石墨烯负载纳米银的制备及其对H2O2的电化学检测

采用改进的Hummers法制备了氧化石墨烯（GO）,然后以水合肼作为还原剂,并控制反应的pH=10来制备还原氧化石墨烯（RGO）。采用化学还原法,以石墨烯为载体,以乙酰丙酮银为前体,以硼氢化锂四氢呋喃溶液为还原剂将银离子还原,制备了石墨烯负载纳米银复合材料。通过X 射线粉末衍射（XRD）、傅里叶变换红外光谱（FTIR）和透射电子显微镜（TEM）等表征方法证明了石墨烯上负载的银纳米颗粒结晶良好、尺寸均一、分布均匀,其中银纳米颗粒直径约为8nm。通过循环伏安和计时电流技术对石墨烯负载纳米银复合材料进行电化学测试,结果表明,石墨烯负载纳米银复合材料对过氧化氢的还原具有良好的电催化活性。以此复合纳米结构构建的过氧化氢传感器测试过氧化氢浓度的线性范围为0.1～62.3mmol/L（R=0.990）,检出限为0.017mmol/L（S/N=3）,响应时间小于2s。     

黑曲霉负载银纳米颗粒的制备及其抗菌性能

采用非酶还原法,以黑曲霉菌原位还原银氨离子制备一种新型银纳米颗粒（AgNPs）/菌体复合抗菌材料,着重考察了反应温度与pH值对还原过程和所得复合材料的抗菌性能及稳定性的影响。结果表明,在温度为30℃、60℃和pH 9.5、11.5条件下,能够合成出粒径为6.9～8.2 nm的近球形AgNPs。该AgNPs均匀地分布在菌体表面上,对E.coli显示出高的抗菌性能：最小抑菌浓度(MIC)为217～434 mg·L^-1（以菌粉总质量表示）或8～20 mg Ag·L^-1（以银含量表示）。提高反应温度有利于提高菌体银负载量,但AgNPs粒径增大,抗菌性能有所下降;提高反应pH值有利于提高还原速率,而对抗菌性能影响不显著。复合材料中AgNPs与菌体结合牢固,单位质量复合材料释出的Ag⁺含量为1.7～6.8 mg·g^-1,提高反应温度和pH值后Ag⁺的释出均减少。     

还原氧化石墨烯负载纳米银/聚乙烯醇型抗菌水凝胶的制备与性能

以聚乙烯醇（PVA）、氧化石墨烯（GO）、硝酸银为原料,在不添加引发剂和交联剂的情况下,使用物理交联法（冷冻-解冻法）制得了一系列还原氧化石墨烯（rGO）负载不同质量分数纳米银（AgNPs）/PVA型抗菌水凝胶（rGO-AgNPs/PVA）(PGA-1～PGA-6,阿拉伯数字代表AgNPs的质量分数)。通过FTIR、SEM、TGA、电子万能材料试验机和流变仪对水凝胶的结构、形貌、力学性能和流变性能进行了表征,并对其生物性能进行了测试。结果表明,rGO的加入增强了PVA水凝胶的机械强度,rGO-AgNPs/PVA抗菌水凝胶断裂伸长率比PVA水凝胶提高约60%,拉伸应变达到125%。PVA水凝胶的储能模量和损耗模量均低于rGO-AgNPs/PVA水凝胶;rGO与AgNPs协同抗菌,PGA-3(AgNPs质量分数0.33%)对大肠杆菌和金黄色葡萄球菌的抑菌带宽度分别约为4.5和5.5 mm;相较于PVA水凝胶,rGO-AgNPs/PVA水凝胶的孔洞增多,r GO通过π-π作用形成网络结构,r GO-Ag NPs/PVA水凝胶显示出多孔互联的微观结构。     

纳米银@石墨烯复合材料的绿色制备及其抑菌性能

以聚乙二醇为还原剂通过水热反应,还原氧化石墨烯同时在石墨烯表面原位生长银纳米粒子,制备纳米银@石墨烯复合材料。采用紫外-可见吸收光谱、X射线衍射、红外吸收光谱、透射电子显微镜对所制备的纳米银@石墨烯复合材料进行了表征。结果表明,银以单质形态成功负载在石墨烯表面,银纳米粒子的平均粒径为30nm。以大肠杆菌为模型对纳米复合材料的抑菌性能进行测试,纳米银@石墨烯复合材料在100 mg/L时可以完全抑制大肠杆菌的生长,是一种效果显著的新型抑菌材料。     

氧化石墨烯负载纳米银/聚乙烯醇型抗菌水凝胶制备与性能

以聚乙烯醇(PVA)、氧化石墨烯(GO)、硝酸银为原料，在不添加引发剂和交联剂的情况下，使用物理交联法（冷冻-解冻法）制得系列AgNPs质量分数不同的还原氧化石墨烯（rGO）负载纳米银/聚乙烯醇型抗菌水凝胶（rGO-AgNPs/PVA）（PGA）。通过FTIR、SEM对水凝胶的结构和形貌进行了表征，通过拉力实验和生物实验对其力学性能和生物性能进行了测试。结果表明，还原氧化石墨烯的加入增强了聚乙烯醇（PVA）水凝胶的机械强度，rGO-AgNPs/PVA抗菌水凝胶断裂伸长率相较于PVA水凝胶提高约60%，拉伸应变可达到125%。流变测试表明，PVA水凝胶的储能模量（G''）和损耗模量（G''）均低于rGO-AgNPs/PVA水凝胶；rGO与纳米银(AgNPs)协同抗菌，PGA-1、PGA-2、PGA-3、PGA-4、PGA-5对大肠杆菌和金黄色葡萄球菌的抑菌带宽度分别为0.5~4.5 mm和0.5~5.5 mm；SEM测试发现，相较于PVA水凝胶，rGO-AgNPs/PVA水凝胶的孔洞增多，rGO通过π-π作用形成网络结构，rGO-AgNPs/PVA水凝胶显示出多孔互联的微观结构。     

基于白藜芦醇还原特性的银基纳米载体制备及肿瘤细胞杀伤效应评价

以反式白藜芦醇(resveratrol,RES)为还原剂,硝酸银(AgNO_3)为前驱体,十六烷基三甲基溴化铵(cetyltrimethylammonium bromide,CTAB)为表面活性剂和相转移催化剂,采用原位液相还原工艺制备了负载RES的银基纳米载体(RES-AgNPs)。当AgNO_3、RES和CTAB摩尔比为1:1:0.5、40℃反应13 h时,制得平均粒径(45.5±2)nm、zeta电位-21 mV的RES-AgNPs。红外光谱和紫外吸收光谱分析结果表明,RES成功负载在纳米银表面,负载量达到0.0883 mg?mg~(-1)。体外释放实验表明,RES-AgNPs具有过氧化氢(H_2O_2)敏感响应的释放特性,当p H=5.4且CH_2O_2=25μmol?L~(-1)时RES释放率为89%。以人乳腺癌细胞MCF-7为肿瘤细胞模型,MTT实验结果显示,当样品剂量均为15μg?mL~(-1)时,与RES、AgNPs和RES+AgNPs联合给药相比,RES-AgNPs对细胞的生长抑制率分别提高了62.6%、68.2%和55.1%,体现了纳米载体中银纳米粒子与负载药物RES对肿瘤细胞的协同杀伤效应。     

天然产物绿色合成小尺寸纳米银及抗菌性

利用液相化学还原法,以硝酸银作前驱体,采用天然产物壳聚糖和葡萄糖分别作稳定剂和还原剂制备了小尺寸的球形纳米银(AgNPs)。运用紫外-可见分光光度计(UV-vis)、透射电子显微镜(TEM)和X射线衍射(XRD)技术对一系列AgNPs样品进行了表征,并考察了稳定剂、前驱体和还原剂的浓度、pH、反应温度和时间等制备条件对AgNPs成核或生长过程的影响。通过调节制备条件可调控AgNPs的尺寸分布,得到粒径分别为(3±1)nm、(6±2)nm和(9±3)nm分散均匀且稳定的AgNPs。采用OD600法对AgNPs的抗菌性进行了测试,结果表明,AgNPs对大肠杆菌(E.coil)和金黄色葡萄糖球菌(S.aureus)都有很好的抑制作用。     

纳米银氧化石墨烯复合修饰电极检测环丙沙星

利用浸渍法结合电化学还原法制备了纳米银石墨烯复合修饰电极(AgNPs/RGO/GCE),利用扫描电镜(SEM)观察了AgNPs/RGO/GCE的表面结构,采用循环伏安法(CV)表征了修饰电极的电化学性能,研究了盐酸环丙沙星(CIP)在AgNPs/RGO/GCE上的电化学行为,并在此基础上选用微分脉冲伏安法(DPV)探讨了AgNPs/RGO/GCE检测CIP的可行性。结果表明,AgNPs/RGO/GCE对CIP的电化学氧化具有非常明显的催化作用,在最优实验条件下,该方法灵敏度高、重复性和稳定性好,对模拟水样检测的回收率在96. 34%～107. 2%之间,RSD为2. 015%～3. 342%。     

AgNPs/TPU导电纤维的制备及性能研究

以热塑性聚氨酯(TPU)为弹性纤维基体，三氟乙酸银(C₂AgF₃O₂)为导电银纳米粒子(AgNPs)前驱体，水合肼为还原剂，采用湿法纺丝工艺、原位还原技术及热处理制备AgNPs/TPU导电纤维，研究了水合肼浓度、还原时间、C₂AgF₃O₂含量、热处理对纤维导电性能的影响，并对其微观形貌、化学组成、力学性能、拉伸电阻敏感性进行表征。结果表明：在C₂AgF₃O₂/TPU质量比为1.5：1.0,水合肼质量分数为15%,还原时间为20 min, 120℃热处理30 min的条件下得到的AgNPs/TPU导电纤维具有最佳的导电性能，电导率可达108.9 S/cm; AgNPs/TPU导电纤维微观上呈中空多孔结构，纤维表面被AgNPs均匀覆盖；AgNPs/TPU导电纤维的力学性能相比纯TPU纤维有所降低，断裂伸长率为484%,断裂强度为0.15 cN/dtex;该纤维可在0～70%的应变范围内表现出较为...     

芳樟叶浸出液还原制备对硝基苯酚加氢银催化剂

采用芳樟叶浸出液,通过原位还原和等体积浸渍的方法制备负载型纳米银催化剂,并以对硝基苯酚(4-NP)加氢反应为模型反应,考察催化剂载体,焙烧条件等对负载型纳米银催化剂性能的影响,并采用扫描电镜(SEM),热重分析(TG)和红外光谱( FT-IR)等表征手段对催化剂进行表征.结果表明,以TiO2为载体制备的纳米银催化剂具有...     

Poly(acrylic acid) hydrogel microparticles fabricated with silver nanoparticles: synthesis,characterization, and catalytic applications

This work narrates the synthesis of poly (acrylic acid) hydrogel microparticles (PAAHMPs), fabrication of silver nanoparticles (AgNPs) inside the structure of the prepared PAAHMPs and catalytic applications of PAAHMPs fabricated with AgNPs (PAAHMPs/AgNPs). The PAAHMPs were prepared by inverse suspension polymerization technique while fabrication of AgNPs was carried out by chemical reduction method using sodium borohydride (NaBH₄) as reducing agent. The identification of functional groups in bare PAAHMPs and in the PAAHMPs/AgNPs composite system was carried out by the Fourier transform infrared spectroscopy. The size and morphology of the prepared hydrogel and its composite was studied by scanning electron microscopy and transmission electron microscopy. X-ray diffraction and thermal gravimetric analyzer was also used to characterize the bare PAAHMPs and PAAHMPs/AgNPs composite. The prepared PAAHMPs/AgNPs composite was used as catalyst for the reduction of nitro aromatic pollutants and an industrial dye, that is, 4-Nitrophenol (4-NP), 2-Nitrophenol (2-NP) and methyl orange. No loss in catalytic activity was noted in seven consecutive cycles of recycling process while only 37.5% loss in catalytic activity was observed upon storing the catalyst for 90 days.     

Synthesis of novel poly(1-naphthylamine)-silver nanocomposites and its catalytic studies on reduction of 4-nitrophenol and methylene blue

A novel poly(1-naphthylamine)-silver (PNA-Ag) nanocomposite has been prepared and used as a heterogeneous catalyst for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB). In this study, silver nanoparticles (AgNPs) have been incorporated to PNA via a simple and fast one-step route, where PNA acts as the reductant for silver ions and stabilizer for AgNPs. The prepared PNA-Ag nanocomposites were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy dispersive X-ray scattering (EDAX), and Fourier transform infrared (FTIR) spectroscopy. They provided ample evidence for the anchoring of AgNPs to the PNA chains. Enhanced electrochemical performance of the PNA-Ag nanocomposite has been evidenced by cyclic voltammetry studies. Catalytic studies confirmed that the rate of reduction of both 4-NP and MB with sodium borohydride have been enhanced significantly in the presence of AgNPs loaded PNA in comparison to neat PNA. This nanocomposite could find application as catalyst for reductive degradation of toxic organic pollutants. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48318.     

Vinyl polysiloxane microencapsulated ammonium polyphosphate and its application in flame retardant polypropylene

Vinyl polysiloxane microencapsulated ammonium polyphosphate (MAPP) was prepared by a sol-gel method using vinyltrimethoxysilane as a precursor to improve its thermal stability and hydrophobicity. The MAPP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and thermogravimetric analyzer (TGA). The results showed that ammonium polyphosphate (APP) was successfully coated with vinyl polysiloxane. MAPP and pentaerythritol (PER) were used together to improve the flame retardancy of polypropylene (PP). The flame retardant properties of PP composites were investigated by limiting oxygen index (LOI), UL-94 test, TGA and SEM. When the MAPP was added as a flame retardant, with PER as a char forming agent, the LOI of PP/MAPP/PER composites was 33.1%, and it reached the UL-94 V-0 level. The results also demonstrated that the flame retardant properties of PP/MAPP/PER composites were better than those of PP/APP/PER composites at the same loading. Moreover, the addition of flame retardant and carbon forming agent could promote the crystallization behavior of PP.     

Performance assessment of poly (methacrylic acid)/silver nanoparticles composite as corrosion inhibitor for aluminium in acidic environment

This article reports the preparation of poly (methacrylic acid)/silver nanoparticles composite (PMAA/AgNPs) by in situ mixing of aqueous solutions of PMAA and 1 mM AgNO₃ with natural honey as reducing and stabilizing agent. The prepared PMAA/AgNPs composite was characterized by UV–vis spectroscopy, Fourier transformed infrared, X-ray diffraction and energy dispersive spectroscopy (EDS) while the morphology of the AgNPs in the composite was obtained by transmission electron microscopy (TEM). TEM results revealed that the AgNPs were spherical in shape. The performance of PMAA/AgNPs composite as anticorrosion material for Al in acidic environment was examined by electrochemical, weight loss methods, complemented by surface analysis characterization with scanning electron microscopy (SEM), EDS and water contact angle measurements. Results obtained indicate that PMAA/AgNPs composite is effective corrosion inhibitor for Al in an acid-induced corrosive environment. Inhibition efficiency increased with increase in composite concentration but decreased with rise in temperature. From potentiodynamic polarization results, PMAA/AgNPs composite is found to function as a mixed-type corrosion inhibitor. The adsorption of the composite onto Al surface was found to follow El-Awady et al. adsorption isotherm model. SEM, EDS and water contact angle results confirmed the adsorption of the composite on Al surface.     

Facile preparation of silver/reduced graphene oxide/chitosan colloid and application of the nanocomposite in antibacterial and catalytic activity

Reduced graphene oxide (RGO) decorated with silver nanoparticles (AgNPs) was synthesized by a facile solution‐based approach in chitosan (CS) solution. The morphology and elemental composition of as‐prepared Ag/RGO/CS colloid were characterized by SEM and energy dispersive X‐ray spectroscopy, respectively. TEM images show that most of the AgNPs are uniformly dispersed in the CS matrix while the other nanoparticles are decorated on the RGO nanosheets. XRD indicates that the interlayer distance of RGO is between 0.34 and 1.87 nm while the diameter of face‐centered cubic AgNPs is no more than 30 nm. Fourier transform infrared spectroscopy of the Ag/RGO/CS colloid confirms the formation of AgNPs and RGO. X‐ray photoelectron spectroscopy proves that both the Ag ? O bond and the C ? N bond exist in the nanocomposite. Antimicrobial assays were performed using the most common species of Gram bacteria. The inhibitory effect indicates that the incorporation of AgNPs and RGO significantly improves the antimicrobial activity of CS colloid. In addition, the nanocomposite colloid exhibits significant catalytic activity toward the reduction of 4‐nitrophenol by NaBH₄. © 2018 Society of Chemical Industry     

Preparation and characterization of ceramic composites derived from rice husk ash and polysiloxane

Ceramic matrix composites (CMCs) were prepared from a polysiloxane network filled with rice husk ash (RHA), a reactive filler. CMCs were obtained by pyrolysis at 1000 and 1600 °C of green bodies prepared from a mixture of polysiloxane network and RHA at a weight ratio of 4:1, respectively. The RHA and the CMCs were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS), in addition to density and mechanical measurements. The CMCs were obtained without macroscopic defects, and their initial observed porosity was reduced by polymeric infiltrations cycles of the polymeric precursor, which improved their flexural strength and modulus up to 100%.     

Synergistic effects of 4A zeolite on the flame‐retardant properties and thermal stability of an efficient halogen‐free flame‐retardant EVA composite

The synergistic effects of 4A zeolite (4A) on the thermal degradation, flame retardancy, and char formation of an efficient halogen‐free flame‐retardant ethylene‐vinyl acetate copolymer composite (EVA/IFR) were investigated by limited oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter test (CCT), digital photography, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), laser Raman spectroscopy (LRS) and thermogravimetric analytical (TGA) methods. It was found that a small amount of 4A clearly improved the LOI value of the EVA/IFR composite and reinforced the fire retardant performance with a great reduction in the combustion parameters of the EVA/IFR system from the CCT test. The entire composites passed the UL‐94 V‐0 rating test. The TGA and integral procedure decomposition temperature (IDPT) results showed that 4A enhanced the thermal stability of the EVA/IFR system and increased the char residue content effectively. The morphological structures observed by digital and SEM imaging revealed that 4A could promote EVA/IFR to form a more continuous and compact intumescent char layer. The LRS and EDS results demonstrated that by introduction of 4A into the EVA/IFR system, a more graphite structure was formed with increase phosphorus content in the char residue. POLYM. ENG. SCI., 56:380–387, 2016. © 2016 Society of Plastics Engineers     

Apo/PbSe复合材料的制备及其光催化性能

利用脱铁铁蛋白制备的纳米材料具有尺寸可控、单一等优点,在催化方面同样具有很大优势。本文以脱铁铁蛋白为模板,硒脲为硒源,乙酸铵与乙酸铅为原料,通过模板合成法和两步法制备脱铁铁蛋白/硒化铅(apo/PbSe)复合材料,采用透射电子显微镜(TEM)、X射线衍射仪(XRD)、X射线能谱仪(EDS)、紫外-可见分光光度计(UV-vis)、荧光光谱仪(PL)等手段分析材料,并测定了apo/PbSe复合材料在可见光下对废水染料甲基橙的催化降解性能。结果表明,蛋白质内部的矿物核心主要物质为PbSe,成功合成了apo/PbSe复合光催化剂。复合光催化剂的最佳实验条件为溶液pH=3.0,H₂O₂质量分数9%,此时对甲基橙的降解效率最高可达97.10%,五次循环降解实验证明了其光催化效率的稳定性。基于以上结果,说明apo/PbSe具有良好的催化活性和稳定性,并提出了apo/PbSe复合材料对甲基橙的光催化降解机理。     

Fire retardant synergism of hydroquinone bis(diphenyl phosphate) and novolac phenol in acrylonitrile–butadiene–styrene copolymer

Hydroquinone bis(diphenyl phosphate) (HDP) has been adopted to prepare acrylonitrile–butadiene–styrene copolymer (ABS)/HDP/novolac phenol (NP) composites. The limiting oxygen index (LOI) of ABS/HDP/NP composites is tested in this paper. The LOI value first grows with increasing ratio of HDP to NP, after reaching its maximum it decrease with further increasing ratio. The synergistic effect of HDP and NP exerted on the microstructure and the flame retardancy of ABS/HDP/NP composites are carefully analyzed by thermogravimetric analysis (TGA), cone calorimeter (CCT), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The results of CCT show that the synergistic action of HDP and NP reduces its heat release rate and smoke production rate. The results of TGA and SEM demonstrated that the introduction of NP and HDP is conducive to the improvement of the thermal stability and the formation of the intumescent char with homogeneous cavities and holes. The EDS results indicate that the introduction of NP could help retain phosphorus in the chars. As a result, the synergistic action of HDP and NP is favorable to the enhancement of flame retardancy of ABS/HDP/NP composites. Copyright © 2014 John Wiley & Sons, Ltd.     

苯基聚硅氧烷微胶囊化聚磷酸铵的制备及其在PP中阻燃性能研究

采用苯基三甲氧基硅烷为前驱体,通过溶胶凝胶法制备出苯基聚硅氧烷微胶囊化聚磷酸铵（MAPP）。将MAPP作为阻燃剂,季戊四醇（PER）作为成炭剂,制备阻燃聚丙烯（PP）。用傅里叶红外光谱、扫描电子显微镜、能谱仪及热重分析仪对MAPP进行表征。结果表明,聚磷酸铵（APP）被苯基聚硅氧烷成功包覆;较之APP,MAPP的热稳定性和疏水性显著提高;MAPP的阻燃性能优于APP,PP/MAPP/PER复合材料达到V-0级别;阻燃剂及成炭剂的加入对PP的结晶行为有促进作用。