多功能性聚苯胺/聚合物纳米复合材料的制备及应用

基于国内外最新研究文献及本课题组的研究,综述了多功能性聚苯胺/聚合物纳米复合材料的制备方法、性能及应用前景。聚苯胺/聚合物纳米复合材料可以由机械共混法、涂布法和原位聚合法,如分散聚合法、模板诱导聚合法及电化学聚合法制备得到。聚苯胺/聚合物纳米复合材料在透明导电塑料薄膜、防静电涂料、导电纤维、电致发光器件、电磁屏蔽材料等领域有着广阔的应用前景。     

石墨烯制备、改性及其聚合物复合材料研究进展

石墨烯是由海姆和诺沃肖洛夫2004年首先制备的,是世界上最薄的二维材料,其厚度仅为0.35nm。石墨烯的优异性能及应用前景使其成为国内外的研究热点。本文综述了近年来石墨烯制备、改性及其聚合物复合材料研究进展。展望石墨烯填料在塑料领域的应用前景。     

纳米导电聚合物复合材料的制备及应用

纳米导电聚合物是一种新型功能高分子材料,近年来,其复合材料的研究和应用越来越受到重视。本文综述了纳米导电聚合物复合材料的制备方法及在能源、电磁屏蔽、电致发光等领域应用研究的最新进展,并对其今后的发展趋势进行了展望。     

新型石蜡基复合材料的研究进展

石蜡基复合材料具有不同的组成和结构,包括氧化物/石蜡、单质/石蜡、聚合物/石蜡等二元复合材料以及石蜡基三元复合材料。它们具有优异的物理和化学性质,在众多领域里显示出广阔的应用前景,如润滑与摩擦学、储能材料和传感器等领域。制备具有新颖组成和结构的石蜡基复合材料及其应用研究已经成为复合材料领域的研究前沿和热点之一。综述了新型石蜡基复合材料的组成、制备以及应用的研究进展,探讨了该研究领域亟待解决的问题以及今后可能的发展前景。     

聚合物/层状硅酸盐纳米复合材料制备研究进展

近年来,聚合物基有机/无机纳米复合材料作为材料科学领域中的一枝新秀,已引起人们的广泛关注,这类材料具有有机和无机材料的特点,并通过两者之间的耦合产生出许多优异的性质,有着广阔的应用前景.聚合物与蒙脱土插层是制备高性能聚合物/层状硅酸盐纳米复合材料的一种新方法,也是当前材料科学领域的研究热点.本文从材料结构及性能、制备方...     

纳米碳纤维及其在聚合物中的应用

纳米碳纤维/聚合物复合材料是近年来的热点研究领域.本文简要介绍了纳米碳纤维的几种制备方法及纳米碳纤维/聚合物复合材料的应用前景,讨论了纳米碳纤维在聚合物中的分散、取向和界面相互作用对复合材料性能的影响,介绍了加入纳米碳纤维赋予聚合物光电性能和目前尚待研究的一些问题.     

聚合物/粘土纳米复合材料的研究进展

聚合物 /粘土纳米复合材料因其优异性能是目前材料科学研究的热点之一。简述了聚合物 /粘土纳米复合材料的特点 ,介绍了几类聚合物 /粘土纳米复合材料的制备方法 ,展望了聚合物 /粘土纳米复合材料的应用前景     

单聚合物复合材料制备研究进展

简要介绍了生物降解高分子材料及其分类,综述了聚乙烯、聚丙烯、聚酰胺、聚酯类等不同单聚合物复合材料的制备研究进展和制备过程中存在的问题。指出了高性能单聚合物复合材料制备方法研究的核心问题和方向。     

超支化聚合物的研究进展

综述了近年来超支化聚合物的研究状况和技术进展,重点讨论了超支化聚合物的分子结构设计、合成及改性方法,及其在生物材料、光电材料、纳米复合材料、功能涂料等众多领域的应用。同时对超支化聚合物的发展趋势和应用前景进行了分析和展望。     

铝硅酸盐聚合物及其复合材料研究进展

铝硅酸盐聚合物及其复合材料具有低温制备、工艺简单、成本低、可沿用多数树脂基复合材料的制备工艺成型复杂形状构件、轻质、耐热、阻燃、耐腐蚀、对核废料及重金属离子固封效果好等优点,能够满足国家对节能降耗和CO2减排的需要,因此在传统建筑、冶金等领域具有广阔的应用前景;它还可通过掺杂改性赋予其导电、电磁屏蔽、吸波隐身等功能特性,且可通过高温陶瓷化处理获得力学和热学性能宽温域调控的榴石陶瓷及其复合材料,在航空航天用低成本耐热结构材料、防/隔热材料、吸波隐身材料等方面具有重要潜在应用。系统评述了国内外在铝硅酸盐聚合物及其复合材料方面的研究进展,包括铝硅酸盐聚合物的聚合机理和性能特点、为克服其脆性缺点而发展的各种类型复合材料,以及最近铝硅酸盐聚合物在转化制备先进陶瓷、核废料固封、新型建筑材料等领域的应用研究进展,并且指出了其发展方向。     

Full characterization for material constants of a promising KNN-based lead-free piezoelectric ceramic

Potassium-sodium niobate (K_1-xNa_xNbO₃, referred to as KNN) solid solutions, which are an important type of lead-free piezoelectric materials possessing environmentally friendly features, good piezoelectric response and high Curie temperature, have attracted considerable attention in replacing lead-based ceramics. In order to promote the application of KNN-based ceramics in piezoelectric devices, we characterized a complete set of material constants of a high performance KNN-based ceramic, that is 0.965(K_0.48Na_0.52) (Nb_0.96Sb_0.04)O₃-0.035Bi_0.5Na_0.5Zr_0.15Hf_0.75O₃ (KNNS-BNZH), whose Curie temperature is 235 °C, piezoelectric coefficient d₃₃ is 380 pC/N and electromechanical coupling factor k₃₃ is 70%. These results will benefit the design of piezoelectric transducers and actuators using lead-free piezoelectric ceramics.     

Mechanical,dielectric, and thermal properties of fluorosilicone rubber composites filled with silica/multiwall carbon nanotube hybrid fillers

In this work, hybrid fillers consist of modified silica (SiO₂) and multiwalled carbon nanotube (MWCNT) were used to improve the mechanical, dielectric, and thermal properties of fluorosilicone (FSR) composites via a direct mechanical mixing method. With the increase of CNT loading in SiO₂/CNT hybrid loading ratio, the tensile properties, dielectric constant, electrical conductivity, and thermal properties all increase without a sharp sacrifice of flexibility. The dielectric constant of FSR-S15/C5 achieved 7,370 @1 kHz, which is about four orders of the FSR-S20, and the dielectric loss remains as low as 0.676 @1 kHz. Therefore, the linkage of SiO₂ and FSR chains not only enhances the interfacial interaction between the fillers and FSR matrix but also decreases the agglomeration of the fillers in matrix. What is more, modified SiO₂ and CNT were designed as the effective hybrid filler to improve the performance of the polymeric matrix through synergic effect.     

Investigation of dielectric and piezoelectric properties in aliovalent Eu3+-modified Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics

Rare earth (Eu³⁺)-modified Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) polycrystalline ferroelectric ceramics were fabricated by high-temperature solid-state sintering, the phase structure, dielectric and piezoelectric properties were investigated. Eu³⁺ addition was found to significantly improve dielectric and piezoelectric properties of PMN-PT, where the optimized properties were achieved for the composition of 2.5 mol%Eu: 0.72PMN-0.28PT, with the piezoelectric d₃₃ = 1420 pC/N, dielectric ε_r = 12 200 and electromechanical k₃₃ = 0.78, respectively. All these results indicate that the Eu³⁺-doped PMN-PT ceramics are promising candidates for high-performance room-temperature piezoelectric devices.     

High magnetic and ferroelectric properties of BZT-LSM multiferroic composites at room temperature

In this research, the effects of La_0.7Sr_0.3MnO₃ additive on the phase evolution, microstructure, dielectric, ferroelectric and magnetic properties of BaZr_0.07Ti_0.93O₃ ceramics were systematically investigated. The (BaZr_0.07Ti_0.93O₃)/x(La_0.7Sr_0.3MnO₃) or BZT/xLSM (where x?=?0, 5, 10 and 20?mol%) ceramics were prepared via a solid state reaction method. A pure perovskite phase is observed for the samples of x?≤?10?mol%. The M-H hysteresis loops also show an improvement in the magnetic behavior for higher LSM content samples as well as the modified ferroelectric properties. However, the 5?mol% sample exhibited the optimum ferroelectric and ferromagnetic properties with remnant magnetization (M_r) and remanent polarization (P_r) of 2.38?emu/g and 10.5?µC/cm², respectively. The dielectric-temperature curves show that the two phase-transition temperatures as observed for the unmodified BZT ceramic merges into a single phase-transition temperature for the 5?mol% sample and then become flat curves for the 10?mol% sample. In addition, the mechanical properties i.e. Knoop hardness and Young's modulus values increase with increasing LSM content, where Knoop hardness and Young's modulus values for the 20?mol% sample are increased by ~ 45% and ~ 104%, respectively, as compared to the unmodified sample.     

A methacrylate monomer bearing nitro,aryl, and hydroxyl side groups: Homopolymerization,characterization, dielectric,and thermal degradation behaviors

2‐Hydroxy‐3‐(4‐nitrophenoxy)propyl methacrylate (HNPPMA) monomer was synthesized. The poly(HNPPMA) was prepared by free radical polymerization (FRP) method. The characterization of poly(HNPPMA) was carried out using FT‐IR, NMR, differential scanning calorimetry, and GPC techniques. The thermal stability and degradation behavior of this polymer have been studied by using thermogravimetry (TG), GC‐MS, NMR, and FT‐IR. The results were in comparison to poly[2‐hydroxy‐3‐(1‐naphtyloxy)propyl methacrylate] sample with α‐naphtyloxy side group prepared by the same method in the our previous study. The effect of thermal activation on non‐isothermal decomposition kinetics of poly(HNPPMA) was investigated using thermogravimetric analysis according to Flynn‐Wall‐Ozawa method. The dielectric measurements of poly(HNPPMA) and doped with europium(III)chloride (EuCI₃) were investigated by impedance analyzer technique in range of 10–4000 Hz frequency by depending on the alternating current conductivities. The mode of thermal degradation including formation of the main products of poly(HNPPMA) degraded from ambient temperature to 500 °C was identified. S°, the cold ring fraction (CRF) was collected from room temperature to 500 °C. The structure of the degradation products has also been studied depending on the GC‐MS analysis. The thermal degradation mechanism for poly(HNPPMA) with radical degradation processes thought to dominate at high temperature was proposed based on GC/MS, NMR, FT‐IR, and taking into account the new products and differences in stability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43925.     

PVDF piezoelectric voltage coefficient in situ measurements as a function of applied stress

Direct piezoelectric g₃₁ voltage coefficient was measured in situ as a function of applied tensile stress for films of polyvinylidene fluoride (PVDF). Measurements were performed under quasi‐static conditions with applied strain rates of 0.5–1.5 mm/min for strains up to 12%. Open‐circuit voltage was measured with a contact‐less electrostatic voltmeter. Obtained results show a strong dependence of the g₃₁ coefficient of mono‐oriented PVDF films on the applied stress, with a maximum value of the coefficient in the transition region between elastic and plastic deformation zones. The effect of sample geometry on the apparent g₃₁ coefficient is shown and discussed. The anisotropy of the piezoelectric effect is studied by means of g₃₁ and g₃₂ measurements. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43248.     

Metallopolymers based on a polyazomethine ligand containing rigid oxadiazole and flexible tetramethyldisiloxane units

Soluble, easily processable polymer–metal complexes with improved optical and dielectric properties for optoelectronic functional materials were obtained. For this, a new polyazomethine (PAZ2) was prepared by the reaction of a siloxane dialdehyde and bis(formyl‐p‐phenoxymethyl) tetramethyldisiloxane with 2,5‐bis(p‐aminophenyl)‐1,3,4‐oxadiazole, and it was used as a ligand for Cu(II), Co(II), and Zn(II) ions on the basis of the presence of the electron‐donor nitrogen atoms from the azomethine group and oxadiazole ring. The structure of the PAZ2 was determined by spectral [Fourier transform infrared (FTIR) and ¹H‐NMR spectroscopy] techniques. The metal complexation was proven by FTIR spectroscopy, and the silicon‐to‐metal ratios in the complexes were established by energy‐dispersive X‐ray fluorescence. The new materials were characterized by gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. The optical properties of PAZ2 and the derived metal complexes were studied by ultraviolet–visible and fluorescence spectroscopies. PAZ2 shows fluorescence emission, and it was significantly enhanced by metal complexation. The emission was enhanced by protonation; this behavior is useful, especially for sensors. The electrical properties were investigated by dielectric spectroscopy at various frequencies and temperatures, and this emphasized the existence of dipolar relaxations. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41631.     

The effect of the Zn/Sn ratio on the formation of single phase kesterite Cu2ZnSnS4 solar cell material

The effect of the Zn/Sn ratio in the solution on the properties of Cu₂ZnSnS₄ films prepared by sol-gel method has been investigated. As the Zn/Sn ratio in the solution increases to a certain value, a pure single phase kesterite CZTS is obtained and confirmed by XRD, XPS and Raman. Through controlling the Zn/Sn ratio in the solution, secondary phases such as SnO₂ can be avoided and an optimal condition for single phase kesterite CZTS can be achieved. Surface SEM images of the CZTS films are investigated and the optical band gap of the optimized CZTS film is found to be 1.23 eV.     

Photoluminescence and unique magnetoluminescence of transparent (Tb1-xYx)3Al5O12 ceramics

Luminescent transparent ceramics (Tb_1-xY_x)₃Al₅O₁₂ (x = 0, 0.2, 0.5, 0.8) are successfully prepared by a solid-state method with additional hot isostatic pressing (HIP) treatment, and the structure and properties are investigated by XRD, SEM, PL, UV–Vis spectrophotometry and ellipsometry. The Y-containing samples are shown to be solid solution phases between TAG and YAG. The PL intensity is 14 times stronger with the incorporation of 80 mol.% Y, and the ⁵D₄→⁷F₅ emission lifetime of Tb³⁺ is prolonged from 0.357 to 3.035 ms at room temperature. A unique magnetoluminescence emerges upon the incorporation of Y, showing an interesting emission decrease to 55% as the Y content reaches 80 mol.%. Remarkably, this magnetoluminesence can occur at room temperature without an intense magnetic field. Based on our work, transparent (Tb_1-xY_x)₃Al₅O₁₂ ceramics exhibit the potential for applications in green emitters, optical instruments and photoelectric devices. In particular, the magnetoluminescence provides a simple, noncontact and nondestructive route for probing magnetic fields.     

γ Irradiation effects on optical,thermal, and mechanical properties of polysulfone/MWCNT nanocomposites in argon atmosphere

Polymer‐based composites find use in many nuclear and space application for their ease of fabrication, tailor made properties and light weight. Certain polymers like PTFE, unfilled polyesters and polyamides are prone to degradation in presence of high energy radiation while polymers like epoxies, polyimides, and poly‐ether ether ketone have good stability to ionizing radiation. Incorporation of fillers like carbon nanotubes (CNTs) is likely to improve the radiation resistance of the polymers. In this work, polysulfone (PSU)‐based nanocomposites were fabricated using multiwalled carbon nanotube (MWCNT) by solution mixing process. The morphology of the PSU/ MWCNT nanocomposites films were studied using Field Emission Scanning Electron Microscopy (FESEM). The prepared films were subjected to γ radiation in an argon environment (to avoid the effect of air/oxygen). Different techniques were used to understand the radiation‐induced changes. Gel Permeation Chromatography (GPC) traces of neat PSU before and after exposure to radiation shows a decrease in molecular weight. Infrared spectroscopy shows changes in chemical structure. Differential Scanning Calorimetry (DSC) thermograms reveal dose‐related changes. For neat PSU, a decrease in T_g was observed with increase in dose. For PSU/ MWCNT nanocomposites, the increase in MWCNT content and dose (up to 1.5 MGy) increased the T_g. Thermo Gravimetric Analysis (TGA) showed a marginal decrease in thermal stability for pristine PSU as well as PSU/MWCNT nanocomposites with irradiation. Tensile strength increased with increasing MWCNT content but decreased with dose. Elongation at break decreased with MWCNT content as well as radiation dose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42017.