聚吡咯/海泡石一维纳米复合材料的制备及表征

以三氯化铁（FeCl3）为氧化剂,十二烷基磺酸钠（SDS）为掺杂剂,通过原位聚合的方法制备了聚吡咯/海泡石（PPy/SEP）纳米复合材料。研究了吡咯（Py）用量、聚合时间、氧化剂用量以及掺杂剂用量对复合材料电导率的影响,确定了制备导电复合材料的工艺条件。结果表明,在Py用量（以SEP质量计）为25 %,聚合温度为0 ℃,聚合时间为12 h,FeCl3/Py摩尔比为2.3/1,SDS/Py摩尔比为1/5的条件下制备的PPy/SEP复合材料电导率为2.15 S/cm。采用透射电镜、红外光谱、X射线衍射及热分析表征纳米复合材料的形貌与结构。结果表明,制备的PPy/SEP纳米复合材料为具有核壳结构的一维纳米复合材料,且PPy以非晶态的形式存在于SEP表面。     

PPy/Ni/NanoG复合材料的制备及导电性能研究

以聚吡咯（PPy）为基体,FeCl3作为氧化剂,十二烷基苯磺酸钠（DBSNa）作为掺杂剂,表面镀有金属镍(Ni)膜的纳米石墨微片（NanoG）作为二维层状纳米填料,通过原位聚合法制备了PPy/Ni/NanoG导电复合材料,并对其结构和导电性能进行了表征。结果表明,PPy与Ni/NanoG的相容性较好,PPy聚合物均匀地包覆在Ni/NanoG片层表面和边缘;Ni/NanoG的二维受限空间的阻隔作用能够有效抑制PPy分子链的卷曲和交联,使PPy分子链共轭程度提高,π电子的离域性增加;循环伏安测试表明复合材料的峰面积大,峰电流高,导电能力强;复合材料的导电性能随Ni/NanoG含量的增加由8.2 S/cm提高到103.6 S/cm,Ni/NanoG的阈值为2 %（质量分数,下同）。     

功能化碳纳米管/SMANa/聚醚砜导电分离膜的制备及性能

为改善聚醚砜(PES)导电分离膜的相容性和分离性能,将碱处理的苯乙烯-马来酸酐共聚物(SMANa)和功能化碳纳米管按照不同质量比与PES共混,使用非溶剂诱导相分离法成功制备功能化碳纳米管/SMANa/聚醚砜导电分离膜,对分离膜的结构、形貌和分离性能进行测试。结果表明：通过碱处理苯乙烯-马来酸酐共聚物,成功制备具有良好分散性的SMANa。当功能化碳纳米管添加量为6 g时,导电分离膜的电阻率达到2.929 97×10⁴Ω·cm,纯水渗透通量达到1 188.1 L/(m²·h),而对牛血清蛋白(BSA)的截留率为91.46%。在通入30 V电压后,导电分离膜对刚果红、甲基蓝染料渗透通量分别达到584 L/(m²·h)和480 L/(m²·h),截留率均达到99.99%。     

PLA/PPy复合材料的制备及表征

以吡咯(Py)为原料,通过原位聚合法合成聚吡咯(PPy)导电粒子,通过PPy粒子对聚乳酸(PLA)进行改性,制备PLA基导电复合材料,并对其形貌、力学性能及导电性能进行测试。结果表明:PPy可以与PLA基体呈现一种紧密结合的状态;PLA/PPy(5%)导电复合材料综合性能最佳,其拉伸强度为51.2 MPa、断裂伸长率为163.5%、电导率为4.12×10~(-5) S/cm。     

导电复合水凝胶的制备及性能测试

本文首先通过化学交联法制备聚乙二醇二丙烯酸酯-聚丙烯酰胺（PEGDA-PAAm）水凝胶修饰层，而后运用界面聚合法使导电聚合物聚吡咯（PPy）于水凝胶中聚合，则得到性能良好的导电水凝胶。选用316L不锈钢片为负载导电水凝胶的基底，制备掺杂药物地塞米松的水凝胶，通过电化学CV法刺激控制药物释放，实验结果表明，我们到了性能良好的药物释放体系。     

基于细菌纤维素的导电功能复合材料的制备及用于导电纸

以具有三维纳米纤维网络结构的细菌纤维素（BNC）为支撑基底,碳纳米管（CNT）或聚吡咯（PPy）为填充导电材料,通过原位生物培养复合制备导电功能复合材料,并将其应用于导电纸。采用了静态浅瓶培养、动态水平转鼓培养,以及氧化聚合法制备了多种BNC基导电功能复合材料,并对各导电复合膜的产量、宏观及微观（SEM）形貌、力学性能、结晶度、比表面积、导电性能等进行表征,探究最优的制备方式及反应条件,制备出性能优异的BNC基导电纸。结果表明,水平动态转鼓的发酵方式使得CNT的分布更均匀,动态制备的D-BNC/CNT复合膜的电导率随着CNT的负载量增加而增加,质量浓度为1%(wt)的D-BNC/CNT复合膜的电导率（0.94 S/cm）约为静态制备的S-BNC/CNT(0.015 S/cm)的62倍。氧化聚合法制备的D-BNC/PPy导电复合膜,在浓度为0.4%(wt)时力学性能（杨氏模量为3.65 MPa）与导电性能（电导率为0.14 S/cm）最优。D-BNC/1%(wt)CNT/0.4%(wt)PPy导电纸与市售的导电纸相比,导电性能具有明显的优势（二极管的光亮强度更大）,导电率达到2.87 S...     

聚吡咯/有机蒙脱土纳米复合材料的制备及其导电性

以三氯化铁(FeCl3)为氧化剂,对甲苯磺酸钠(TSANa)为掺杂剂,使进入经有机插层剂改性的有机蒙脱土(OMMT)层间的吡咯(Py)发生氧化聚合反应,制备了具有良好导电性的聚吡咯/有机蒙脱土(PPy/OMMT)纳米复合材料。结果表明,采用插层剂为十八烷基三甲基氯化铵(OTAC)改性的有机蒙脱土OMMT-O,FeCl3与Py的摩尔比为2 14,Py与OMMT-O的质量比为0 24,TSANa的浓度为0 023g·ml-1,在20℃反应6h,得到的PPy/OMMT-O纳米复合材料的电导率达到3 07S·cm-1。XRD测试表明,在形成复合材料过程中PPy已经插层进入到蒙脱土的片层中。     

界面氧化聚合法聚吡咯/硫化镉合成及性能

拟采用界面氧化聚合法制备聚吡咯膜,通过实验发现反应的最佳溶剂为三氯甲烷,最佳的氧化剂为过硫酸铵。当聚吡咯于过硫酸铵反应浓度均为0.15 mol/L左右时可以生成表面平整、厚度适中、力学性能较好的聚吡咯膜。通过将上述方法制备的聚吡咯膜先浸泡在醋酸镉溶液中吸附Cd~(2+),最后与硫代乙酰胺处理得到PPy/CdS复合材料。本实验采用了探针式表面轮廓仪分析、扫描电镜(SEM)、傅立叶红外光谱(FTIR)、X-射线衍射(XRD)、Z-扫描测试法、热重(TG)分析等对产物进行表征。结果表明,聚吡咯/硫化镉纳米复合材料上纳米粒子的分布状况及粒子大小与掺比浓度有关,浓度越低分布越密、粒子直径越小,当聚吡咯、硫化镉的掺杂比达到1:0.001时粒子直径可达20 nm左右。此外,复合了硫化镉纳米粒子后聚吡咯的热稳定性提高了33.3%。由Z-扫描结果显示PPy/CdS具有很强的三阶非线性特性。     

聚(吡咯/二苯胺磺酸)/石墨烯复合材料的制备及其抗静电性能研究

采用化学氧化聚合法,以石墨烯（RGO）为掺杂剂,吡咯（Py）和二苯胺磺酸（SD）共聚制备了导电复合材料。通过正交实验和分散性实验确定了最佳合成条件为：以FeCl3･6H2O为氧化剂,氧化剂与单体的摩尔比为1:1,Py与SD的摩尔比为7:3（总量为0.01 mol）,RGO添加量为0.05 g;在此条件下制备的复合材料电导率为12.05 S/cm,且具有良好的水分散性。用傅里叶变换红外（FTIR）光谱和X射线衍射（XRD）对其结构进行了表征,并使用热重分析仪（TGA）对复合材料的热稳定性进行了测试。结果表明,SD结构单元成功嵌入聚吡咯（PPy）的分子链中,RGO的掺杂使复合材料电导率和热稳定性都有了明显提升。将复合材料作为导电填料加入到水性聚氨酯中,考察了涂层的抗静电性能和机械性能,在添加量为4%时,涂层的综合性能较好,涂层表面电阻率可达8.65×107 Ω。     

PMIA/PDAPs复合超滤膜的制备与性能研究

以聚间苯二甲酰间苯二胺(PMIA)为制膜原料,以氧化自聚合法制备的聚多巴胺纳米粒子(PDAPs)作为改性剂添加到PMIA铸膜液中,通过相分离法制备PMIA/PDAPs复合超滤膜,研究了PDAPs含量对复合膜的形貌、结构及性能的影响。结果表明:PDAPs粒径集中分布在380～410 nm,当PDAPs质量分数小于等于0.2%时,PDAPs在PMIA基体中的分散性较好,并且在清洗后依然保留在膜体中;随着PDAPs含量的增加,复合膜的水接触角先下降后升高,水通量先升高后下降,牛血清蛋白(BSA)截留率下降,可逆通量恢复率则不断提高;与纯PMIA膜相比,当PDAPs质量分数为0.2%时,复合膜的水接触角下降了11%,水通量由原来的337.4 L/(m~2·h)提高到410.4 L/(m~2·h),对BSA蛋白质分子的截留率由87%降低至83%,可逆通量恢复率由72.9%提高到84.7%,复合膜表现出良好的亲水性和抗污性能。     

Compact Swelling in Bi1.4Pb0.6Sr2Ca2Cu3.6Oy During the Formation of High-Tc Superconducting Phase

Compact swelling in Pb-doped Bi-Sr-Ca-Cu-O superconductor has been studied by observing the effects of the size of calcined powders, volatilization of materials, and sintering of high- T _c (2223) powders. The bulk density increases at the early stage of sintering, for about 20 h, and then decreases. Densification occurs when the low- T _c (2212) phase and a liquid phase exist, whereas dedensification occurs with the formation of the 2223 phase regardless of the presence of the liquid. Gas evolution from specimens does not appear to be responsible for compact swelling. Compact swelling is explained by anisotropic growth of thin, platelike 2223 grains in random orientation. When 2223 grains grow in a preferred direction, compact swelling is suppressed.     

Synthetic routes to nanoscale BxCyNz architectures

B_xC_yN_z nanoscale materials, hybrids of h-BN and graphite, have been recently synthesised using various techniques. Here, we present the latest advances in the synthesis and characterisation of B-C-N nanotubes and nanofibres. In particular, we focus on layered BC₂N, BN, BC and CN_x systems, reviewing their production methods as well as their structural and electronic properties. These materials may find important applications in the fabrication of nanotransistors, robust nanocomposites, conducting polymers, storage components and field emission sources.     

Microwave Dielectric Properties of CaTiO3-CaAl1/2Nb1/2O3 Ceramics Doped with Li3NbO4

The microwave dielectric properties of CaTi_{1− x} (Al_1/2Nb_1/2) _x O₃ solid solutions (0.3 ≤ x ≤ 0.7) have been investigated. The sintered samples had perovskite structures similar to CaTiO₃. The substitution of Ti⁴⁺ by Al³⁺/Nb⁵⁺ improved the quality factor Q of the sintered specimens. A small addition of Li₃NbO₄ (about 1 wt%) was found to be very effective for lowering sintering temperature of ceramics from 1450–1500° to 1300°C. The composition with x = 0.5 sintered at 1300°C for 5 h revealed excellent dielectric properties, namely, a dielectric constant (ɛ_r) of 48, a Q × f value of 32 100 GHz, and a temperature coefficient of the resonant frequency (τ_f) of −2 ppm/K. Li₃NbO₄ as a sintering additive had no harmful influence on τ_f of ceramics.     

Preparation and properties of poly(Nε,Nε-dicarboxymethyl-l-lysine)

A new ampholytic homopolypeptide, $\text{poly}\text{(N}{}^{\mathrm{\epsilon }}\text{,N}{}^{\mathrm{\epsilon }}\text{-}\text{dicarboxy-methyl-}\text{l}\text{-lysine}\text{)}$, which has one tertiary amino and two carboxyl groups in the side chain has been derived from a hydrochloride salt of poly(L-lysine). The polymer in aqueous solution seems to be in the coil form with locally extended structure (LES) at neutral pH. In both the acidic and alkaline regions, the molar ellipticity of the polymer changes as a result of change in net charge on the side chain. The conformational changes may be from the coil with LES to other coiled forms. 5–7 M NaClO₄ and 80% aqueous methanol induce the α-helix in the polymer at neutral pH. Divalent cations, Cu²⁺ and Ca²⁺, do not induce any remarkably ordered structures such as α-helix or β-structure in the polymer in aqueous solution at any pH. Ultraviolet absorption studies show an absorption peak of the polymer-Cu²⁺ complex near 240 nm. Dependence of the peak intensity on pH at various q values ($\text{q =}\text{[}\text{Cu}{}^{\mathrm{2+}}\text{]}\text{[}\text{residue}\text{]}$) indicates the two steps of the complex formation. At q less than 0.64, the formation is described only with the first step. An average coordination number for Cu²⁺ at the first step was calculated to be about 2 by the method of Mandel and Leyte. The association constant of Cu²⁺ with the residue at the step was determined from the absorption data to be far smaller than that for the Cu²⁺-EDTA complex. The second step of the formation occurs in the case of large q but the absorption data for the second step cannot be obtained exactly due to precipitation.     

Structure Evolution from Pb(Mg1/3Nb2/3)O3 to La(Mg2/3Nb1/3)O3

The crystal structure of lanthanum-modified lead magnesium niobates having composition (Pb_{1− x} La _x ) (Mg_{(1+ x )/3}-Nb_{(2− x )/3})O₃ with X = 0 to 1 was investigated by X-ray powder diffraction. It was found that the fundamental reflections from perovskite structure remain in the whole range of composition. The superlattice reflections from the A(B'_1/2-B"_1/2)O₃ ordered structure are also well preserved for La content greater than 50 at.%; however, a series of extra peaks of mixing indices appears, with intensities gradually enhanced with the increase of La content. For the complete substitution of Pb by La, a splitting of some reflections can be observed in the diffraction pattern. The results indicate that the crystal structure evolves continuously with the La content, from disordered cubic perovskite of space group Pm 3 m for X = 0, to ordered cubic perovskite of space group Fm 3 m for X = 0.5, distorted cubic perovskite of space group Pa 3 for 0.5 < X < 0.9, and finally to a rhombohedral perovskite, possibly belonging to the space group R 3 , for X ≥ 0.9. In the evolution of structure, a linear reduction of the lattice constant of the perovskite cell from 4.048 to 3.964 Å was observed.     

Characteristic Spherulitic Microstructure in Partial-Melt-Processed YBa2Cu3Ox/HfO2

The microstructure of partial-melt-processed YBa₂Cu₃O _x /HfO₂ has been studied by transmission electron microscopy. A characteristic spherulitic microstructure is formed in the system. A model for the growth mechanism has been proposed. The critical heterogeneous nucleation of the YBa₂Cu₃O _x phase appears to occur from the melt in an epitaxially controlled manner on CuO particles. Subsequent growth of YBa₂Cu₃O _x platelets from the nucleus region is repeatedly interrupted by the nucleation of hafnium-rich phases in the liquid at the solid/liquid interface in a manner that again appears to be epitaxially controlled and that promotes the splay of the c orientation of the YBaCuO grain.