二阶非线性光学活性聚酰亚胺有机-无机杂化材料的合成与表征

通过溶胶-凝胶法制备了含二阶非线性光学发色团分散红19(DR₁₉)的硅氧烷染料与聚酰亚胺有机-无机杂化材料.利用红外光谱、紫外-可见光谱、SEM、DSC和TGA等手段对其进行了表征.杂化极化后的序参数高达0.48,并具有优良的极化取向稳定性,423K下处理300h后,序参数仍能保持初始值的90%.杂化薄膜有较好的表面平整性,其断面呈网络结构.杂化材料的玻璃化转变温度(T_g)为561K,比纯聚酰亚胺的T_g(543K)高18K,表现出优良的高温热稳定性,其5%热失重温度为691K,10%热失重温度为758K.     

高Tg可溶含偶氮三嗪染料基团的侧链型共聚聚酰亚胺的合成与表征

采用两步法合成了两个系列侧链含新型侧氮三嗪染料发色团的共聚聚酰亚胺ＯＰＩ（ｘ）和ＰＰＩ（ｘ）。用红外光谱,紫外－可见光谱ＤＳＣ和ＴＧＡ等手段对其进行表征,它们均溶于强极性非质子溶剂,如ＮＭＰ,ＤＭＡｃ,ＤＭＦ,ＤＭＳＯ和１,４－丁内酯等。其截止吸收波长小于５００ｎｍ,在大于５００ｎｍ,波长范围内基本透明,这些共聚物的特性粘数在０．２５－０．５０ｄＬ／范围内,它们都表现出较高的玻璃化转变温度（Ｔｇ）,以刚性相对较大的均苯四甲酸二酐（ＰＭＤＡ）为二酐单体的ＰＰＩ（ｘ）的Ｔｇ在５７３Ｋ左右;以二苯醚－３,３′,４,４′－四甲酸二酐（ＯＰＤＡ）为单体的ＯＰＩ（ｘ）的Ｔｇ在５３３－５４３Ｋ之间,具基本与染料发色团含量无关,所有的共聚聚酰亚胺都表现出优良的的高温稳定性,其５％热失重温度比相应聚合物Ｔｇ高１００Ｋ以上。     

侧链含偶氮苯发色团的聚酰亚胺薄膜的制备及其三阶非线性光学和光存储性能的研究

将4,4'-二氨基三苯甲烷(DTM)单体与均苯四甲酸酐(PMDA)进行缩聚反应,再与对-硝基苯基重氮氟硼酸盐进行重氮偶合反应,然后经酰亚胺化合成了侧链含偶氮苯发色团的聚酰亚胺非线性光学材料(NLOPI).通过红外光谱对产物进行了结构表征.对产物的紫外-可见吸收光谱研究发现,在330和490nm处出现侧链偶氮苯发色团的特征吸收.通过简并四波混频方法(DFWM)测定侧链含偶氮苯发色团的聚酰亚胺薄膜的三阶非线性极化率χ⁽³⁾=4.58×10^-18m²/W.在DFWM中,前向泵浦光I_f和探测光I_p是主要的写入光,而后向泵浦光I_b是主要的读出光.证实了光致偶氮分子的顺反异构能够导致光信息存储的特性.     

侧链含分散红类染料基团的聚(氨酯-酰亚胺)的合成与表征

采用两步法合成了4种侧链含偶氮染料发色团分散红-19的新型聚(氨酯-酰亚胺)(PUI):先合成含染料发色团的二异氰酸酯,再进一步和二酐单体缩合生成PUI.用红外光谱、紫外-可见光谱、DSC和TGA等手段对合成的PUI进行表征.所有PUI在～490nm处都有一强吸收峰.PUI可溶于强极性非质子溶剂,如NMP,DMAc,DMF,DMSO和1,4-丁内酯,有些甚至在常用的低沸点溶剂如THF中也可溶解.PUI的特性粘数在0.16～0.31dL/g范围内.其玻璃化转变温度(Tg)在171～211℃范围内,明显高于侧链型非线性光学聚氨酯(PU).以刚性相对较大的六氟异丙叉基二(3,4-邻苯二甲酸酐)(6FDA)和甲苯-2,4-二异氰酸酯(TDI)为单体的PUI具有比以二苯醚-3,3′,4,4′-四甲酸二酐(OPDA)和4,4′-二异氰酸酯二苯甲烷(MDI)为单体的PUI更高的T_g.PUI的TGA曲线上有两个明显的失重台阶,起始热分解温度大约在300℃左右.     

一种新型的交联极化聚合物的合成及性能研究

以成膜性能优异、主链上含有多个羟基的聚双酚A二缩水甘油醚-苯胺(BPAN)为骨架,将二阶非线性光学活性发色团分子以键合形式挂接到聚合物主链上,形成新型侧链型聚合物.此聚合物保留了原聚合物体系成膜性好和可进一步交联等优点.极化过程中以含有异氰酸酯基的同种发色团分子作为交联剂,得到发色团含量进一步提高的交联型极化聚合物.采用衰减全反射法(ATR)测得体系的电光系数(r₃₃)为6.7 pm/V(1315 nm).     

含叔丁基/异丁基二胺的可溶性透明聚酰亚胺的合成与性能

通过分子设计合成了异丁基桥联2-叔丁基苯胺的新型二胺单体4,4′-(2-异丁基)双(2-叔丁基苯胺), 并将其分别与4种商品化芳香族二酐经高温“一步法”缩聚制得了系列聚酰亚胺(PI)树脂. 采用多种测试手段研究PI的结构和性能, 结果表明, 该系列新型聚酰亚胺不但可溶于N-甲基吡咯烷酮及N,N-二甲基甲酰胺等高沸点溶剂, 而且在乙酸乙酯和三氯甲烷等低沸点溶剂中也具有良好的溶解性. 该系列PI保持了良好的热稳定性, 在N₂中5%热失重温度均在480 ℃以上, 玻璃化转变温度(T_g)介于307~356 ℃之间. 经溶液刮涂制得的PI薄膜具有良好的光学透明性, 在可见光区平均透过率可达82.3%~89.1%, 截止波长介于313~363 nm之间. 同时, 该系列PI薄膜还具有良好的机械性能和疏水性, 有望应用于光伏发电及柔性显示等领域.     

可交联的PMMA型和PS型高热稳定性二阶非线性光学材料的合成与表征

采用封管反应的方法,以较高产率(80%以上)合成了一系列含环氧基团的可交联PMMA型和PS型极化聚合物材料,该材料具有很好的成膜性.用DSC和T_gA等方法研究了聚合物固化前后的热性能,结果表明,由于聚合物在极化后期经热固化使引入的环氧基团开环交联,聚合物的玻璃化转变温度(T_g)较固化前明显提高30～50K.同时,固化后的聚合物具有较高的热分解温度(T_d>543K).对聚合物的二阶非线性光学性质的测试结果表明,在室温下放置100h后,聚合物的电光系数r₃₃值均保持在初始值的75%以上.这是由于环氧基团的开环使固化后的聚合物本身产生一定程度的交联,导致取向后的发色团被聚合物的交联网禁锢而不易弛豫,从而使这类PMMA型和PS型二阶非线性聚合物材料的热稳定性能得以提高.     

耐超高温双酮酐型聚酰亚胺的合成及性能

以4,4'-对苯二甲酰二邻苯二甲酸酐(TDPA)为芳二酐单体,对苯二胺(PPD)为芳二胺单体,经低温溶液缩聚制得成膜性能优良的高相对分子质量聚酰胺酸(PAA),再经过热亚胺化制备双酮酐型聚酰亚胺(PI)薄膜。 采用傅里叶变换红外光谱仪(FT-IR)、广角X射线衍射(WAXD)、差示扫描量热仪(DSC)、动态热机械分析仪(DMA)、热重分析仪(TGA)、紫外-可见分光光度计(UV-Vis)及力学性能等技术手段表征了聚酰亚胺膜的结构和性能,考察了不同亚胺化温度对合成的双酮酐型聚酰亚胺膜性能的影响。 结果表明,经程序升温至320 ℃能使PAA热亚胺化基本趋于完成。 PI薄膜为部分有序聚集态结构,玻璃化转变温度(T_g)为298 ℃,具有优异的热性能,热失重温度(T_5%)为523 ℃。 拉伸强度达到130 MPa,弹性模量为5.77 GPa。 PI薄膜紫外光透过截止波长为375 nm,在可见光区具有良好的透光性能及耐溶剂性能。     

基于金属配位作用制备高性能聚酰亚胺

通过分子结构设计合成了含金属配位交联网络的可溶性聚酰亚胺,由于Cu²⁺与聚酰亚胺侧链羧基之间的配位交联作用限制了聚酰亚胺分子链的运动,使材料的T_g得到显著提升.同时,由于Cu²⁺具有非球面对称的电子云结构,导致Cu²⁺在与有机配体配位时存在额外的晶体场稳定能（CFSE）以及较强JahnTeller效应（JTE）,使配位键能够在有机溶剂中稳定存在,极大地提高了薄膜的抗溶剂性能,制备的聚酰亚胺膜在DMF、DMAc等强极性溶剂中室温下浸泡48 h后质量残留率仍可高达80%.此外,在聚酰亚胺分子结构中引入金属离子配位作用使其力学性能明显提升,拉伸强度从93 MPa提高到128 MPa.研究结果为开发高性能可溶性聚酰亚胺材料提供新途径.     

新型含有多氰基受体单元的近红外敏化染料的合成及其光伏性能研究

本文分别以三苯胺、二甲基苯胺和吲哚啉单元为电子给体,设计并合成了3个新型D-π-A体系近红外敏化染料分子5C-1、5C-2和5C-3,并对其结构进行了表征,详细研究了在溶液中以及吸附到电极上的吸收光谱.该系列敏化染料在550—850 nm之间具有较强的吸收,尤其5C-3的吸收边带已达到954 nm.当该系列敏化染料吸附到TiO₂上时,吸收边带大幅红移,显示有利于染料捕获长波段区域的太阳光.通过循环伏安法,测定了染料的电化学性质,发现该系列敏化染料的最低未占有轨道(LUMO)能级与TiO₂导带并不匹配,因此选用导带能级更正的SnO₂作为阳极半导体材料进一步测试了该系列染料的光电性能,以发展具有优良性能的长波段响应的近红外敏化剂.     

Study on side‐chain second‐order nonlinear optical polyimides based on novel chromophore‐containing diamines. II. Copolyimides possessing direct photolithographic features

Second‐order nonlinear optical copolyimides were prepared from a novel chromophore‐containing diamine, 4‐nitro‐4′‐[N‐(4,6‐di‐4‐aminophenylamino)‐1,3,5‐triazin‐2‐yl]aminoazobenzene, a codiamine, 4,4′‐diamino‐3,3′‐dimethyldiphenylmethane, and benzophenone‐3,3′,4,4′‐tetracarboxylic dianhydride by a traditional two‐step process, which includes a solution polycondensation followed by a chemical imidization. Some of the polyimides (PIs) obtained possessed direct photolithographic features, and good photolithographic patterns were easily obtained. All PIs exhibited high‐glass transition temperatures (235–246 °C) and high thermal‐decomposition temperatures. They were also soluble in strong polar aprotic solvents such as N‐methyl‐2‐pyrrolidone, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, and γ‐butyrolactone. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1419–1425, 2001     

Solvent effects in the absorption spectra of the Ninhydrin chromophore

Visible spectra of the Ninhydrin chromophore, Ruhemann's purple, were studied in dimethyl sulfoxide (DMSO), formamide, N, N-dimethylformamide (DMF), and pyridine, as well as in mixed aqueous-nonaqueous solvent media. Large differences in both the position of absorption maxima and extinction coefficients for the two bands in the visible spectra in the various solvent media were observed. Both the absorption maxima and the extinction coefficients of the Ninhydrin chromophore were a linear function of the composition of dimethyl sulfoxide-H₂O solvent media. The experimental evidence allows predictions of values for the two absorption maxima of Ruhemann's purple as a function of the nature of the solvent medium. In nonaqueous aprotic solvents (i.e., DMSO and DMF), the maxima should be near 605 and 420 mμ; in nonaqueous aprotic solvents capable of undergoing charge-transfer interactions (i.e., pyridine), near 550 and 420 mμ; and in nonaqueous protic solvents (i.e., formamide), near 575 and 410 mμ. The maxima in aprotic media will be displaced to about 575 mμ (higher wavelength band) and 410 mμ (lower wavelength band) on dilution with protic solvents.     

SYNTHESIS AND CHARACTERIZATION OF ORGANSOLUBLE POLYIMIDE AND COPOLYIMIDES FROM ALICYCLIC DIANHYDRIDE

A kind of highly organsoluble polyimide and copolyimides were successfully synthesized from bicyclo（2.2.2）-oct- 7-ene-2,3,5,6-tetracarboxylic dianhydride （BCDA）, the commercial diamine 4,4＇-methylenedianiline （MDA） and the designed diamine 4,4＇-methylenebis-（2-tert-butylaniline） （MBTBA）. The polyimide from BCDA and MBTBA is highly soluble in conventional low boiling point solvents （such as chloroform, tetrahydrofuran） at room temperature. But the solubility of the copolyimides in conventional solvents decreased with the molar ratio of MBTBA and MDA decreased. When the molar ratio of MBTBA and MDA was larger than 7/3, the copolyimides can be soluble in low boiling point solvents at room temperature to form a transparent, flexible, tough film by solution casting. When the molar ratio of MBTBA and MDA was between 7/3 and 1/9, they can only be soluble in hot dipolar aprotic solvents （such as DMF, NMP etc.） and form films too. The copolyimide was only soluble in m-cresol when the molar ratio of MBTBA and MDA was lower than 1/9. The number-average molecular weights of the soluble copolyimides were larger than 5.8 × 1064 g/mol by GPC and their polydispersity indices were higher than 1.4. Only one glass transition temperature of these copolyimides was detected around 400℃ by DMA. The copolyimides did not show appreciable decomposition up to 430℃ in N2.     

FLUORINATED PHTHALAZINONE-CONTAINING COPOLYIMIDES FOR PASSIVE OPTICAL WAVEGUIDES

A series of fluorinated copolyimides containing phthalazinone moieties were prepared from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 3,3′4,4′-benzophenone-tetracarboxylic dianhydride (BPDA) and 2-(4-alninophenyl)-4-[4-(4-alninophenoxyl)phenyl]-2,3-phthalazin-1-one (DHPZ-2NH2) for making polymeric optical waveguides. The resulting copolymers containing 0-50mol% BPDA/DHPZ-2NH2 show good solubility and are soluble in some organic polar aprotic solvents. The copolyimides also present excellent thermal stability. These polymers possess high glass transition temperature higher than 603K and high decomposition temperature above 742K determined by differential scanning calorimetry and thermogravimetric analysis, respectively, under a nitrogen atmosphere. Their refractive indices could be controlled by varying the ratio of 6FDA and BPDA in the copolymer from 0.5 to 1.0, and the in-plane refractive indices (riTE) range from 1.6366 to 1.6668 and the out-of-plane refractive indices (nTM) from 1.6024 to 1.6280 at 632.8nm.The polymers birefringence (0.0342—0.0388) is almost independent of the 6FDA content of copolymer, which indicated that the phthalazinone-containing copolyimides could be suitable to fabricate optical waveguides possessing a low polarization dependent loss (PDL).     

Preparation and characterization of organosoluble copolyimides based on a pair of commercial aromatic dianhydride and one aromatic diamine, 1,2-bis(4-aminophenoxy)-4-tert-butylbenzene, series

 A series of copolyimides with high molecular weights, excellent mechanical properties, heat-resistant properties, and good solubilities in organic solvents were synthesized from six kinds of commercial dianhydrides and 1,2-bis(4-aminophenoxy)-4-tert-butylbenzene. Monomers for synthesizing insoluble polyimides and monomers for synthesizing soluble polyimides were used to synthesize semialternating copolyimides with arbitrary solubilities. Fifteen kinds of soluble copolyimides were synthesized through chemical or thermal cyclodehydration. These copolyimides were found to be easily soluble as well as able to be processed by casting from solutions such as N-methyl-2- pyrrolidone, N,N-dimethylacetamide, dimethylformamide, dimethyl sulfoxide, m-cresol, and tetrahydrofuran. The easily dissolved characteristics of this series of copolyimides stemmed from the tert-butyl group, the ortho-linked aromatic unit, and the ether group within 4-tert-butylbenzene. Besides, when the dianhydride molecules used contained organosoluble groups and were mixed at varying molar ratios, the solubilities in organic solvents could be greatly enhanced. The copolyimides could improve the processability of polymers, while maintaining or increasing their excellent mechanical properties and heat-resistant properties. Received: 21 July 2000 Accepted: 13 December 2000     

西红花酸二甲酯电子吸收光谱与热力学性质的理论研究

使用密度泛函理论B3LYP方法,对西红花酸二甲酯的结构、电子吸收光谱、热力学性质进行理论计算研究,并基于Tomasi的极化统一场模型(PCM)讨论溶剂效应.结果显示,溶剂对西红花酸二甲酯的前线分子轨道特征几乎无影响,溶剂作用使该分子的最大吸收波长红移约42 nm,红移程度与溶剂极性无关.西红花酸二甲酯分子的气态热力学性质与温度的关系式分别为:Cm p=189.782+0.925T,S m=457.503+1.366T,H m=1164.899+0.195T+4.671×10-4T2,Gm=1164.899-0.263T-8.989×10-4T2.298 K时,西红花酸二甲酯分子的气态标准摩尔生成焓和标准摩尔生成自由能分别为-1180.67和-733.23 kJ·mol-1.     

Solvent effects on the resonance Raman and hyper-Raman spectra and first hyperpolarizability of N,N-dipropyl-p-nitroaniline

Linear absorption spectra, resonance Raman spectra and excitation profiles, and two-photon-resonant hyper-Rayleigh and hyper-Raman scattering hyperpolarizability profiles are reported for the push-pull chromophore N,N-dipropyl-p-nitroaniline in seven solvents spanning a wide range of polarities. The absorption spectral maximum red shifts by about 2700 cm(-1), and the symmetric -NO2 stretch shifts to lower frequencies by about 11 cm(-1) from hexane to acetonitrile, indicative of significant solvent effects on both the ground and excited electronic states. The intensity patterns in the resonance Raman and hyper-Raman spectra are similar and show only a small solvent dependence except in acetonitrile, where both the Raman and hyper-Raman intensities are considerably reduced. Quantitative modeling of all four spectroscopic observables in all seven solvents reveals that the origin of this effect is an increased solvent-induced homogeneous broadening in acetonitrile. The linear absorption oscillator strength is nearly solvent-independent, and the peak resonant hyperpolarizability, beta(-2omega;omega,omega), varies by only about 15% across the wide range of solvents examined. These results suggest that the resonant two-photon absorption cross sections in this chromophore should exhibit only a weak solvent dependence.     

Synthesis and characterization of highly soluble fluorescent main chain copolyimides containing perylene units

A series of high molecular weight copolyimides containing various amount of perylene units in the main chain have been synthesized. The polymers were characterized by FT-IR, NMR, UV/Vis, fluorescence spectroscopy, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis measurements. They are highly soluble in conventional solvents such as CHCl₃, THF, cyclohexanone etc. and form optically transparent films by solution casting or spin coating. The incorporation of various amount of perylene units in the main chain allows the control of the fluorescence intensity in solution and in solid thin films. The copolyimide containing 0.28 mol% perylene units exhibits the highest solid-state fluorescence. The observed fluorescence intensities of the copolyimides in solid state film decreased with the increasing amount of perylene units in the main chain when the mole ratio of perylene units greater than 0.28 mol% indicating the aggregation of chromophores. The copolyimides are thermally stable up to 400 °C and exhibit glass transition temperatures in the range of 340-360 °C. The number average molecule weight ranges from 1.72×10⁴ to 1.25×10⁵ and the molecule weight distribution mediated between 1.9 and 2.4.     

Electrochemical studies of sulfonates in non-aqueous solvents: Part III. Trifluoromethanesulfonic acid as a strong acid in dipolar aprotic solvents and acetic acid

Dissociation of trifluoromethanesulfonic acid in non-aqueous solvents has been investigated mainly by conductometry and compared with that of p-toluenesulfonic, methanesulfonic, fluorosulfuric and perchloric acids. The solvents used are dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, n-butyronitrile, propylene carbonate, acetonitrile, nitromethane, methyl isobutyl ketone and acetic acid. Trifluoromethanesulfonic acid is completely dissociated in rather basic solvents such as dimethyl sulfoxide, dimethylacetamide and dimethylformamide, while it is associated to some extent in the other solvents, especially in methyl isobutyl ketone and acetic acid. The strength of trifluoromethanesulfonic acid is almost the same as that of perchloric acid in all the solvents. Dissociation constants of the other acids are also obtained.     

可溶性聚苯并噻吩的电化学合成

聚噻吩及其衍生物具有良好的导电性 ,优越的电致变色及荧光特性 ,可望用于研制各种新型微电子器件[1,2 ] .因此 ,这类聚合物的合成与表征一直受到广泛关注[3] .噻吩类聚合物是一个庞大的家族 ,其中聚异苯并噻吩早就被合成出来[4 ,5] .三氟化硼乙醚溶液 (ＢＦＥＥ)是电聚合芳香族化合物 (如噻吩、苯等 )的一种优良电解质[6～ 10 ] .在这一介质中 ,单体的氧化聚合电位很低 ,得到的导电高分子膜具有优良的机械力学性能 .本文将报道苯并噻吩在纯ＢＦＥＥ或ＢＦＥＥ与浓硫酸形成的混合电解质中的电化学聚合反应 .用这一方法合成得到了能发出蓝色…