。本试验成功制备了CCE水凝胶,并以不同比例的CMC-Na/CMCS设计正交试验,依据载药量和包封率筛选,最终确定水凝胶的配方为2%CMC-Na、2%CMCS、200μL京尼平,转速为800 r·min^(-1),水凝胶外观为蓝色溶液,无析出、无杂质、透明度均匀;扫描电镜可见其具有三维结构和许多光滑小孔;粒径为0.8415 nm,Zeta电位为-32.1 mV;傅里叶红外光谱和X射线衍射均表明七叶苷成功载入到CMC-Na/CMCS水凝胶中且未影响其原有的官能团;溶胀率为234%;体外释放时间比原料药明显延长;同浓度载药凝胶比原料药抗菌效果有所延长,效果较好。本试验成功将七叶苷载入到了CMC-Na/CMCS水凝胶中,并通过系列试验证明其相较七叶苷原料药具有一定的缓释作用,可以延长药物作用时间,减少给药次数,为临床使用七叶苷治疗疾病提供了一种新的给药方式。

海藻酸钠-羟乙基纤维素可降解复合膜制备和性能

为制备性能优异的SA(海藻酸钠)可降解复合膜,以HEC(羟乙基纤维素)为增强组分,采用浇铸法制备一系列不同SA与HEC质量比的可降解复合膜,然后利用Ca^(2+)进行交联处理,并采用土埋法进行降解实验。通过FTIR、SEM、TGA、UV/VIS/NIR等对其组成结构、力学性能等进行测试与表征。结果表明:HEC的加入极大改善了SA膜质脆易皱缩的特点,复合膜的力学性能优异,韧性和透明度良好,耐热和疏水性能也有显著提升。明确了最佳实验条件,当SA与HEC质量比为4∶1时,膜的拉伸断裂强度为64.6 MPa,断裂伸长率为3.62%,水接触角为63.3°,氧气透过量为(2.54±0.056) cm^(3)/(cm^(2)·d·MPa),可见光透过率为33.3%—52.9%,并具有良好的可降解性。因此,以HEC为增强组分制备的SA复合膜具有良好的力学性能和降解性能,可应用于食品包装领域。

高电导率抗冻离子凝胶的制备及性能研究

近年来,可穿戴设备在人体运动、身体体征以及体液检测等方面得到广泛应用。离子凝胶依靠其优异的离子导电性、热稳定性和电化学性能,广泛应用于柔性传感器,包括传感单元和柔性电极。大多数可穿戴传感器对低温条件的适应度不高,这阻碍了其在不同环境下的使用。鉴于此,本工作提出了一种高电导率抗冻离子凝胶,将丙烯酸(AA)、羧甲基纤维素钠(CMC)、丙烯酰胺(AAm)三种物质以AA与CMC,AA与AAm,AA、CMC和AAm三种组合相互形成共聚网络,并加入LiCl导电物质来制备一种在低温下依旧能保持良好电化学性能的离子凝胶。在三种类型的离子凝胶中,AA-CMC离子凝胶具有最高的电导率和对金属类器件表面最好的粘附性,对铁片的最大粘附力可达51.39 kPa,同时还具有优良的保湿抗冻功能(在25℃下7 d内失水率仅为4%以及-76℃的凝固点)和207.10%的断裂生长率。AA-CMC离子凝胶具有较好的导电性能(电导率最大为0.617 S/m)及柔软特性,可以组装成可穿戴柔性压力传感器;具有稳定的电化学性能且在长期在低温下也能保持自身的导电性能(-18℃冷冻3周电导率保持约原有的86.3%)。本工作所制备AA-CMC的离子凝胶将有望扩展其在柔性电子设备中的应用范围与使用前景。

CMC-Na复合纳米SiO_(2)煤炭阻燃抑尘剂的制备及应用

为解决煤炭储运中的扬尘污染及自燃问题,以改性纳米二氧化硅(SiO_(2))、羧甲基纤维素钠(CMC-Na)为主要原料,十二烷基苯磺酸钠(SDBS)为表面活性剂,采用水溶液聚合法合成了一种高分子煤炭阻燃抑尘剂。采用FTIR、XRD、SEM、TG等对产品的结构进行了分析表征,并对其阻燃性能、成膜柔韧性、保水性、抗风蚀性、接触角、渗透性等应用性能进行了测试。结果表明,合成的阻燃抑尘剂成膜柔韧;添加此阻燃抑尘剂的煤样在高温燃烧时CO释放量比添加水的煤样降低了63.6%,阻燃性能显著提高,保水性提高了53.4%,抗风蚀性提高了43.1%,满足了煤炭储运中防尘的需求;阻燃抑尘剂在煤表面的接触角比水降低了36.46°,渗透速率是水的5倍,具有良好的渗透固结性能。

紫外光引发制备PAA/CMC高吸水树脂及性能研究

以羧甲基纤维素钠(CMC)为骨架,通过紫外光引发聚合将单体丙烯酸(AA)接枝到CMC骨架上,合成PAA/CMC高吸水树脂。采用单因素实验法优化并确定了具有最高吸水能力的树脂的最佳制备条件。结果表明,合成树脂的最优条件为:CMC用量为0.05 g,AA质量浓度为0.48 g/mL,中和度为40%,引发剂和交联剂的用量分别为AA质量的0.3%和0.05%,反应时间55 min。所制备的高吸水树脂在蒸馏水中的最大吸水倍率为1281.21 g/g,在生理盐水中的最大吸水倍率为69.42 g/g。采用红外、热重以及扫描电镜对树脂的结构进行表征。结果表明,该制备方法成功合成了PAA/CMC高吸水树脂,其具有较好的热稳定性,树脂表面有明显的褶皱结构,具有吸水速率快、保水性好等特点。

三元共聚生物质基矿山爆破抑尘剂的制备及性能研究

以接枝共聚制备羧甲基纤维素钠(CMC-Na)-羧甲基淀粉钠(CMS-Na)-丙烯酰胺(AM)三元复合高分子抑尘剂,以黏度为测试指标,通过正交试验探索抑尘剂最优配比。用扫描电镜(SEM)、傅里叶红外光谱(FT-IR)、热重(TG)对接枝共聚产物进行表征,对抑尘剂黏度、抗风蚀性、保水性、渗透性等理化特性进行测试。结果表明:CMC-Na∶CMS-Na∶PVA∶AM=8∶8∶3∶16时,制备抑尘剂最大黏为52689 mPa·s;借助黏度及保水性指标确定抑尘剂喷洒最佳体积分数为8%;木质素磺酸钠和三乙醇胺最优添加量分别为抑尘剂质量分数的0.4%和4%。红外光谱显示丙烯酰胺接枝到羧甲基淀粉和羧甲基纤维素钠上,扫描电镜显示抑尘剂对粉尘的凝并和黏结性能显著,抗风蚀性实验表明抑尘剂固尘率为85.47%。