Cresylic soluble polyimides

Polyimides are prepared by reaction of dianhydrides with aromatic diamines under dehydrating conditions to insure conversion of the polyamic acids to polyimides. Cresylic acid solubility is observed only for cyclopentane dianhydride and benzophenone dianhydride. Most of the batches are made from BPDA, since it is the preferred dianhydride for thermal stability. Of 19 aromatic diamines only 2,4- and 2,6-diaminotoluene, 2,4-diaminoanisole, 4,5-dimethyl-1,2-phenylene diamine and 1,5-diamino-4,8-dihydroxyanthraquinone contribute a great deal toward making soluble polyimides of BPDA. 2,4-Diamino-acetanilide when used as the only diamine also gives a soluble polyimide with BPDA. The solubility of polyimides can be correlated with their solubility parameters, their symmetry, and their tendency to hydrogen bond.     

高羟基含氟丙烯酸乳液的合成及性能研究

以丙烯酸酯类单体作为原料,以过硫酸钾为引发剂,采用预乳化半连续乳液聚合方式合成了高羟基丙烯酸乳液,并在后期补加氧化还原体系引发剂,提高了单体的转化速率。系统地研究了乳化剂用量、羟基单体、氟单体、硅单体含量等因素对涂膜性能的影响。最后,将制备的丙烯酸羟基组分同水性固化剂配制成双组分水性丙烯酸聚氨酯清漆,并分析清漆的性能。     

Preparation and characterization of soluble polyimides

Two kinds of soluble polyimides from pyromellitic dianhydride with Congo red and 4-sulfanilamide were prepared, respectively. Their structures were characterized by IR and ¹H-NMR, and the thermal properties were investigated by DSC and TG–DTA. © 1995 John Wiley & Sons, Inc.     

Synthesis of highly soluble and transparent polyimides

A novel aromatic diamine, 3,3′‐diisopropyl‐4,4′‐diaminophenyl‐4″‐methyltoluene with a 4‐methylphenyl pendant group and isopropyl side groups, was designed and synthesized in this study. Then it was polymerized with various aromatic dianhydrides including pyromellitic dianhydride, 3,3′,4,4′‐biphenyltetracarboxylic dianhydride, 4,4′‐oxydiphthalic anhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride via a one‐pot high temperature polycondensation procedure to produce a series of aromatic polyimides. These polyimides exhibited excellent solubility even in common organic solvents, such as chloroform and tetrahydrofuran. The flexible and tough films can be conveniently obtained by solution casting. The films were nearly colorless and exhibited high optical transparency, with the UV cutoff wavelength in the range 302–365 nm and the wavelength of 80% transparency in the range 385–461 nm. Moreover, they showed low dielectric constants (2.73–3.23 at 1 MHz) and low moisture absorption (0.13%–0.46%). Furthermore, they also possessed good thermal and thermo‐oxidative stability with 10% weight loss temperatures (T_10%) in the range 489–507 °C in a nitrogen atmosphere. The glass transition temperatures of all polyimides are in the range 262–308 °C. Copyright © 2012 Society of Chemical Industry     

可溶性透明聚酰亚胺研究进展

芳香聚酰亚胺在有机溶剂中通常是不溶的,并且光学透明性低,这些事实限制了它们在某些领域中的实际应用,因此合成可溶性透明聚酰亚胺成为研究者们研究的热点。笔者从聚酰亚胺有色的原因及透明化、聚酰亚胺可溶性的改善与分子设计、可溶性透明聚酰亚胺的合成与表征、可溶性透明聚酰亚胺的应用4个方面进行了综述,给那些对可溶性透明聚酰亚胺感兴趣的研究者提供了基本的有价值的信息。     

含氟聚酰亚胺的设计、合成及应用性能研究进展

聚酰亚胺作为结构独特的一类功能性高分子材料,应用广泛.随着人们对材料综合性能要求的提高,含氟聚酰亚胺颇受业界关注.聚酰亚胺结构中引入氟原子既能提高材料溶解性和透光率,还能降低其吸湿率和介电常数.综述了近年来含氟聚酰亚胺在设计、合成和应用性能方面的研究进展,指出其结构设计带来的性能优势.特别是对含氟聚酰亚胺的溶解性、光学...     

含氟聚酰亚胺的设计、合成及应用性能研究进展

聚酰亚胺作为结构独特的一类功能性高分子材料,应用广泛。随着人们对材料综合性能要求的提高,含氟聚酰亚胺颇受业界关注。聚酰亚胺结构中引入氟原子既能提高材料溶解性和透光率,还能降低其吸湿率和介电常数。综述了近年来含氟聚酰亚胺在设计、合成和应用性能方面的研究进展,指出其结构设计带来的性能优势。特别是对含氟聚酰亚胺的溶解性、光学性能、热性能等进行了总结。展望了其在柔性显示面板/基板市场的应用发展方向。     

Modification of cyanate ester resin by soluble polyimides

Soluble polyimides (PIs) were prepared as random or multiblock types with 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (s‐BPDA) as acid dianhydride components and 4,4′‐bis(m‐aminophenoxy) diphenyl sulfone (m‐BAPS) as a diamine component by a one‐pot process and used to improve the brittleness of the cyanate ester resin. Random‐type PIs were more effective as modifiers than multiblock‐type PIs. The morphologies of the modified resins depended on PI structure, molecular weight, and concentration. The most effective modification of the cyanate ester resin was attained because of a heterogeneous phase structure composed of a flat matrix phase and phase‐inverted structures of the modified resin; a 15 wt % inclusion of a random PI (weight‐average molecular weight = 63,400) composed of 6FDA, s‐BPDA, and m‐BAPS (0.5/0.5/1.0 molar ratio) led to a 65% increase in the fracture toughness for the modified resin with a slight loss of flexural strength and a retention of flexural modulus and glass‐transition temperature, compared with the values for the unmodified resin. Water absorptivity of the modified resin was comparable to that of the unmodified resin up to 400 h, and then, water absorption of the modified resins increased considerably. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1–11, 2003     

Preparation of soluble polyimides and ultrafiltration membrane performances

Various soluble polyimides with bis[4‐(3‐aminophenoxy)phenyl]sulfone and three kinds of dianhydrides were prepared in a polar N‐methyl‐2‐pyrrolidone solvent by the traditional chemical two‐step method. All the polymers synthesized had good solubilities in polar solvents and excellent thermal properties. Wide‐angle X‐ray diffraction studies showed that all polyimides were amorphous. Polyimide ultrafiltration asymmetric membranes were successfully prepared by the traditional phase‐inversion method. The cross sections of the polyimide ultrafiltration membranes showed a very thin surface layer and a porous sublayer. The pure water flux was very high and the solute rejection rate at poly(ethylene glycol) of MW 20,000 was above 90%. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1–9, 2000     

Synthesis and characteristics of organic soluble photoactive polyimides

Soluble aromatic polyimides with inherent viscosities of 0.23–0.50 dL/g have been synthesized from 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (BAPAF) and various aromatic tetracarboxylic dianhydrides. Almost all polyimides were soluble in a wide range of organic solvents, i.e., acetone, m-cresol, N,N-dimethylacetamide, N,N-dimethylformamide, N,N-dimethylsulfoxide, N-methyl-2-pyrolidone, methyl ethyl ketone, and tetrahydrofuran (except that polyimide deriven from 3,3′,4,4′-biphenyl tetracarboxylic dianhydride). Synthesized polyimides have a glass transition temperature in a range of 293 to 355°C, showing no appreciable weight loss up to 400°C in both air and nitrogen. These soluble polyimides exhibit high transparency in the UV visible region, with water absorption being between 3.6 to 5.7 wt %. They provide an aqueous base developable positive photoresist system when formulated with diazonaphthoquinone sensitizer. On the other hand, negative photoactive polyimides which are soluble in common organic solvents and optically transparent at a light of 365 nm wavelength, being obtained by reacting these soluble polyimides with methacryloyl chloride. Properties and characteristics of both positive and negative photoactive polyimides have been studied here. © 1994 John Wiley & Sons, Inc.     

Syntheses of novel soluble carborane polyimides with ultrahigh thermal stability

Novel carborane polyimides were synthesized and studied. Aromatic meta‐carborane diamines of different structures were initially prepared. Polymerization of these new diamines with the commercially available 4,4′‐oxydiphthalic dianhydride led to meta‐carborane polyimides with various structures and thermal properties. The amorphous polymers obtained are of moderate molecular weight and show good solubility in organic solvents. Thermal analyses of these polyimides reveal that they have moderate to ultrahigh thermal stability depending on their specific structures, with 5% decomposition temperatures ranging from 382 to 786 °C in nitrogen. Different thermal properties of these polyimides are observed when the analyses are performed in dry air, with 5% decomposition temperatures shifting to temperatures ranging from 388 to 1128 °C. Due to the ever‐present requirement of higher performance polymers in fields like aerospace and defense, the methods developed here could be an impetus for the development of these industries. © 2015 Society of Chemical Industry     

Synthesis and characterization of organo‐soluble fluorinated polyimides

A novel fluorinated diamine monomer with a keto group, 4‐[4‐amino‐2‐trifluoromethyl phenoxy]‐4′‐[4‐aminophenoxy]benzophenone (ATAB) was prepared by reacting dihydroxybenzophenone with 4‐chloronitrobenzene and 2‐chloro‐5‐nitrotrifluoromethylbenzene in the presence of potassium carbonate followed by catalytic reduction with palladized carbon (10%). Fluorinated polyimides IVa–e were synthesized from the diamine mentioned above via a two‐step method (thermal and chemical imidization). Polyimides IVa–e have inherent viscosities in the range 0.65–1.06 dL g^?1 (thermal imidization) and 0.82–1.56 dL g^?1 (chemical imidization). The polyimides prepared by chemical imidization exhibit excellent solubility. Polyimide films exhibit tensile strength, elongation and tensile modulus in the ranges 96–106 MPa, 9–13% and 1.1–1.7 GPa, respectively. The T₁₀ values of the polyimides are in the range 540–598 °C in nitrogen and 545–586 °C in air, with more than 50–60% char yield. They have T_g values between 244 and 285 °C. The prepared polyimides show cut‐off wavelengths in the range 365–412 nm and transmittance at 450 nm in the range 80.9–94.2%. The dielectric constants of the polyimide films are in the range 3.10–3.77 at 1 kHz and 3.04–3.66 at 10 kHz, with moisture absorption of 0.14–0.40%. Copyright © 2006 Society of Chemical Industry     

Preparation and properties of soluble and colorless fluorine-containing photoreactive polyimide precursors

Photoreactive polyimide precursors, which are readily soluble in common organic solvents and optically transparent at light of 365 nm wavelength (i-line), similar to aliphatic polyimide precursors, were obtained by polycondensation of biphenyltetracarboxylic dianhydride (BPDA) and fluorine-containing diamine compounds. In particular, the polyimide precursor prepared from 2,2 bis(3-amino-4-methylphenyl) hexatluoropropane showed high solubility in common organic solvents and complete transparence at i-line wavelength. A 3 μm thick film of the polyimide precursor on a silicon wafer was exposed and developed, and offered high resolution (0.5μm line) patterns with an aspect ratio of 6.0. This polymide precursor swells very little in the developing solvent, resulting in the high resolution. Conversion of polyamic acid to polyimide at several curing temperatures was observed by infrared spectrophotometer and thermogravimetry.     

Synthesis and characterization of soluble polyimides and its ultrafiltration membrane performances

Soluble polyimides were synthesized and characterized from two diamines and four dianhydrides by the two- and the one-step method. Most of the polyimides could be soluble by one-step method except α,α′-bis(4-aminophenyl)-1,4-diisopropyl benzene/3,3′,4,4′-benzophenonetetracarboxylic dianhydride system in limited organic solvents. Glass transition temperatures ranged from 186 to 233°C and crystalline melt temperatures were not observed. All the soluble polyimides showed good thermal, mechanical, and electrical properties. The polyimides did not have crystalline structure and limited solubilities. The effective solvent had a medium dispersion component associated with weak polar and hydrogen components. The polymer from one-step polymerization had a narrower molecular weight distribution than the two-step method. Polyimide synthesized with 4,4′-oxydiphthalic anhydride and bis[4-(3-aminophenoxy)phenyl]sulfone by two-step method could only be prepared by the typical phase inversion method. Other membranes except this polyimide membrane could not be prepared by the typical phase-inversion method because of poor solubility about polar solvents. The flux of this ultrafiltration membrane was very high, and this membrane could especially retain polymer having a molecular weight 20,000 to above 90%. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 907–918, 1999     

Gas transport properties of soluble aromatic polyimides with sulfone diamine moieties

Aromatic polyimides derived from 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 3,3′- or 4,4′-diaminodiphenylsulfone (m-DDS or p-DDS) have been synthesized with a chemical imidization. The disappearance of amic acid groups and the appearance of imide groups are determined by IR and ¹H-NMR spectroscopies. The obtained polyimides are amorphous and soluble in organic solvents. The gas transport properties of the polyimide membranes to CO₂, O₂, N₂, and CH₄ have been determined at 35°C and at a pressure up to 10 atm. The (PCO₂/PCH₄) and (PO₂/PN₂) selectivities of the membranes are augmented due to their large gas diffusivity selectivities. This is considered to be due primarily to the high packing density of polymer chain. © 1995 John Wiley & Sons, Inc.     

Studies on high performance nonvolatile polyimides coating: Gamma ray initiated bulk copolymerization of vinyl polar monomer and maleimide-terminated polyimides with flexible backbone and the modifications

The objective of the present work was to develop a nonvolatile coating involving vinyl polar monomer and high performance maleimide-terminated polyimides (MTPs) with flexible backbone. The synthesized MTPs with different molecular weight (Mw) showed good solubility in N-vinylpyrrolidone (NVP), and the homogeneous binary systems were obtained even when the content of MTPs reached 50 wt%. NVP-MTPs copolymer resin were prepared by gamma ray initiated bulk copolymerization, followed by thermal postcuring to improve the properties. NVP-MTPs copolymer resins exhibited flexural strength higher than 76 MPa, glass transition (T_g) higher than 142 °C, thermal stability (T_5%) no less than 214 °C, but relatively poor impact strength and water resistance property. It was revealed that increasing Mw of MTPs would result in the increase of impact strength and a decrease of thermal and flexural properties of copolymer resin, accompanied with the gradual decrease of gel percentage of copolymer resin. Amino-terminated linear polyimide (ATLP) was introduced to modify NVP-MTPs copolymer resin and the C-N linkage was formed from terminal NH₂ to electron deficient double bone on maleimide ring of MTPs via Michael nucleophilic addition. Polyvinylsiloxane (PVS) were introduced to modify NVP-MTPs copolymer resin by in situ ring opening polymerization followed with copolymerization under gamma ray initiation. The introduction of both modifiers led to an appreciable increase of impact strength and a remarkable water uptake decrease, meanwhile, other properties including thermal and flexural properties of modified copolymer resins maintained and even exhibited a slight increase. Fracture surface morphology by scanning electron microscopy (SEM) technique showed that introduction of both modifiers maintained good homogeneity of copolymer resin, and led to a gradual transition from rigid deformation to plastic deformation.     

Synthesis and characterization of new soluble and thermostable polyimides via novel diisocyanates

A facile synthesis of two novel diisocyanates containing methylene groups and preformed imide structure is described. Furthermore, six thermally stable and soluble polyimides were synthesized by polycondensation of these two diisocyanates with pyromellitic dianhydride (PMDA), 3, 3 ′,4, 4 ′‐benzophenonetetracarboxylic dianhydride (BTDA) and hexafluoroisopropylidene‐2,2‐bis‐(phthalic anhydride) (6FDA) in N,N ‐dimethyl acetamide. All monomers and polymers were characterized by conventional methods and their physical properties such as solution viscosity, solubility properties, thermal stability and thermal behaviour were studied. © 1999 Society of Chemical Industry     

Synthesis and properties of novel soluble polyimides having a spirobisindane-linked dianhydride unit

A new synthetic procedure was elaborated allowing the preparation of semiaromatic dianhydride. N-Methyl protected 4-chlorophthalic anhydride was nitrated with HNO₃ to produce N-methyl-4-chloro-5-nitrophthalimide (1). The aromatic nucleophilic substitution reaction between 5,5′,6,6′-tetrahydroxy-3,3,3′,3′-tetramethyl-1,1-spirobisindane and 1 afforded spirobisindane-linked bis(N-methylphthalimide) (2), which was hydrolyzed and subsequently dehydrated to give the corresponding dianhydride (3). The latter was polymerized with five different aromatic diamines to afford a series of aromatic polyimides. The properties of polyimides such as inherent viscosity, solubility, UV transparency and thermal stability were investigated to illustrate the contribution of the introduction of spirobisindane groups into the polyimide backbone. The resulting polyimides were readily soluble in polar solvents such as chloroform, THF and N-methyl-2-pyrrolidone. The glass-transition temperatures of these polyimides were in the range of 254-292 °C. The tensile strength, elongation at break, and Young's modulus of the polyimide film were 68.8-106.6 MPa, 5.9-9.8%, 1.7-2.0 GPa, respectively. The polymer films were colorless and transparent with the absorption cutoff wavelength at 286-308 nm.     

基于酚酞结构高可溶性聚酰亚胺的合成与性能

以百里香酚酞、对氟硝基苯为起始原料,通过芳香亲核取代和氧化还原反应得到新型芳香二胺单体5,5’-二异丙基-4,4’-二氨基苯氧基-2,2’-二甲基酚酞。该二胺单体分别与3,3’,4,4’-二苯醚四甲酸二酐、3,3’,4,4’-二苯酮四羧酸二酐和3,3’,4,4’-联苯四甲酸二酐以一步法高温缩聚制得了一系列同时含酚酞Cardo结构及异丙基和甲基侧基的高可溶性聚酰亚胺(PI-1、PI-2和PI-3)。该系列聚酰亚胺具有优异的溶解性,室温下不仅可溶于高沸点溶剂N-甲基吡咯烷酮、N,N-二甲基乙酰胺、N,N-二甲基甲酰胺、二甲基亚砜,而且能溶于低沸点溶剂氯仿,二氯甲烷和四氢呋喃,可通过其溶液浇铸制得一系列高性能聚酰亚胺薄膜。所制聚酰亚胺薄膜具有较高的光学透明性,截断波长在324～365 nm之间,450 nm的透过率在56%～78%之间。该系列薄膜玻璃化转变温度在266～289℃之间,在N₂和O₂下10%热失重温度均≥432℃。其拉伸强度在77～95 MPa之间,断裂伸长率在9.1%～13.0%之间,1 MHz下介电常数为2.79～3.01 F/m,...     

高憎水性含氟丙烯酸树脂及其涂料的制备

以甲基丙烯酸甲酯、丙烯酸丁酯、甲基丙烯酸羟乙酯以及两种不同氟链段长度的丙烯酸酯单体,先通过自由基聚合,再用一种氟碳改性剂对其进行化学改性,制得了一种高憎水性的含氟丙烯酸树脂。利用红外光谱、接触角仪、原子力显微镜、X射线光电子能谱仪等对树脂和涂层性能进行了表征。研究表明:氟碳改性剂的加入可明显降低涂层表面能,增大涂层接触角,但当加入量大于1.8%时,继续增加氟碳改性剂用量对接触角影响不大。