溶胶凝胶法制备nAl/CuO纳米复合材料

发展了碱性催化sol-gel方法,以尿素为碱性催化剂,基于三水合硝酸铜[Cu(NO_3)_2·3H_2O]和纳米铝粉制备了nAl/CuO纳米复合材料。使用红外光谱(FIIR)、X射线衍射(XRD)、差热分析(DSC)、扫描电子显微镜(SEM)表征了所得纳米复合材料的化学组成、形貌和能量释放特性。结果表明,弱碱性环境下sol-gel法制备的nAl/CuO体系具有典型的凝胶网络结构,nAl能在CuO凝胶中稳定、均匀分散,碱性sol-gel法有利于改善nAl/CuO的混合。DSC测试nAl/CuO纳米复合材料放热量为1 018 J/g,达到其理论热焓(4 077 J/g)的25%。     

溶胶凝胶法制备nAl/CuO纳米复合材料

发展了碱性催化sol-gel方法,以尿素为碱性催化剂,基于三水合硝酸铜[Cu(NO_3)_2·3H_2O]和纳米铝粉制备了nAl/CuO纳米复合材料。使用红外光谱(FIIR)、X射线衍射(XRD)、差热分析(DSC)、扫描电子显微镜(SEM)表征了所得纳米复合材料的化学组成、形貌和能量释放特性。结果表明,弱碱性环境下sol-gel法制备的nAl/CuO体系具有典型的凝胶网络结构,nAl能在CuO凝胶中稳定、均匀分散,碱性sol-gel法有利于改善nAl/CuO的混合。DSC测试nAl/CuO纳米复合材料放热量为1 018 J/g,达到其理论热焓(4 077 J/g)的25%。     

纳米Cu-Cr复合金属氧化物的机械研磨制备及对AP的催化性能

为了增强纳米氧化铜对高氯酸铵(AP)热分解的催化作用,采用机械研磨法批量制备了一系列摩尔比分别为1∶2, 1∶1, 1∶0.5, 1∶0.25的CuO/Cr_2O_3纳米Cu-Cr复合金属氧化物(纳米CuO/Cr_2O_3);采用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征样品的微结构、表面元素和形态;通过热重(TG)分析和差示扫描量热(DSC)技术研究了纳米Cu-Cr复合金属氧化物对AP热分解的催化作用,讨论了纳米CuO/Cr_2O_3含量对AP热分解的影响。结果表明,与其他纳米Cu-Cr复合金属氧化物、单一纳米CuO和纳米Cr_2O_3相比,质量分数2%的CuO/Cr_2O_3(摩尔比1∶0.25)复合金属氧化物对AP热分解具有最佳催化效果,可使AP的分解温度从441.3℃下降到351.1℃,吉布斯自由能从199.8kJ/mol降至172.1kJ/mol,同时表观分解热从941J/g升至1778J/g,这可能是由于在高能研磨力场下,纳米CuO和纳米Cr_2O_3发生晶格变化促进其对AP热分解的协同催化作用。     

新型电泳法制备纳米Al/(Fe_2O_3)Ⅲ含能薄膜

采用新新型电泳组装法成功制备含能纳米铝热剂Al/(Fe_2O_3)Ⅲ,采用扫描电镜等技术对铝热剂薄膜的微观形貌进行了分析。并通过对比差示扫描量热法等对铝热剂放热性能进行探究。结果表明:场强为20V/mm下,选用聚乙烯亚胺和聚乙烯胺为混合改性剂可以成功实现样品的电泳组装,并且含能薄膜相对均匀,无大量聚团出现。体系的Zeta电位约为70,说明悬浮体系稳定性高。此外,纳米Al/Fe_2O_3铝热剂薄膜放热量达到4.32MJ/kg,说明产品具有极强的热量输出能力。     

氰酸酯树脂/纳米氧化铜复合材料制备及性能

将无机纳米氧化铜(CuO)粒子加入氰酸酯树脂(CE),以有机锡(DBTDL)实现自由基引发,定量加入环氧树脂(E–54)制得CE/CuO系列复合材料。测试了复合材料的力学性能、导热性能和耐酸碱腐蚀性能,讨论了复合材料性能得以改变的原因。结果表明,无机纳米CuO粒子的引入,有利于CE基体树脂的聚合,无机纳米CuO粒子含量为10.0%时,复合材料差示扫描量热峰顶温度由286.3℃降至223.6℃,下降21.9%;无机纳米CuO粒子质量分数为6.0%时,复合材料弯曲强度达到165.36 MPa,较纯CE基体树脂提高了95.34%,复合材料冲击强度达14.18 kJ/m²,较纯CE基体树脂提高了62.24%;随无机纳米CuO粒子含量的增加,复合材料导热性能得以改善,当无机纳米CuO粒子含量为10.0%时,复合材料热导率增大10.24倍;无机纳米CuO粒子引入量为7.0%时,复合材料强碱腐蚀率为0.155%,比纯CE基体树脂下降38.0%;复合材料强酸腐蚀率为0.072%,比纯CE基体树脂下降60.4%。     

硬脂酸/活化凹凸棒石复合相变储热材料的制备与表征

以热活化的甘肃临泽凹凸棒石为基体,采用热熔法和浸渍法制备了硬脂酸/活化凹凸棒石复合相变储热材料。利用红外光谱仪(FTIR)、X射线衍射仪(XRD)和扫描电子显微镜(SEM)等方法表征了复合材料的结构,采用示差量热扫描仪(DSC)和储放热实验考察了复合材料的储/放性能和稳定性。结果表明采用热熔法和溶液浸渍法制备的材料具有相同的结构,硬脂酸按38.5%的负载率以物理作用吸附于活化凹凸棒石表面,其相应的相变焓分别为68.44 J/g和69.06 J/g。稳定性实验表明2种材料均具有良好的化学稳定性,但热稳定性存在差异,热熔法制备的复合材料的热稳定性优于浸渍法制备的复合材料。     

CE/EP/纳米SiC复合材料研究

采用纳米SiC和环氧树脂(EP)对双酚A型氰酸酯树脂(CE)进行改性。研究了不同含量的纳米SiC对CE/EP/纳米SiC复合体系反应性及CE/EP/纳米SiC复合材料力学性能的影响,采用透射电子显微镜表征了材料的微观形貌,利用差示扫描量热法研究了固化树脂的热性能。结果表明,纳米SiC对CE/EP/纳米SiC复合体系具有明显的催化作用,并且能使复合材料的冲击强度提高123.62%,弯曲强度提高140.29%,有效发挥其增强增韧作用,还能很好地保持复合材料的耐热性能。     

单体接枝PP包覆纳米CaCO3对PP结晶动力学的影响

采用不同单体接枝聚丙烯(PP)包覆纳米CaCO3与PP复合制备PP/纳米CaCO3复合材料,用差示扫描量热法研究了复合材料中PP的等温和非等温结晶动力学。研究结果表明,不同单体接枝PP包覆纳米CaCO3填充PP复合材料中PP的结晶温度取决于单体类型。PP复合材料的结晶速率高低顺序依次为马来酸酐,丙烯酸丁酯,丙烯酸(或苯乙烯),PP。结晶速率快的复合材料具有低的结晶活化能。     

Al@GAP复合粒子对LLM-105热分解性能的影响

为防止铝粉在存储中氧化失活,同时为含铝炸药配方设计提供借鉴,采用聚叠氮缩水甘油醚(GAP)对不同尺寸Al粉(平均粒径分别为50nm和1~2μm)进行包覆改性,获得Al@GAP复合粒子;采用扫描电镜(SEM)、透射电镜(TEM)表征其形貌;用差示扫描量热法(DSC)对不同质量比的(Al@GAP)/LLM-105混合体系的热分解过程进行了研究。结果表明,采用两步包覆法获得了不同尺寸Al粉表面包覆GAP的核壳结构复合粒子;相较于包覆前的微米级Al粉,加入GAP包覆的纳米Al粉后混合体系的热分解峰温明显降低;当Al粉质量分数大于10%时,GAP包覆后的(Al@GAP)/LLM-105混合体系的熵变(ΔS~≠)和焓变(ΔH~≠)较Al/LLM-105混合体系有所减小;(Al@GAP)/LLM-105混合体系的活化能、热爆炸临界温度及热力学参数ΔS~≠和ΔH~≠随纳米Al粉含量的增加而降低,当Al粉质量分数为30%时,较LLM-105分别降低4kJ/mol、3℃、4.3J/(mol·K)、4.2kJ/mol。     

纳米SiO2包覆SiC填充改性UHMWPE的热性能

采用纳米粒子表面包覆处理技术制备了纳米碳化硅/超高摩尔质量聚乙烯(SiC/UHMWPE)复合材料,并用傅立叶红外光谱(FTIR)、扫描电镜(SEM)、透射电镜(TEM)、热重分析(TG)和差示扫描量热(DSC)进行了测试表征。结果表明:纳米SiC经包覆处理后表面有一层均匀致密的SiO2,包覆处理能改善SiC在UHMWPE基体中的分散效果。当SiC质量分数为5%时,UHMWPE/SiC复合材料具有较高的耐热性能和热导率,这是由于纳米粒子包覆改性纳米SiC与UHMWPE基体均匀分散并形成良好的结合界面,增加了填料对UHMWPE的成核作用,提高其结晶度和耐热性能。     

Thermal behavior of Al/MoO3 xerogel nanocomposites

Sol–gel process using molybdenum alkoxides was employed to prepare Al/MoO₃ xerogel nanocomposites as a thermite with better performance by improvement of interfacial contact area between the oxidizer and fuel. Micromorphology and thermite reaction characteristics of Al/MoO₃ xerogel nanocomposites were analyzed by scanning electron microscopy (SEM) and thermogravimetry/differential scanning calorimetry (TG/DSC), respectively. In the present Al/MoO₃ xerogel system, it was found that exothermic enthalpy increases as the Al/Mo mole ratio increases and then decreases when Al/Mo mole ratio is larger than 6 indicating that optimum mole ratio of Al/Mo is 6 with reaction enthalpy of 420.58 J/g.     

Synthesis and characterization of novel polyimide/SiO2 nanocomposite materials containing phenylphosphine oxide via sol‐gel technique

In this article, a series of novel polyimide/silica (PI/SiO₂) nanocomposite coating materials were prepared from tetraethoxysilane (TEOS), γ‐glycidyloxypropyltrimethoxysilane (GOTMS), and polyamic acid (PAA) via sol‐gel technique. PAA was prepared by the reaction of 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride (BTDA) and bis (3‐aminophenyl) phenyphosphine oxide (BAPPO) in N‐methyl‐2‐ pyrrolidone (NMP). BAPPO was synthesized hydrogenation of bis (3‐nitrophenyl) phenyphosphine oxide (BNPPO) in the presence of Pd/C. The silica content in the hybrid coating materials was varied from 0 to 20 wt %. The molecular structures of the composite materials were analyzed by means of FT‐IR and ²⁹Si‐NMR spectroscopy techniques. The physical and mechanical properties of the nanocomposites were evaluated by various techniques such as, hardness, contact angle, and optical transmission and tensile tests. These measurements revealed that all the properties of the nanocomposite coatings were improved noticeable, by the addition of sol‐gel precursor into the coating formulation. Thermogravimetric analysis showed that the incorporation of sol‐gel precursor into the polyimide matrix leads to an enhancement in the thermal stability and also flame resistance properties of the coating material. The surface morphology of the hybrid coating was characterized by scanning electron microscopy (SEM). SEM studies indicated that nanometer‐scaled inorganic particles were homogenously dispersed throughout the polyimide matrix © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

相变微胶囊的制备及其在涂料中的应用研究

实验采用界面聚合法,以2,4-甲苯二异氰酸酯(TDI)与四乙烯五胺(TEPA)的反应物为壁材包覆硬脂酸丁酯制成聚脲微胶囊相变材料,同时对微胶囊进行了FTIR、DSC和SEM等性能检测。并将此自制微胶囊作为填料,添加到防锈涂料中,对其进行相应的性能检测及表征,结果表明:防锈涂料相变温度19.2℃,相变焓65.5 J/g,具有一定的调温性能。     

Carbon nanotube reinforced hydroxyapatite composite coatings produced through laser surface alloying

Carbon nanotube (CNT) reinforced hydroxyapatite composite coatings have been successfully fabricated by laser surface alloying. The phase compositions and the microstructure of the composite coatings were studied using X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). TEM observation showed that a large amount of CNTs can be found with their original tubular morphology in the composite coatings, even though some CNTs react with titanium element in the substrate during laser irradiation. Additionally, measurement on the elastic modulus, hardness of the composite coatings by nanoindentation tests indicated that the mechanical properties are affected by the amount of CNTs in the starting precursor materials. Therefore, CNT reinforced hydroxyapatite composite coating is a promising coating material for high-load-bearing metal implants.     

CuO/腐植酸复合材料的制备及其吸附性能

采用水热法合成了CuO-腐植酸（HA）纳米复合材料,研究了其对亚甲基蓝的初始吸附性能及再生吸附性能。运用扫描电镜/能谱仪（SEM/EDS）、傅里叶变换红外光谱仪（FTIR）、X射线粉末衍射仪（XRD）、激光粒度分析仪和比表面积测定仪（BET）对其结构进行了表征。研究了pH、亚甲基蓝初始浓度和反应温度等因素对CuO/HA吸附亚甲基蓝的影响,采用多种模型研究了CuO/HA复合材料对亚甲基蓝的吸附动力学和热力学行为。结果表明：合成的CuO/HA平均粒径约为135.0nm,比表面积为188.15m²/g。CuO/HA对亚甲基蓝（MB）的吸附动力学行为符合拟一级动力学模型,在60min内达到吸附平衡,较好地符合Frendlich吸附模型。在室温下pH=7时,CuO/HA复合材料初始饱和吸附量达172.01mg/g;循环使用8次,可保持初始吸附能力的89.27%,表明有较好的吸附性能,可作为一种有效除去水体中亚甲基蓝污染物的高容量吸附材料。     

Polystyrene/melamine-formaldehyde hollow microsphere composite by self-assembling of latex particles at emulsion droplet interface

Submicron scale particle aggregates with defined shape were prepared by self-assembling of sulphonated polystyrene latex particles at the interface of emulsion droplets. Several parameters were considered during the preparation, including the sulphonation time of the polystyrene latex particles, the composition of the oil phase, and the zeta potential of the sulphonated latex particle. To further improve the mechanical stability of the particle aggregates, a hard composite layer was formed by addition of melamine-formaldehyde (MF) prepolymer into the emulsion. The prepolymer was crosslinked onto the particles surface of sulphonated PS particle aggregates. The crosslinking reaction was catalysed by the acidity of sulfogroup. After evaporating off solvent, PS/MF hollow microsphere composites were obtained as mechanically stable dry material. The hollow microsphere composite was characterized by TGA, FTIR, optical microscopy, scanning and transmission electron microscopy.     

CuO@HHSS催化剂制备及催化还原对硝基苯酚性能

在水热合成复合二氧化硅空心球（HHSS）基础上,以硝酸铜为原料,采用超声辅助浸渍法制备出高分散CuO@HHSS复合催化剂。采用X射线衍射（XRD）、氮气吸附-脱附、X射线光电子能谱（XPS）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）等表征手段对合成催化剂的形貌和结构进行了表征。结果表明：CuO@HHSS催化剂依然保持HHSS的层次纳米中空结构;CuO颗粒高度分散在HHSS表面,而且复合催化剂具有较高的比表面积（488.9 m²/g）。以对硝基苯酚（4-NP）的催化还原反应作为反应模型,考察了CuO和CuO@HHSS催化剂对4-NP还原的催化性能。结果表明：在不同对硝基苯酚浓度下CuO@HHSS展现出优异的催化性能,在200 s内催化硼氢化钠（NaBH₄）将4-NP转化为对氨基苯酚（4-AP）。     

Microstructure and Mechanical Properties of Mullite–Silicon Carbide Composites

Mullite-SiC-whisker composites were prepared by powder processing using two commercial SiC whiskers. These composites were prepared by sintering rather than hot-pressing. A mulliteSlC-powder composite and a base line mallite material were also prepared for comparison with the two whisker composite materials. Fracture toughness measurements showed significant enhancement in only one of the whisker composite materials. The microstructure of the four materials was examined by scanning electron microscopy and transmission electron microscopy to assist in the explanation of the mechanical behavior of these composites. The examinations suggested that most of the toughening results from second-phase particles, with only limited toughening from effects associated with whiskers per se. In one case, higher toughness was partially associated with the formation of sialon phase by reaction with the whiskers and the furnace environment.     

碳纤维复合吸波涂层材料的性能影响研究

以水性聚氨酯为基,碳纤维为填料,制备了碳纤维复合吸波涂层材料。采用扫描电镜、差示扫描量热仪、傅里叶红外光谱仪、X射线衍射仪和矢量网络分析仪对碳纤维复合吸波涂层材料的结构与性能进行了测试和表征。实验结果表明:碳纤维复合吸波涂层材料为碳纤维和水性聚氨酯的物理结合,随着碳纤维含量的增加和厚度的增大,碳纤维复合吸波涂层材料的反射率峰值均向低频移动,当碳纤维含量为0.8%,涂层厚度为1.2 mm时,碳纤维复合吸波涂层的反射率峰值达到-6.01 dB,小于-5 dB的带宽为4.2 GHz,涂层面密度为1.02kg/m~2。     

Synthesis of citric acid modified β-cyclodextrin/activated carbon hybrid composite and their adsorption properties toward methylene blue

In this article, citric acid modified β-cyclodextrin/activated carbon hybrid (CA-β-CD/AC) composites were synthesized by crosslinking reaction, and their adsorption properties for methylene blue were studied. The scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and Brunauer–Emmett–Teller (BET) method were used to characterize the structure and the morphology of composite materials. It was investigated that the effect of experiment parameters on the adsorption performance including weight fraction of AC in the composite, the adsorbent dose, the initial concentration of MB, the solution pH value, contact time, and temperature. The maximum adsorption capacity calculated by the Langmuir isotherm is 862.07 mg g⁻¹. Kinetic studies show that the adsorption process follows the pseudo-first-order and pseud-second-order reaction models. Thermodynamic analysis indicated that the adsorption behavior was an exothermic reaction. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48315.