Synthesis and characterization of polyimides from 9,10-diphenoxy-1,2,3,4,5,6,7,8-octahydro-2,3,6,7-anthracenetetra-carboxylic 2,3:6,7-dianhydride

Summary A new dianhydride containing phenoxy groups and alicyclic unit was prepared by a bis-Diels-Alder reaction of 1,4-diphenoxy-2,3,5,6-tetrakis(bromomethyl)benzene with maleic anhydride, and polymerized with various aromatic diamines in one step at high temperature in NMP. All the polymers had good solubility toward polar solvents and their inherent viscosities were in the range of 0.31∼0.53dL/g. Polyimides properties were investigated and discussed in terms of the chain structures resulting from the incorporation of different diamines. All the polyimides were thermostable up to 475°C with 10% weight loss and in DSC thermograms the polymers exhibited T _gs between 249 and 317°C. Received: 29 January 2001/Revised version: 25 April 2001/Accepted: 27 April 2001     

Synthesis and characterization of polyimides from 9,10-diphenyl-1,2,3,4,5,6,7,8-octahydro-2,3,6,7-anthracenetetracarboxylic 2,3:6,7-dianhydride

Summary A new dianhydride containing pendent phenyl group and alicyclic unit was prepared by a bis-Diels-Alder reaction of 1,4-diphenyl-2,3,5,6-tetrakis(bromomethyl)benzene with maleic anhydride, and polymerized with various aromatic diamines in one step at high temperature in NMP. Polymers were soluble in NMP and their inherent viscosities were in the 0.29∼0.47 dL/g range. Polyimides properties were investigated and discussed in terms of the chain structure resulting from the incorporation of different diamines. Received: 22 February 2002/Revised version: 26 March 2002/ Accepted: 4 April 2002     

Synthesis and characterization of polyimides from 1,4-bis[4-(n-alkyloxy)phenyloxy]pyromellitic dianhydrides and 4,4'-oxydianiline

Summary New pyromellitic dianhydrides having (n-alkyloxy)phenyloxy (-O-Ph-O-n-C_mH_2m+1, m=1,4,8,12) side chains were synthesized and polymerized with 4,4'-oxydianiline (ODA) in NMP at room temperature. Imidization was carried out using triethylamine and acetic anhydride. The synthesized polyimides (C_m-OPIs) were characterized and their properties were measured and discussed in respect to the effects of side chains. Inherent viscosities of the polymers were in the 0.46 – 0.68 dL/g range. All the polymers were highly soluble in N-methylpyrrolidinone (NMP) and slightly soluble in DMSO, m-cresol, DMF and concentrated H₂SO₄ at room temperature. TGA pyrograms showed two-step degradation. In DSC thermograms the polymers exhibited T_g's between 219°C and 305°C and melting points near 350°C were observed in C₈- and C₁₂-OPIs. Wide-angle X-ray diffractometry for as-polymerized samples revealed very low crystallinities and layered structures which were better developed in the polymers with longer side chains. Received: 11 November 1997/Revised version: 4 December 1997/Accepted: 9 December 1997     

长链聚酰亚胺的制备与表征

以长链二胺4,4' 二(4 氨基苯氧基)二苯砜(BAPS)为单体,采用两步法分别与二酐PMDA、ODPA、BPADA合成了3种链长的聚酰亚胺。实验利用GPC监测0 05mol/L聚酰胺酸(PAA)的数均聚合度(Xn)及相对分子质量分布随缩聚时间的变化关系,结果表明该反应为一逐步缩聚反应,缩聚速率随二酐电子亲和性(EA)的递增而增加;与预聚体聚酰胺酸相比,热处理环化得到聚酰亚胺其数均分子质量( Mn)和特性粘度[η]均有所下降,而分布指数(D)增大。此外还利用红外光谱(FTIR)、差分扫描量热法(DSC)、热重分析(TGA)等对聚酰亚胺进行了表征,结果表明聚酰亚胺(PI)的玻璃化温度(tg)和热分解温度(td)随着聚合单元长度的增加而降低。     

Synthesis and characterization of some aromatic polyimides

The diamine 2‐methyl‐1,3‐bis(4‐aminophenyloxy)benzene was prepared via a nucleophilic substitution reaction and was characterized with Fourier transform infrared, elemental analysis, and ¹H‐ and ¹³C‐NMR spectroscopy. The prepared diamine was also characterized with single‐crystal analysis. The geometric parameters of C₁₉H₁₈N₂O₂ were in the usual ranges. The dihedral angles between the central phenyl ring and the two terminal aromatic rings were 88.9 and 91.6°. The crystal structure was stabilized by N? H···N hydrogen bonds. The diamine was then polymerized with 3,3′,4,4′‐benzophenone tetracarboxylic acid dianhydride, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride, 3,4,9,10‐perylenetetracarboxylic acid dianhydride, and pyromellitic dianhydride by either a one‐step solution polymerization reaction or a two‐step procedure. These polymers had inherent viscosities ranging from 0.61 to 0.85 dL/gm. Some of the polymers were soluble in most common organic solvents even at room temperature, and some were soluble on heating. The degradation temperatures of the resultant polymers fell in the range of 260–500°C in nitrogen (with only 10% weight loss). The specific heat capacity at 200°C ranged from 1.0 to 2.21 J g^?1 K^?1. The temperatures at which the maximum degradation of the polymer occurred ranged from 510 to 610°C. The glass‐transition temperatures of the polyimides ranged from 182 to 191°C. The activation energy and enthalpy of the polyimides ranged from 44.44 to 73.91 kJ/mol and from 42.58 to 72.08 kJ/mol K, respectively. The moisture absorption was found in the range of 0.23–0.71%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis and characterization of 4,4'-diethylaminobenzil

以二苯乙二醇为原料,经氧化、还原、酰化、还原、硫酸铜-吡啶体系氧化5步反应得标题化合物.中间体及目标物的结构通过质谱、核磁共振氢谱和元素分析进行了表征,证明了该合成路线的可行性.     

BAMPM基高可溶高透光聚酰亚胺的制备及表征

将3,3',5,5'-四甲基-4,4'-二胺基苯基-4'-甲基甲苯(BAMPM)与均苯四甲酸二酐(PMDA)、联苯四甲酸二酐(BPDA)、联苯醚二酐(ODPA)、六氟二酐(6FDA)通过一步高温缩聚法制备了四种新型聚酰亚胺(PI)。所得聚酰亚胺在普通有机溶剂中具有优异的溶解性。聚酰亚胺的玻璃化转变温度(Tg)超过332℃,10%热失重温度为530～537℃。溶液浇铸法制备的聚酰亚胺薄膜具有高光学透明性,UV截止波长为312～366 nm,80%透过率波长为382～436 nm。该薄膜的拉伸强度为60.5～84.7 MPa,弹性模量为1.7～2.4 GPa,断裂伸长率为5.9%～10.2%。     

Synthesis and characterization of polyimides from divalent metal salts of p-aminobenzoic acid

Some 50 metal-containing polyimides with the metallic elements (Mg, Ca, Sr, Ba, Pb, Co, Ni) in the main chain were prepared first by reacting pyromellitic dianhydride (PMDA) with the mixture of divalent metal salts of p-aminobenzoic acid [ABA(M)] and 4, 4'-diaminodiphenylmethane (MDA) to form polyamic acid salts, and then the desired polyimides were obtained in high yield by separating the polyamic acid salts from the solvent and heating them under the imidization conditions. The structures of the samples were characterized by ¹H-NMR and IR, and the thermal properties of polyimides were measured by TG-DTA. It was found that the thermooxidative stability of polyimides decreased as a small amount of a metal element was introduced, and the stability of polymer varied slightly or tends to constancy as the metal content increased to a certain degree. In addition, the inherent viscosity of the polyamic acid salt solutions also decreased markedly with the increase of the metal content. © 1996 John Wiley & Sons, Inc.     

Synthesis and characterization of polyimides containing pyridine moiety

A series of new polyimides was prepared by reacting 2,6‐diaminopyridine with various aromatic dianhydrides in DMF in 1 : 1 mole ratio. All the resulting polyimides were readily soluble in organic solvents such as dimethylformamide, N,N‐dimethylacetamide, pyridine, m‐cresol, THF, etc. They also show good film‐forming ability. The polyimides exhibit good thermal stability and mechanical properties. The polymers have high T_g in the range of 252–296°C. The inherent viscosities of the polymers vary from 0.81 to 1.28 dL/g. A new class of bismaleimide and polyaspartimide as also synthesized. All the resulting polymer structures were characterized by FTIR and elemental analysis. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1846–1853, 2004     

Synthesis and characterization of formal-group-containing diisocyanates and polyimides therefrom

Four new formal-group-containing diisocyanates, namely, bis(3-isocyanatophenoxy) methane, bis(4-isocyanatophenoxy)methane, bis[2-(3-isocyanatophenoxy)ethyl] formal, and bis[2-(4-isocyanatophenoxy)ethyl] formal, were synthesized by the Curtius rearrangement from the corresponding dicarboxylic acids. The diisocyanates were polycondensed with pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylic dianhydride (BTDA) in dimethylacetamide (DMAc) to obtain formal-group-containing polyimides. These polyimides were characterized by viscosity measurements, IR spectroscopy, X-ray diffraction, and thermogravimetric analysis.     

Synthesis and characterization of fluorine and nitrile containing polyimides

A series of polyimides were synthesized from new diamine, Bis [4,4′‐amino‐5,5′ trifluoromethyl phenoxy‐(hexafluoro isopropylidine) phenoxy phenyl] benzonitrile [BATFB] and various aromatic tetracarboxylic anhydrides by thermal and chemical imidization routes. The BATFB was synthesized in two steps by nucleophilic displacement reaction of 2,6‐dichloro benzonitrile, 4,4′‐(hexafluoro isopropylidine) diphenol and 2‐amino‐5‐fluoro benzotrifluoride in the presence of anhydrous potassium carbonate in N,N′‐dimethyl acetamide (DMAc) and the structure was confirmed by FTIR spectroscopy and CHNSO analyzer. The polymers were characterized by FTIR spectroscopy and thermal analysis were performed by differential scanning calorimetry and thermogravimetric analysis methods. The prepared polyimides had glass transition temperatures between 230 and 290°C and their 10% weight loss were recorded in the range 550–590°C in N₂ atmosphere. Majority of polymers are found to be soluble in most of the organic solvents such as DMSO, DMF, DMAc, m‐cresol, and THF even at room temperature and few becomes soluble on heating. The prepared polyimides showed water uptake values 0.34–0.54 wt % at room temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3455–3461, 2006     

4,4'-二羟基二苯砜的合成及表征

本文以苯酚和98%浓H2SO4为原料,苯为除水剂合成了显色剂4,4'-二羟基二苯砜(BPS),并利用FTIR、XRD等分析手段对产品性能进行了表征.同时,探讨了反应物配比和反应温度等条件对BPS产率的影响.实验表明:在160℃反应条件下,H2SO4与苯酚摩尔比为0.6:1时,合成产物经精制后产率达86%.     

Synthesis and characterization of new water-soluble precursors of polyimides

We have successfully synthesized and characterized new water-soluble precursors of polyimides based on dianhydrides with diaminobenzene sodium sulfonate (DABSS) and diaminostilbene disodium sulfonate (DASBDSS). The precursors are soluble in water and methanol as well as in several aprotic solvents. The optimum inherent viscosities of the poly(amic acids), obtained by varying reaction temperatures, were measured using a conventional Ubbelohde viscometer. The average molar mass of the polymers expressed as the “poly(ethylene oxide)-PEO/poly(ethylene glycol)-PEG equivalent” molecular masses obtained by gel permeation chromatography (GPC) showed significant broad molecular mass distributions with their polydispersities ranging from 2.9 to 4.6. FT-IR spectra revealed complete imidization of the polyimides. Their thermal properties were studied by techniques such as differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Polyimides derived from the dianhydrides and DASBDSS showed better thermal stability up to 40°C in nitrogen than in oxygen atmosphere. However, polyimides based on the dianhydrides and DABSS were slightly more stable in oxygen than in nitrogen atmosphere. In oxygen, all the synthesized polyimides exhibited weight losses of about 50% in the range of 450–510°C. The overall weight losses of these polyimides under nitrogen were less than 50% at 700°C. New network polymellitimides based on mellitic trianhydride (MTA) and DABSS, and co-polymellitimides based on MTA, DABSS, and ODA (oxydianiline) were also synthesized and characterized successfully. Their thermal stabilities were compared with the linear polyimides using TGA and DSC.     

Aromatic polyimides from m‐phenylene diamines containing pendant groups: Synthesis and characterization

Two diamine monomers, 4‐[4‐(1‐methyl‐1‐phenylethyl)phenoxy]‐1,3‐diamino benzene and 4‐{4‐[(4‐methylphenyl)sulfonyl]phenoxy}‐1,3‐diamino benzene, were synthesized, and both diamines were polycondensed with three commercial dianhydrides to obtain aromatic polyimides containing pendant groups. The polyimides were characterized by solubility tests, viscosity measurements, IR, ¹H‐NMR, and ¹³C‐NMR spectroscopy, X‐ray diffraction studies, and thermogravimetric analysis. The polyimides had inherent viscosities of 0.33–0.58 dL/g in m‐cresol at 30 ± 0.1°C. All the polyimides were amorphous and were soluble in solvents such as N,N‐dimethylacetamide, N‐methyl‐2‐pyrrolidone, N,N‐dimethylformamide, and m‐cresol. Thermogravimetric analysis of the polyimides indicated no weight loss below 410°C under a nitrogen atmosphere. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1377–1384, 2005     

Aromatic polyimides: Synthesis,characterization, and evaluation of electric strength

Aromatic polyimides have been synthesized via the formation of polyamic acids in solution. This solution was cast into films that were thermally imidized. The imidization process was monitored using FTIR. The degree of imidization was also determined with thermo-gravimetric analysis. The electric breakdown field strength was tested under ac and dc conditions. Ac electric breakdown field strength measured in transformer oil was shown to follow a power-law dependence on film thickness. This dependence was not affected by the molecular mass of the polymer but changed with the degree of imidization and the electron-accepting properties of the diamine. High ac breakdown field values of polymides were obtained in dibutyl phthalate medium due to the suppression of partial discharges that occurs under these conditions. Measurements on films with thicknesses up to 60 μ showed no thickness dependence. No significant influence of the chemical structure on the break-down field strength was observed under these conditions. Breakdown field measurements under dc conditions showed high values, which were in good agreement with the peak values of the ac measurements in dibutyl phthalate. This indicates similarities in the intrinsic ac and dc breakdown processes. © 1993 John Wiley & Sons, Inc.     

Synthesis and characterization of polyimides and polyamide-imides containing azomethine linkages

Polyimides and polyamide-imides containing azomethine linkages in the polymer backbone have been synthesized from 4,4′-bis(4-isocyanatobenzylidene)-diaminodiphenylether (ODAI), 4,4′-bis(4-isocyanatobenzylidene)-diaminodiphenyl-methane (MADI), 4,4′-bis(4-isocyanatobenzylidene)-diaminodiphenylsulphone (SDAI), pyromellitic dianhydride (PMDA), 3,3′,4,4′-benzophenone tetracarboxylic dianhydride (BTDA), and trimellitic anhydride (TMA), by a one-step process. The diisocyanates ODAI, MDAI and SDAI were prepared from the corresponding diacids, namely, 4,4′-bis(4-carboxybenzylidene)-diaminodiphenylether (ODAA), 4,4′-bis(4-carboxybenzylidene)-diaminodiphenylmethane (MDAA) and 4,4′-bis-(4-carboxybenzylidene)-diaminodiphenylsulphone (SDAA) by a Weinstock-modified Curtius rearrangement method. All the polycondensation reactions were conducted in N-methyl-2-pyrrolidone (NMP) under identical conditions and the polymers obtained were characterized by IR spectroscopy, solution viscosity, elemental analysis, thermogravimetric analysis, differential scanning calorimetry and X-ray diffraction.     

polyimides containing s-triazine rings in the main chain: Synthesis and characterization

Eight s-triazine-containing polyimides were synthesized by solution polycondensation of diisocyanates having an s-triazine ring with pyromellitic dianhydride in dimethylacetamide. Polyimides derived from meta-oriented diisocyanates were amorphous and soluble in dipolar aprotic solvents while those based on para-oriented diisocyanates were semicrystalline and insoluble in organic solvents. However, all the polyimides were soluble in concentrated sulphuric acid. The polyimides showed similar patterns of decomposition with no weight loss below 300°C in air.     

4,4'-联苯二酚二缩水甘油醚的合成与表征

以4,4'-联苯二酚和环氧氯丙烷为原料两步法合成4,4'-联苯二酚二缩水甘油醚。讨论了催化体系、原料配比、碱用量对产物质量的影响,确定了最佳反应条件为:n(4,4'-联苯二酚)∶n(环氧氯丙烷)=1∶16;n(4,4'-联苯二酚)∶n(NaOH)=1∶3.0,并用红外光谱和核磁共振对产物结构进行表征,同时对产物的分子质量、环氧值、有机氯含量、无机氯含量、熔点进行测定。结果表明,它的分子质量为299.1,环氧值为0.65～0.67,有机氯<40mg/100g、无机氯<20mg/100g、熔程为159.1～160.4℃。