含苯并咪唑单元可溶性聚酰亚胺的合成和性能

合成了一种刚性芳香二胺单体3,3',5,5'-四甲基-4,4'-二胺基苯基甲苯(BDAP),与6-氨基苯基-2-氨基苯并咪唑(BIA)组成混合二胺,分别与4种商品化的二酐单体(均苯四酸二酐(PMDA)、联苯四酸二酐(BPDA)、二苯酮四酸二酐(BTDA)和二苯醚四酸二酐(ODPA))一步法缩聚合成了一系列可溶性聚酰亚胺.采用FTIR,1H-NMR,UV-Vis,DMA和TGA等测试方法对所制备的聚酰亚胺进行了表征.结果表明,所制备的聚酰亚胺具有良好的溶解性能,能够在NMP和DMAc等常规溶剂中溶解;耐热性及力学性能优良,玻璃化转变温度超过410℃,分解温度在500℃以上.     

聚酰亚胺纤维及其纺丝工艺研究进展

聚酰亚胺纤维由于其优良的性能,已成为高技术纤维领域的研究热点之一.本文归纳了聚酰亚胺纤维的聚合单体,主要有二酐单体(均苯四甲酸酐、联苯四甲酸酐、二苯醚四酸二酐、二苯酮四酸二酐等)和二胺单体(二氨基二苯醚、对苯二胺、间苯二胺等).另外,还有第三单体,如嘧啶环二胺、氯化对苯二胺、二氨基二苯醚等,综述了聚酰亚胺纤维的主要纺丝...     

聚酰亚胺／SiO_2杂化材料的硅核磁共振波谱和电光性质的研究

以含氟的二胺5,5’-(六氟异丙基)-二-(2-氨基苯酚)(6FHP)及二酐4, 4’-(六氟异丙基)-苯二酸酐(6FDA)或均苯四甲酸酐(PMDA)为单体,以分散红 1(DR1)为活性生色分子合成具有非线性光学特性的含氟聚酰亚胺,并采用溶胶-凝胶(Sol-Gel)法合成相应的聚酰亚胺／SiO2杂化材料．采用固态29 Si MAS NMR谱研究了含氟聚酰亚胺／SiO2杂化材料的交联结构,结果表明杂化材料中是以T3、Q3、Q4结构为主,说明在杂化材料中形成了交联网状结构．采用衰减全反射(ATR)测定了聚酰亚胺和杂化材料在832 nm处的电光系数,其值分别为 32、28、34和29 pm／V,结果表明具有较高的电光系数．     

含磷聚酰亚胺纤维的制备与性能

合成了一种含磷二胺单体, 二(4-胺基苯氧基)苯基膦氧(DAPOPO). 该单体与4,4'-二胺基二苯醚(ODA)、 均苯四酸二酐(PMDA)和3,3',4,4'-联苯四酸二酐(BPDA)共聚得到聚酰胺酸溶液, 通过干喷湿纺法纺丝得到聚酰胺酸纤维, 聚酰胺酸纤维经过热亚胺化和热牵伸得到含磷的聚酰亚胺纤维. 利用纤维强度仪、 扫描电子显微镜、 热失重分析仪和氧指数测定仪等研究了含磷聚酰亚胺纤维的力学性能、 形貌、 热稳定性能和阻燃性能. 结果表明, 随着含磷量的增加, 纤维的热稳定性明显提高, 而极限氧指数从35上升到了45, 说明纤维的阻燃性能得到很大提高.     

不同比例的s-BPDA/i-BPDA型聚酰亚胺共聚结构与性能关系

由不同比例的二酐单体3,3′,4,4′-联苯四酸二酐(s-BPDA)/2,2′,3,3′-联苯四酸二酐(i-BPDA)与二胺单体4,4′-二氨基二苯醚(4,4′-ODA)制得了一系列共聚可溶聚酰亚胺. 采用DSC 、TGA和拉伸等测试方法对所得共聚聚酰亚胺进行了表征, 实验结果表明, 所得聚酰亚胺具有优异的力学性能和热稳定性, 并且随着i-BPDA含量的增加, 聚酰亚胺的溶解性提高, 玻璃化转变温度(Tg)升高, 中间体聚酰胺酸的固有黏度降低.     

4-苯乙炔基苯胺封端聚酰亚胺树脂的合成与性能研究

使用4-苯乙炔基苯胺(4-PEA)作为反应性封端剂,和3,3′,4,4′-二苯醚四酸二酐(ODPA),3,3′,4,4′-联苯四酸二酐(BPDA),1,4-双(4′-氨基-2′-三氟甲基苯氧基)苯(BTPB)和3,4′-二氨基二苯醚(3,4-′ODA)反应合成了系列4-苯乙炔基苯基封端的聚酰亚胺低聚物,对低聚物的化学结构、热性能和熔体粘度以及固化后树脂的热性能等进行了研究.实验结果表明,低聚物均具有一定的结晶性,含有ODPA的聚酰亚胺低聚物较之含有BPDA的低聚物具有更低的熔体粘度,且出现最低熔体粘度的温度更低;固化后的树脂表现出良好的热性能,含有BPDA的树脂具有更高的玻璃化转变温度;系列低聚物中二胺单体的比例对于低聚物的熔体粘度和固化后树脂的热稳定性有一定影响.     

含氟及硫醚基团聚酰亚胺光波导材料的合成及表征

通过分子设计,合成了含三氟甲基及硫醚基团的二胺单体4,4'-双(4-胺基-2-三氟甲基苯硫基)二苯硫醚(6FSEDA),利用其与6种芳香二酐单体:3,3',4,4'-联苯四羧酸二酐(BPDA)、4,4'-氧双邻苯二甲酸酐(ODPA)、3,3',4,4'-二苯酮四酸二酐(BTDA)、4,4'-(六氟异丙基)-苯二酸酐(6FDA)、3,3',4,4'-二苯硫醚四酸二酐(DTDA)及3,3',4,4'-二苯砜四酸二酐(DSDA)经一步法合成了一系列含氟及硫醚基团的聚酰亚胺(PI),并对其结构与性能进行了研究.结果表明,该系列PI的玻璃化温度Tg(DSC)在199.8～231.7℃范围,5%和10%热失重的温度(N2氛围)分别在491℃和517℃以上,在400～700 nm的可见光波长范围内具有优异的光学透明性,在光通讯波段(1310 nm和1550 nm处)均无明显吸收,且在这两个波长处测得的平均折射率范围分别为1.5401～1.6142和1.5389～1.6124,在波长632.8 nm测得的双折射范围为0.0012～0.0045.可见,含氟及硫醚基团聚酰亚胺薄膜具有良好的热稳定性和光学性能.     

含全氟环丁烷环可溶性聚酰亚胺的合成与表征

以乙酰氨基苯酚为原料,经过BrCF2CF2Br氟烷基化、Zn催化脱卤、热环化二聚,以及水解去保护,合成了一种含全氟环丁烷环的二胺单体1,2,3,3,4,4-六氟-1,2-双[4-(氨基)苯氧基]环丁烷.用该单体分别与酯环二酐双环[2·2·1]辛烷-2,3,5,6-四羧基2,3,5,6-二酐(BHDA)、芳香性二酐3,3′,4,4′-联苯四酸二酐(BPDA)和3,3′,4,4′-二苯酮四酸二酐(BTDA)通过“一步法”制备了3种新型含全氟环丁烷环聚酰亚胺.通过粘度测试、溶解性实验、FT-IR、热失重分析(TGA)和差热扫描量热(DSC)分析等手段,对所合成的聚酰亚胺的结构与性能进行了表征.结果显示该类聚酰亚胺可溶于大多数常用极性有机溶剂,热分解温度高于480℃,其中两种聚合物玻璃化温度低于150℃,表明含全氟环丁烷环聚酰亚胺具有良好的溶解性和可加工性.     

可溶性聚酰亚胺的制备及其在液晶显示器上的潜在应用

以3,5-二硝基苯甲酰氯和4-羟基联苯为原料,合成了功能性二胺单体3,5-二氨基苯甲酸联苯酯(DABBE).用此单体与3,3′-二甲基-4,4′-二氨基二苯甲烷(DMMDA)、3,3′,4,4′-二苯醚四甲酸二酐(ODPA)共缩聚,采用低温缩聚-化学亚胺化的方法,通过调节共聚物组成制备了5种聚酰亚胺(PI).利用FT-IR、NMR、UV-Vis与DSC等手段对合成二胺单体及聚酰亚胺进行了结构表征和性能测试;研究了其溶解性能、透光性能、取向性能和耐热性能.结果表明,5种聚酰亚胺均可溶于NMP、DMF等极性溶剂;对液晶分子取向时的预倾角随DABBE的比例增加而增大,可达1.8°.但当DABBE的比例增加时,PI的分子量降低,将影响其成膜性能.此外,实验所得的PI透过率大于80%,玻璃化转变温度在220℃以上.     

一种可溶性聚酰亚胺的合成及其渗透汽化脱有机硫化物性能测试

由3,3′,4,4′-二苯醚四甲酸二酐(ODPA)和3,3′-二甲基4,4′二氨基二苯甲烷(DMMDA)二胺为单体,利用低温溶液缩聚化学亚胺化法合成了ODPA DMMDA聚酰亚胺.利用FT IR、NMR与DSC等手段对聚酰亚胺的结构进行了表征;研究了其溶解性能、耐热性能和力学性能.结果表明,此聚酰亚胺可溶于DMF、DMAc等极性溶剂;玻璃化转变温度为264℃,其10%的热分解温度为521℃;断裂强度为137MPa;断裂伸长率为18%.采用相转化法将其制成非对称膜,采用扫描电子显微镜(SEM)观察内部结构,在渗透汽化脱硫实验中,对噻吩有良好的选择透过性能.350K时,硫富集率为3.68,渗透通量为0.92kg m2h.     

Preparation and characterization of polyimide/mesoporous silica hybrid nanocomposites based on water-soluble poly(amic acid) ammonium salt

Recently, mesoporous silica was blended with polyimide to develop low dielectric constant (k) materials with improving mechanical and thermal properties of polyimide by utilizing both the nanoporous structure and silica framework. However, even the use of mesoporous silica did not show a significant decrease of k due to the phase segregation in between polyimide and the mesoporous silica materials. In this work, we attempted to prepare polyimide/mesoporous silica hybrid nanocomposites having relatively good phase mixing behavior by utilizing polyimide synthesized from a water soluble poly(amic acid) ammonium salt, which lead to low k up to 2.45. The thermal properties of polyimide were improved by adding mesoporous silicas. For this work, we have fabricated mesoporous silicas through surfactant-templated condensation of tetraethyl orthosilicate (TEOS). Pyromellitic dianhydride (PMDA)-4,4′-oxydianiline (ODA) polyimide was prepared from poly(amic acid) ammonium salt, which had been obtained by incorporating triethylamine (TEA) into PMDA-ODA poly(amic acid) in dimethylacetamide (DMAc), followed by thermal imidization.     

Effect of carbon nanotubes and their dispersion on thermal curing of polyimide precursors

The process of thermal imidization reaction is significant for temperature and time control in the polyimide industry. Here, we report the effect of carbon nanotubes and their states of dispersion on the thermal imidization of the precursor films of polyimide (poly(amic acid)) for the first time. The curing process was followed by measuring Fourier transform-infrared (FT-IR) spectra, fluorescence spectra, thermogravimetric-differential scanning calorimeter (TG-DSC) properties and the refractive indices of films. It was found that by evenly dispersing 1 wt% of carbon nanotubes assisted by a dispersant in the poly(amic acid),the full imidization temperature of the polyimide can be reduced from 300 °C to 250 °C. Different states of distribution of CNTs were observed by light microscopy and scanning electron microscopy, and proved that a better dispersion of carbon nanotubes dramatically enhanced the speed of imidization. Moreover, the DSC results showed that lower decomposition temperature of poly(amic acid) could be obtained with more uniform distribution of carbon nanotubes, which means the process of cyclodehydration of the poly(amic acid) was accelerated.     

Two‐step thermal conversion from poly(amic acid) to polybenzoxazole via polyimide: Their thermal and mechanical properties

Poly(amic acid) was synthesized with a low‐temperature solution polymerization of 3,3′‐dihydroxybenzidine and pyromellitic dianhydride in N,N‐dimethylacetamide. The cast films were thermally treated at various temperatures. The polyimide containing the hydroxyl group was rearranged by decarboxylation, resulting in a fully aromatic polybenzoxazole at temperatures higher than 430 °C. These stepwise cyclizations were monitored with elemental analysis, Fourier transform infrared, and nuclear magnetic resonance. Microanalysis results confirmed the chemical compositions of poly(amic acid), polyimide, and polybenzoxazole, respectively. A cyclodehydration from poly(amic acid) to polyimide occurred between 150 and 250 °C in differential scanning calorimetry, and a cyclodecarboxylation to polybenzoxazole appeared at 400–500 °C. All the samples were stable up to 625 °C in nitrogen and displayed excellent thermal stability. Polybenzoxazole showed better thermal stability than polyimide, but polyimide exhibited better mechanical properties than polybenzoxazole. However, polyimide showed a crystalline pattern under a wide‐angle X‐ray, whereas polybenzoxazole was amorphous. The precursor poly(amic acid) was readily soluble in a variety of solvents, whereas the polyimide and polybenzoxazole were not soluble at all. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 2537–2545, 2000     

聚酰胺酸结构及其亚胺化的红外光谱分析

利用变温透射红外光谱方法,通过跟踪聚酰胺酸（PAA）的亚胺化过程,对由均苯四酸二酐和4,4′-二氨基二苯醚合成的聚酰胺酸及经过加热亚胺化后生成的聚酰亚胺(PI)的红外吸收光谱进行分析,对聚酰胺酸和聚酰亚胺的红外谱峰进行合理的归属,发现聚酰胺酸在亚胺化过程中有-COO-和-NH+2存在,-COO-中羰基的对称与反对称伸缩振动分别位于1607和1406 cm-1,NH+2的伸缩振动则有3200、3133、2938、2880、2820和2610 cm-1等多个精细谱带。 并根据对-COO-和-NH+2谱峰的归属,提出聚酰胺酸生成聚酰亚胺的机理为聚酰胺酸中COOH的H+转移到聚酰胺酸中的NH上,形成NH+2,然后脱水环化生成聚酰亚胺。     

Blend of polyimide having internal acetylene units and oligoimide end-capped with biphenylenes

A N-Methylpyrrolidone (NMP) solution of polymic acid having internal acetylene units in the backbone was mixed with a NMP solution of oligomeric amic acid end-capped with biphenylenes to afford a miscible solution. The viscosity of polymic acid solution lowered considerably by the addition of oligomers, which could lead to improved processability. The amic acid mixture was thermally or chemically cyclized to give a blend of internal-reactive polymide and end-reactive oligoimide. Films of imide blends were easily prepared by casting solutions of the amic acid blends followed by imidization. The imide blends were thermally cured at 400°C for 10 min to give cross-linked polyimides that showed excellent thermal stability as confirmed by DSC, TGA, TMA, and viscoelastic analyses of the cured films. A selective co-crosslinking reaction between biphenylene in the oligomide and acetylene in the polyimide to give phenanthrene linkage is supposed to be the cause of the high thermal stability.     

Preparation and photophysics of polyimide/silica organic/inorganic hybrid composites

In this work, polyimide/silica hybrid composites were prepared by the sol-gel reaction of tetraethoxysilane(TEOS) and the thermal imidization of poly(amic acid) from 3,3′,4,4′-biphenyltetracarboxylic dianhydride(BPDA) and 4,4′-oxydianiline(ODA), and their photophysical properties were investigated using a fluorescence spectroscopy. It was found that the intrinsic fluorescence of poly(4,4′-oxydiphenylene-3,3′4,4′-biphenyltetracarboximide)(BPDA-ODA) such as emission intensity and emission wavelength depends strongly on the changes in the molecular conformations during the sol-gel reaction and the thermal imidization. In conclusion, we found that the fluorescence spectroscopy can provide an insight into how the intermolecular or intramolecular interaction of polyimide in the hybrid composite system is affected by the silica contents, depending on the sample states.     

Characterization of a thermally imidized soluble polyimide film

A soluble aromatic poly (amic acid) film was converted to a soluble polyimide by staging at 25°C intervals to 325°C and characterized at each interval by several analytical methods. The behavior observed was consistent with an interpretation that a reduction occurred in molecular weight of the poly (amic acid) during the initial stages of cure before the ultimate molecular weight was achieved as a polyimide. This interpretation was supported by the results of solution viscosity, gel permeation chromatography, low angle laser light scattering photometry, and infrared spectroscopy analyses. The results of this study serve to increase our fundamental understanding of how polyimides are thermally formed from poly (amic acid)s.     

Synthesis and characterization of thermally crosslinked polyimide with second-order nonlinear optical chromophore

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溶胶凝胶法合成聚酰亚胺二氧化钛杂化膜

溶胶凝胶法制备了负载型聚酰亚胺 二氧化钛杂化膜 ,采用扫描电镜、红外光谱、TG DTA、压汞法和气体渗透性能测试装置对膜材料的表面形貌、表面结构、热性能、孔径分布和气体渗透性能进行了表征 .结果表明 ,杂化膜材料形成了有机相包裹无机相的交联结构 ;聚酰亚胺与二氧化钛粒子形成了新型键联结构 ;其热分解温度随二氧化钛含量的增加而降低 ,在 4 5 0℃以下热稳定性优于聚酰亚胺膜材料 ;平均孔径随二氧化钛含量增大而增大 ,孔径分布趋于弥散 ;N2 、H2 和CO2 在膜内渗透由Knudsen扩散控制 ,H2 O N2 分离因子均大于Knudsen扩散值 ,表现出良好的亲水性 .     

Mesoscopic Simulation Assistant Design of Immiscible Polyimide/BN Blend Films with Enhanced Thermal Conductivity

The mesoscopic simulation technique was applied to describe the phase separation behavior of polyimide blends and used for design of immiscible polyimide/BN blend films with enhanced thermal conductivity. The simulation equilibrium morphologies of different poly(amic acid)(PAA) blend systems were investigated and compared with optical images of corresponding polyimide blend films obtained by experiment. The immiscible polyimide blend films containing nano-/micro-sized BN with vertical double percolation structure were prepared. The result indicated that the thermal conductivity of polyimide blend film with 25 wt% nano-sized BN reached1.16 W/(m·K), which was 236% increment compared with that of the homogenous film containing the same BN ratio. The significant enhancement in thermal conductivity was attributed to the good phase separation of polyimide matrix, which made the inorganic fillers selectively localized in one continuous phase with high packing density, consequently, forming the effective thermal conductive pathway.