Preparation of alginate-gelatin capsules and its properties

Capsules based on alginate and gelatin prepared by extrusion method could increase the cell numbers of Lactobacillus casei ATCC 393 to be 10⁸ CFU·g⁻¹ in the wet state of the capsules. The capsules were spherical, smooth-surfaced and non-aggregated with a diameter of (4.0 ± 0.3) mm. The behavior of the samples were quite similar at low relative humidity (33%, 52%) and the ratio of weight change reached 93%. Four kinds of capsules in simulated gastric fluid (SGF) exhibited shrinkage while the beads eroded accompanied with slight swelling in simulated intestinal fluid (SIF). The pH values affected the stability of the capsules and with the increase in pH, the capsules changed from shrank then swelled and finally, broke into pieces. The capsules behaved differently under different ion intensities and the introduction of gelatin weakened the stability of capsules compared with the alginate ones. Cells of L. casei ATCC 393 could be continuously released from the capsules in the simulated gastrointestinal tract (GIT) and the release amounts and speeds in SIF were much higher and faster than those in SGF.     

季铵化聚醚砜酮的制备及其膜性能

以浓硫酸为溶剂,氯甲基丁醚、三甲胺为改性试剂,通过氯甲基化／季铵化两步反应制备了季铵化聚醚砜酮(QAPPESK)。详细讨论了两步反应的影响因素。对氯甲基化聚醚砜酮(CMPPESK)进行了^1H—NMR核磁表征,测试了CMPPESK、QAPPESK的溶解性和5％热失重温度。将此材料制备成纳滤膜用于染料脱盐,并考察了其耐酸性和抗污染性,发现QAPPESK是较为优异的膜材料。     

Preparation of stimuli-responsive nano-sized capsules based on cyclodextrin polymers with redox or light switching properties

We report the preparation and encapsulation properties of stimuli-responsive nanocapsules, self-assembled by the noncovalent interactions of cyclodextrinappended polymers (host) and complementary ferrocene or azobenzene carriers (guest). The encapsulation process was significantly accelerated by applying (electro) chemical or light stimulus, enabling the easier and faster diffusion of guest molecules through the polymer layers. The nanocapsules were characterized by dynamic light scattering, confocal microscopy, ESEM, AFM, UV–visible and fluorescence spectroscopy, and electrochemical techniques. The encapsulation and release properties of the nanocapsules were reversible and could be repeated several times, indicating that the prepared nanoassemblies are very stable.

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Porous graphene gels: Preparation and its electrochemical properties

Ultra-light porous 3D network graphene oxide (GO) gels were prepared using a simple process of aqueous gel precursor freezing, solvent exchange, and ethanol drying rather than supercritical drying technology. The GO sheets were consolidated by cross-linked sodium alginate (SA) and the obtained GO–SA gel was reduced by glucose to prepare graphene nanosheet–SA (GN–SA) gel. The gels were characterized by FTIR, XRD, SEM, and nitrogen adsorption–desorption measurements. SA was proven to attach to GO or GN surfaces to form gels composed of macropores and mesopores. GO–SA gel exhibited a bulk density of 16.79 mg cm⁻³, and adsorbed water 17.4 times, ethanol 20.5 times, and soybean oil 22.4 times the weight of GO–SA gel, while GN–SA gel exhibited a lower bulk density of 12.93 mg cm⁻³, and adsorbed water 12.2 times, ethanol 16.9 times and soybean oil 32.3 times the weight of GN–SA gel. The electrochemical performance of the GN–SA gel was analyzed using cyclic voltammetry, electrochemical impedance spectrometry, and chronopotentiometry. The results revealed that GN–SA gel displayed superior capacitive performance with large capacitance (114.12 F g⁻¹) and excellent cyclic performance.     

新型二元水凝胶的合成及智能性研究

为了研究溶胀体积可随外界环境因素智能变化的吸水凝胶,用微波等离子体预辐射引发聚合P(AMPS/NIPA)新型二元水凝胶.探讨了等离子体预辐射时间、等离子体预辐射功率、交联剂浓度、单体配比和总单体浓度等因素对二元水凝胶吸水倍数的影响,对合成工艺进行了优化.研究了水凝胶的温度敏感性、pH敏感性,并用红外光谱对P(AMPS/NIPA)水凝胶官能团进行了表征.研究表明,微波等离子体预辐射引发聚合制备的P(AMPS/NIPA)二元智能凝胶具有高的吸水倍数、很好的温度敏感性和pH敏感性,是综合性能优秀的智能水凝胶.     

核-壳纳米Ag@ZrO_2复合材料的制备及其抑菌性能

首先,采用溶胶-凝胶法以锆酸四丁酯为原料制备了直径约为230nm单分散性ZrO_2亚微球;然后,以ZrO_2为前体,加入少量AgNO3,用物理方法将Sn2+离子吸附在ZrO_2表面,Ag+被还原成Ag0负载在ZrO_2表面合成Ag@ZrO_2晶种,加入甲醛合成核-壳纳米Ag@ZrO_2复合材料;最后用TEM、XRD和UV-Vis对制备的ZrO_2和Ag@ZrO_2进行表征,并研究其对金黄色葡萄球菌(S.aureus)和大肠杆菌(E.coli)的抑菌性能。结果表明:当Ag浓度为0.6mg/mL时,Ag@ZrO_2对S.aureus和E.coli的抑菌率分别为95.5%和99.0%。因此,Ag@ZrO_2作为理想的抗菌材料可以应用于日常生活和医疗实践中。     

石墨烯改性PDC-SiCNO陶瓷的制备及其介电性能

以聚乙烯基硅氮烷(PVSZ)为原料,氧化石墨烯(GO)为碳源,无水乙醇(ETOH)为分散剂,制备石墨烯球增强SiCNO陶瓷(SiCNO-GO)。利用拉曼光谱(Raman)、电子自旋共振(EPR)和扫描电子显微镜(SEM)等表征手段,研究SiCNO-GO陶瓷结构对其介电性能的影响。结果表明:SiCNO-GO陶瓷的微球密度和粒径的大小与GO的含量有关;随着SiCNO-GO陶瓷中GO含量的增加,SiCNO-GO陶瓷的介电常数和介电损耗也随之增大,在GO含量为0.1%(质量分数)时达到最大值,而当GO质量分数为0.3%时,SiCNO-GO陶瓷的介电常数和介电损耗降低。     

多元LDHs/EVA纳米复合材料的制备及性能研究

以氯化镁(MgCl2.6H2O)、氯化铝(AlCl3.6H2O)、氯化锌(ZnCl2)、氯化铁(FeCl3.6H2O)和碳酸钠(Na2CO3)为原料,采用共沉淀法制备了二元MgAl-CO3LDHs、三元MgAlZn-CO3LDHs和四元MgAlZnFe-CO3LDHs无机纳米粉体,用聚乙二醇(PEG)对3种LDHs进行原位改性,采用熔融共混法制备了EVA/LDHs纳米复合材料,并对LDHs和纳米复合材料进行了透视电子显微镜(TEM)、扫描电子显微镜(SEM)、X射线衍射(XRD)、热重分析(TG)、力学性能、燃烧性能等测试。结果表明加入LDHs纳米粉体后,虽然对复合材料的力学性能有一定的影响,但对复合材料的阻燃效果有着明显的改善;而且随着LDHs元数的增加,复合材料的阻燃效果得到明显提高;当四元MgAlZnFe-CO3LDHs的添加量为15%时,复合材料即可自熄。     

天然石墨/陶瓷复合材料的制备及其性能

为了拓展天然石墨的应用领域，通过热压工艺，在天然石墨中掺杂B、Si和Zr陶瓷组元，制备了天然石墨／陶瓷复合材料，利用SEM、XRD等分析手段研究了材料微观结构，并探讨了掺杂组元以及天然石墨颗粒大小对材料性能的影响．结果表明：掺杂Zr可有效地提高石墨材料的热导率，B的加入可有效地提高石墨材料的力学性能，而Si的加入可加速Zr对石墨材料的催化石墨化；随着天然石墨粒径的增加，制得石墨材料的热导率也随之增加，其中，以粒径为13μm的天然石墨制得的材料强度和密度为最优。     

Ag(TCNQ)纳米线的制备和电学特性研究

提出了一种新的制备有机金属配合物纳米线的方法,即饱和蒸气反应法,并解释了它的生长机理。用这种方法制备的Ag(TCNQ)[TCNQ,tetracyanoquinodimethane]纳米线(棒)基本垂直于基板。截面近似呈方形,边长<100nm,长度(高度)可控,生长温度低(≤120℃),因而在实际应用过程中容易与其它工艺兼容。在STM针尖和导电AFM针尖电场作用下这种纳米线(棒)具有电双稳特性,预期在纳米电子学方面有广泛的应用前景。     

纳米氧化高银的制备及抗菌性能

采用液相氧化沉淀法制备纳米氧化高银颗粒.以硝酸银为原料,氢氧化钠为沉淀剂,过硫酸钾为氧化剂,控制pH值为11,反应温度为80℃,在磁力搅拌器上反应30min,静置3h后,离心洗涤数次,70℃真空干燥3h,得到黑色纳米氧化高银颗粒.通过X射线衍射(XRD)、透射电子显微镜(TEM)对纳米氧化高银颗粒的形貌和结构进行表征;采用异养菌测试瓶法,用制备的氧化高银和粒径为30nm的纳米银对金黄色葡萄球菌进行抗菌性能测试.结果表明:制得的球形纳米颗粒粒径为10～30ntn;纳米氧化高银颗粒比纳米银具有更强的杀菌性能.     

二氧化钛薄膜材料的制备及其性能研究

采用溶胶-凝胶法,以钛酸丁酯[Ti(OC4O9)]4为原料,乙醇为溶剂,冰醋酸为抑制剂,制备了二氧化钛薄膜,同时以硝酸镧和硝酸镍为掺杂物制备了单掺、共掺的二氧化钛薄膜,研究了其可见光吸收性能和光催化降解性能。实验表明,掺杂后的二氧化钛薄膜在可见光区仍有明显吸收,掺镧的二氧化钛薄膜对亚甲基蓝降解效果较好,光催化降解率达到76.54%。     

Ag-MMOFs复合材料的制备及其对硝基苯酚的降解作用

采用双溶剂法制备Ag-ZIF-8(Zn-Co)多金属MOFs材料,并将其用于对硝基苯酚、邻硝基苯酚和对硝基苯胺等污染物的催化还原;利用扫描电子显微镜(SEM)、 X射线衍射仪(XRD)、透射电镜(TEM)对制备的材料进行表征。结果表明:Ag-ZIF-8(Zn-Co)在催化降解3种污染物方面表现出优异的催化活性;Ag-ZIF-8(Zn-Co)催化降解对硝基苯酚反应的表观速率常数和转换频率分别为1.080×10~(-4) s~(-1)和2.056 min~(-1),并在多次重复使用过程中保持较高的催化性能;与单金属复合材料Ag-ZIF-8和Ag-ZIF-67相比,Ag-ZIF-8 (Zn-Co)的催化活性显着提高,主要原因是Ag-ZIF-8(Zn-Co)具有高比表面积,Zn和Co双金属的协同作用,以及孔道对银纳米颗粒的限制等。     

Preparation of SiC and SiC/ZnO nanocomposites and its properties

SiC/ZnO nanocomposites were synthesized via a two-stage process. SiC nanoparticles were synthesized by electrical explosion method, and using the SiC nanoparticles as precursor, SiC/ZnO nanocomposites were synthesized by co-precipitation processes. The SiC/ZnO nanocomposites exhibit energy tuning of band-to-band transitions. In addition to the UV emission, the green and orange emissions were also observed. To our interest the green and orange emissions decreased at first and then increased with increasing annealing temperature. The underlying mechanism is elucidated.     

纳米银-聚合物薄膜的制备及力电性能测试

聚合物基底上纳米银颗粒薄膜的制备工艺相对简单,成本较低,且该薄膜具有成为高敏感性压阻应力/应变传感材料的潜力。本文采用银镜制备法在聚酰亚胺(PI)和聚乙烯(PE)上合成了纳米银颗粒薄膜,系统研究了该薄膜制备工艺、结构特性、材料性能之间的关系。实验考察了材料“浸泡”时间及聚合物材料前处理等因素对材料表面吸附纳米颗粒含量的影响,研究了 “浸泡”时间对纳米银颗粒粒径大小、颗粒含量及分布的影响,并探讨了不同聚合物基体的颗粒特性对薄膜二维导电渗滤,压阻特性及拉伸性能的影响。研究表明,增加“浸泡”时间能够增加纳米银颗粒粒径大小,提高银颗粒的含量及分布均匀性；在相同的制备条件下,PI基底较PE基底对纳米银颗粒具有更加优异的吸附效果；在PI 和PE基底上的纳米银颗粒薄膜均表现出显著的压阻性能,且电阻对应变的敏感性随应变的增大及银颗粒含量的减少而显著提高。     

Optimization of gliclazide loaded alginate-gelatin beads employing central composite design

Abstract

Objective: The aim of this study was to optimize the formulation of alginate-gelatin (AL-GL) beads containing gliclazide (GLZ) employing design of experiments (DOE).

Significance: DOE enabled identification of the interaction between the studied factors, deep understanding of GLZ release pattern and acceleration of the optimization process.

Methods: A three-factor, three-level face centered design was employed. The effects of GLZ content (GLZ%, X₁), polymer ratio (AL:GL ratio, X₂), crosslinker concentration (glutaraldehyde, GA%, X₃), and their interaction on incorporation efficiency (IE) and release rate were studied. The optimized formulation was prepared using numerical optimization and evaluated by DSC, FT-IR, SEM and release rate studies.

Results: Increasing GA% (X₃) decreased IE (Y₁) with the highest magnitude of effect among the studied factors. On the other hand, increasing alginate content in AL:GL ratio (X₂) increased IE (Y₁). The amount of GLZ released Q_0.5h, Q_2h(pH 1.2) and Q_4h(pH 7.4) decreased by increasing GLZ% (X₁) and AL:GL ratio (X₂). Both drug content and AL:GL ratio appeared to affect water penetration into the gel matrix and drug release. Generally, there was a direct relationship between GA% (X₃) and GLZ release in pH 1.2 (Q_0.5h and Q_2h). However, in pH 7.4 (Q_4h), increasing GA% decreased GLZ release. In addition, increasing GA% caused deviation from zero-order release model. The actual responses of the optimized formulation were in close agreement with the predicted ones.

Conclusion: The selected factors and their levels studied in the optimization design were useful for tailoring the anticipated formulation characteristics and GLZ release pattern.     

Preparation of novel polysulfone capsules containing zirconium phosphate and their properties for Pb2+ removal from aqueous solution

Zirconium phosphate (ZrP) was immobilized by microencapsulation process of polysulfone (PSF) to form the polysulfone capsules containing ZrP (PSF@ZrP capsules) successfully by using phase inversion precipitation technique, and the PSF@ZrP was employed as capsules adsorbents to remove Pb(2+) presented in aqueous solution. The result shows that an encapsulation capacity of 50% (mass ratio, PSF: ZrP = 1:1) should be the optimal proportion of ZrP encapsulated with PSF. The characterization of the macroscopical and microcosmic physical properties of the resulting PSF@ZrP capsules was carried out by the DTA-TG, XRD, BET and SEM. Meanwhile, the adsorption properties of the PSF@ZrP capsules for Pb(2+) were investigated by batch methods. It was found that the adsorption of the PSF@ZrP capsules for Pb(2+) would be pH dependent due to the ion-exchange mechanism, and the uptake of Pb(2+) was slightly influenced with the concentration of coexisting cations (Na(+), K(+)) in a low range. Furthermore, the calculated thermodynamics parameters exhibit that the nature of the adsorption process is spontaneous and exothermic. After six times of adsorption-regeneration cycles, no significant loss of adsorption capacity was observed, indicating the good stability of the PSF@ZrP capsules. Consequently, the PSF@ZrP capsules in this work can provide a potential application for treatment process of Pb(2+)-containing wastewater.     

聚吡咯/氧化石墨复合材料的制备及其电容性能

以氧化石墨为载体,采用木质素磺酸钠作为掺杂剂,氯化铁作为氧化剂,引发吡咯单体在氧化石墨层发生化学原位聚合反应,制备了聚吡咯(PPy)/氧化石墨复合材料。通过XRD、FTIR和SEM分析分别对复合材料的物相组成、结构和微观形貌进行了表征,通过TGA分析研究了复合材料的热稳定性,采用恒电流充放电、循环伏安和电化学阻抗谱等方法测试分析其电化学性能。研究表明:采用化学原位聚合的方法合成的PPy/氧化石墨复合材料具有"层-球"状的"三明治"型微观结构,以便形成良好的导电网络,其结晶度高、排列规整、缺陷少,复合材料中吡咯单体通过N-H键与氧化石墨的含氧官能团发生键合。PPy/氧化石墨复合材料新颖的微观结构和良好的化学键合状态使其表现出优异的电容性能。在电流密度分别为0.5、1.0、2.0和5.0 A/g时的比电容分别为500、460、427和396 F/g;经过1000次恒电流(2.0 A/g)充放电循环后, PPy/氧化石墨复合材料的比电容保持率为97.2%。      

疏水磁性碳酸钙的制备及其除油特性EI北大核心CSCD

以硬脂酸为疏水改性剂,将其与Fe_(3)O_(4)纳米颗粒和市售CaCO_(3)共混,分别以不同的原料质量比,制备疏水磁性碳酸钙HMC-1和HMC-2,并将HMC-2负载在PU海绵上用以提高其实用性能。采用X射线粉末衍射仪、红外光谱仪、差示扫描量热仪、接触角/表界面张力测量仪对合成样品的物相、表面有机官能团、热稳定性及疏水性能进行系列表征分析。结果表明,HMC-2比HMC-1,具有更稳定的疏水性能,除油前后水接触角基本保持不变,约为150°,除油后该材料没有出现类似HMC-1的铁渗出现象。将HMC-2负载在PU海绵上后,改性PU海绵在3 s内可去除98%的油,重复吸油20次仍能达到95%以上的除油率,吸油倍率(吸附油质量/吸附剂质量)大于100。     

N掺杂TiO2陶瓷膜的制备及其光催化性能研究

采用溶胶-凝胶法制备N掺杂TiO2溶胶,用浸渍-提拉方法将溶胶涂敷在陶瓷膜表面,制备具有抗污染性能的光催化陶瓷膜。光催化与膜分离技术相结合,处理含盐直接耐酸大红4BS染料废水,考察了料液pH值、初始浓度、跨膜压差、膜面流速等因素对含盐染料废水处理效果的影响。结果表明,该复合陶瓷膜对4BS染料的截留率在99%以上,对无机盐的截留率低于1%,光催化膜分离耦合的膜通量较单一膜分离的通量提高90%。