纳米SiO2-Al2O3聚酰亚胺杂化薄膜的制备及表征

采用溶胶凝胶法制备了二氧化硅及三氧化二铝溶胶,将其掺入聚酰胺酸基体中,得到SiO2-Al2O3聚酰亚胺杂化薄膜,对膜的结构性能进行了研究和表征.结果表明,薄膜材料中SiO2和Al2O3粒子分散均匀,与有机相存在键合,材料热分解温度有所提高.     

聚酰亚胺/二氧化硅杂化薄膜的制备与性能研究

首先将3-氨丙基三乙氧基硅烷接枝到纳米二氧化硅表面,制得表面含有氨基的改性纳米二氧化硅粒子(A—SiO2)。再将A—SiO2按不同比例与酐封端的聚酰胺酸进行反应,最后经热酰胺化过程,得到一系列聚酰亚胺/二氧化硅杂化膜。采用红外光谱(FT-IR)、X-射线衍射(XRD)、紫外光谱(UV-vis)、热重分析(TGA)、动态机械热分析仪和扫描电镜(SEM)对合成的聚酰亚胺及其二氧化硅杂化薄膜进行了表征。UV-vis光谱表明,通过向聚酰亚胺薄膜中添加A—SiO2可以改变聚酰亚胺薄膜的透光性。TGA测试结果表明,随着A—SiO2含量的增加,聚酰亚胺/二氧化硅杂化薄膜的热稳定性有所提高。由机械性能测试可知,当A—SiO2掺杂量小于1.5%时,聚酰亚胺/二氧化硅杂化膜的机械性能优于纯聚酰亚胺的机械性能,当A—SiO2的掺杂量大于2.0%时,聚酰亚胺/二氧化硅杂化膜的机械性能比纯聚酰亚胺的机械性能差。SEM分析可知当A—SiO2粒子含量小于1.5%时,其在聚酰亚胺基体中分散均匀,当含量大于2.0%时,体系出现明显团聚现象。     

纳米Al203/PI三层复合薄膜的制备与表征

以3,3′,4,4′-二苯酮四甲酸二酐(BTDA)和4,4′-二氨基二苯醚(ODA)为缩聚单体,利用高压静电纺丝技术制备出纳米Al_2O_3/PAA(聚酰胺酸)复合薄膜.以均苯四甲酸二酐(PMDA)和4,4′-二氨基二苯醚(ODA)为原料制备出聚酰胺酸铺膜胶液,在电纺膜的两侧进行流延成膜,并热亚胺化处理.对复合薄膜进行化学组成、微观形貌、耐电晕性能、力学性能和热学性能测试分析.结果表明:复合薄膜的亚胺化较完全,纳米Al_2O_3均匀地分散在聚酰亚胺基体中,在纳米氧化铝掺杂量为6%时综合性能最佳,耐电晕老化时间为12.3 h,是未掺杂纳米氧化铝三层复合薄膜的3倍以上,拉伸强度达到最大值(174 MPa),同时断裂伸长率达到21%.纳米Al_2O_3的加入使得复合薄膜的热稳定性有所提高,起始热分解温度从578.7℃提高到591.3℃.     

超声分散法制备聚酰亚胺／碳纳米管复合材料

以3,3′4,4′-二苯甲酮四羧酸二酐(BTDA)及4, 4′-二氨基二苯基醚(ODA)为基本原料, 采用超声分散法,掺入碳纳米管,制备了聚酰亚胺/碳纳米管复合材料. 在不同超声时间、不同超声频率下对纳米粒子进行了分散研究,并对聚酰亚胺/碳纳米管复合材料结构表征,从力学性能,导电性能等方面进行了研究. 研究表明:超声频率325 Hz,超声时间90 min时,碳纳米管在聚酰亚胺膜中得到很好分散,聚酰亚胺/碳纳米管复合材料的力学性能和导电性能优于聚酰亚胺膜.     

透明耐高温聚酰亚胺薄膜的制备及形状记忆性能的研究

本研究以N,N′-(2,2′-双(三氟甲基)联苯-4,4′-二基)双(1,3-二氧代-1,3-二氢异苯并呋喃-5-甲酰胺)(TATFMB)和4,4′-二氨基-2,2′-双(三氟甲基)联苯(TFMB)为单体制备聚酰胺酸(PAA)溶液,加入八(氨基苯基三氧硅烷)(OAPS)作为交联剂,通过热亚胺化得到了透明聚酰亚胺薄膜.差示扫描量热法(DSC)、动态热机械分析(DMA)和热失重分析(TGA)测定表明,多面体聚硅氧烷(POSS)结构的引入提升了材料的耐热性与热稳定性,同时赋予材料形状记忆性能.相比于以往报道的形状记忆聚酰亚胺,TATFMB/TFMB/OAPS聚酰亚胺薄膜具有高的玻璃化转变温度(tg).该薄膜具有良好的透明性(400～800nm平均光透过率92%,500nm处透过率91%).热机械分析(TMA)测试的结果表明,二酐单体TATFMB的引入使得聚合物具有较低的热膨胀系数(CTE).所制备的透明耐高温聚酰亚胺薄膜拓展了聚酰亚胺材料在光电显示器件与高温形状记忆材料领域的应用.     

聚酰亚胺/纳米金复合材料的制备及其性能研究

以2,2'-双[4-(3,4-二羧基苯氧基)苯基]丙烷二酐(BPADA)、4,4'-联苯醚二酐(ODPA)和二氨基二苯醚(ODA)三者合成的共聚聚酰亚胺作为稳定剂,氯金酸为纳米金的前驱体,通过直接还原法制备综合性能优异的复合纳米材料.然后对复合材料结构、热性能、机械性能、光学性能进行表征.金纳米粒子在共聚聚酰亚胺基体中分散均匀.在金纳米粒子的负载量达到0.45%之前,复合膜的热稳定性和机械强度均随着纳米金负载量的增加升高,这是因为无机纳米粒子的引入提高复合薄膜的结晶度造成的.当纳米金的负载量超过0.45%时,由于金纳米粒子的团聚是的复合薄膜的热稳定性和机械性能下降.复合膜在可见光区的紫外透过率达到80%左右.     

聚酰亚胺／二氧化硅纳米杂化材料制备

通过溶胶－凝胶方法（sol-gel）,利用已水解的正硅酸乙酯（TEOS）与芳香族的聚酰胺酸（PAA）溶液混和,制备出了不同二氧化硅含量的杂化薄膜。在实验中,首次采用偶联剂来提高无机组分二氧化硅与有机组分聚酰胺酸的相容性,制备各种二氧化硅含量的有机－无机透明的杂化薄膜。扫描电镜分析结果表明,杂化膜的微观相结构与二氧化硅的含量、偶联剂的加入有关。     

聚酰亚胺纳米杂化材料的研究进展

纳米粒子在PI材料中分散性良好,聚酰亚胺(PI)中引入无机纳米粒子,可弥补PI的性能缺陷(如较高的热膨胀系数和较低的吸水性),非常适合对PI改性。本文阐述了PI纳米杂化材料的制备方法以及纳米杂化材料的特点及应用。     

聚酰亚胺/无机物纳米杂化材料的研究Ⅱ.聚酰亚胺(TDPA/ODA)-BaTiO_3纳米杂化物的合成与表征

由碳酸钡、钛酸丁酯和乳酸制得钛酸钡多晶相.WAXD和TEM 分析表明, 该钛酸钡具有典型的钙钛矿结构, 粒径为30～50 nm . 此钛酸钡纳米粉被成功地分散于聚酰胺酸中并制得聚酰亚胺(TDPA/ODA) 杂化材料. TEM 和AFM 表明低含量 (< 1% BaTiO3) 的杂化膜, 无机物是以< 50 nm的球状颗粒均匀分散于聚酰亚胺基体中, 高含量 (如30% ) 杂化膜是具有光滑表面的韧性薄膜. 后者介电常数与压电常数比纯聚酰亚胺提高了近一倍.     

聚酰亚胺/无机物纳米杂化材料的研究Ⅱ.聚酰亚胺(TDPA/ODA)-BaTiO3纳米杂化物的合成与表征

由碳酸钡、钛酸丁酯和乳酸制得钛酸钡多晶相.WAXD和TEM分析表明,该钛酸钡具有典型的钙钛矿结构,粒径为30～50 nm.此钛酸钡纳米粉被成功地分散于聚酰胺酸中并制得聚酰亚胺(TDPA/ODA)杂化材料.TEM和AFM表明低含量(＜1% BaTiO3)的杂化膜,无机物是以＜50 nm的球状颗粒均匀分散于聚酰亚胺基体中,高含量(如30%)杂化膜是具有光滑表面的韧性薄膜.后者介电常数与压电常数比纯聚酰亚胺提高了近一倍.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with