Synthesis and characterization of novel fluorinated polyimides derived from 4,4′-[2,2,2-trifluoro-1-(3,5-ditrifluoromethylphenyl)ethylidene]diphthalic anhydride and aromatic diamines

A novel fluorinated aromatic dianhydride, 4,4′-[2,2,2-trifluoro-1-(3,5-ditrifluoromethylphenyl) ethylidene] diphthalic anhydride (9FDA), was synthesized, which was employed to polycondense with various aromatic diamines, including 4,4′-oxydianiline, 1,4-bis(4-aminophenoxy) benzene, 3,4′-oxydianiline and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene to produce a series of fluorinated aromatic polyimides. The fluorinated polyimides obtained had inherent viscosities ranged of 0.61-1.14 dL/g and were easily dissolved both in polar aprotic solvents and in low boiling point common solvents. High quality polyimide films could be prepared by casting the polyimide solution on glass plate followed by thermal baking to remove the organic solvents and volatile completely. Experimental results indicated that the fluorinated polyimides exhibited good thermal stability with glass transition temperature ranged of 245-283 °C and temperature at 5% weight loss of 536-546 °C. Moreover, the polyimide films showed outstanding mechanical properties with the tensile strengths of 87.7-102.7 MPa and elongation at breaks of 5.0-7.8%, good dielectric properties with low dielectric constants of 2.71-2.97 and low dissipation factor in the range of 0.0013-0.0028.     

一种三元共聚型聚酰亚胺的制备与表征

以3,3'-二甲基-4,4'-二氨基二苯甲烷、1,3-双(4-氨基苯氧基)苯(1,3-APB)与3,3',4,4'-二苯醚四羧酸二酐(ODPA)进行缩聚反应,制得一种新型的三元共缩聚型聚酰亚胺。将此聚合物与两种二元共缩聚型聚酰亚胺的性能进行对此,发现三元共聚型聚酰亚胺的溶解性能、力学性能和热性能皆较好,且使用范围扩大。     

Gas transport properties of 6FDA-TAPOB hyperbranched polyimide membrane

Physical and gas transport properties of the hyperbranched polyimide prepared from a triamine, 1,3,5-tris(4-aminophenoxy)benzene (TAPOB), and a dianhydride, 4,4′-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), were investigated and compared with those of linear-type polyimides with similar chemical structures prepared from diamines, 1,4-bis(4-aminophenoxy)benzene (TPEQ) or 1,3-bis(4-aminophenoxy)benzene (TPER), and 6FDA. 6FDA-TAPOB hyperbranched polyimide exhibited a good thermal stability as well as linear-type analogues. Fractional free volume (FFV) value of 6FDA-TAPOB was higher than those of the linear-type analogues, indicating looser packing of molecular chains attributed to the characteristic hyperbranched structure. It was found that increased resistance to the segmental mobility decreases the gas diffusivity of 6FDA-TAPOB, in spite of the higher FFV value. However, 6FDA-TAPOB exhibited considerably high gas solubility, resulting in high gas permeability. It was suggested that low segmental mobility and unique size and distribution of free volume holes arising from the characteristic hyperbranched structure of 6FDA-TAPOB provide effective O₂/N₂ selectivity. It is concluded that the 6FDA-TAPOB hyperbranched polyimide has relatively high permeability and O₂/N₂ selectivity, and is expected to apply to a high-performance gas separation membrane.     

Organosoluble and light-colored fluorinated semialicyclic polyimide derived from 1,2,3,4-cyclobutanetetracarboxylic dianhydride

In this study, the alicyclic dianhydrides 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) was polymerized with seven kinds of fluorinated aromatic diamines, 2,2′-bis(trifluoromethyl)-4,4′-diaminobiphenyl (1), 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (2), 1,4-bis(4-amino-2-trifluoromethylphenoxy)diphenyl (3), 1,4-bis(4-amino-2-trifluoromethylphenoxy) diphenyl ether (4), 2,2-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]hexafluoropropane (5), 4,4′-bis(4-amino-2-trifluoromethylphenoxy)diphenyl sulfone (6), and 2,7-bis(4-amino-2-trifluoromethylphenoxy)naphthalene (7), via a two-step polycondensation procedure to prepare seven kinds of fluorinated semialicyclic polyimides (PI) PI-1 ∼ PI-7. The structures of these polyimides were confirmed by infrared spectroscopy (IR). Solubility of the polyimides was tested in various organic solvents and their thermal properties were investigated by dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). Ultraviolet-visible spectra (UV-vis) and near infrared absorption spectra (NIR) were obtained to evaluate the optical properties of these polyimides. The obtained polyimides PI-1 ∼ PI-7 displayed excellent solubility in a variety of organic solvents; they were readily soluble in amide-type polar solvent. These polyimide films exhibited good optical transparency in the visible light region (400–700 nm) with the transmittance higher than 80% at 450 nm, and these polyimide films showed little absorption at the optocommunication wavelengths of 1.30 and 1.55 μm. These polyimides showed good thermal stability with the 10% thermal decomposing temperatures higher than 443°C in nitrogen and the glass transition temperatures higher than 265°C. In addition, the effect of the structure of fluorinated diamines on the properties of polyimide films was also compared. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Novel organosoluble fluorinated polyimides derived from 1,6-bis(4-amino-2-trifluoromethylphenoxy)naphthalene and aromatic dianhydrides

A novel trifluoromethyl-substituted bis(ether amine) monomer, 1,6-bis(4-amino-2-trifluoromethylphenoxy)naphthalene, was prepared through the nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride and 1,6-dihydroxynaphthalene in the presence of potassium carbonate in dimethyl sulfoxide, followed by catalytic reduction with hydrazine and Pd/C in ethanol. A series of new fluorinated polyimides were synthesized from the diamine with various commercially available aromatic tetracarboxylic dianhydrides via a conventional two-stage process with the thermal or chemical imidization of the poly(amic acid) precursors. Most of the polyimides obtained from both routes were soluble in many organic solvents such as N-methyl-2-pyrrolidone and N,N-dimethylacetamide. All the polyimides could afford transparent, flexible, and strong films with low moisture absorptions of 0.12–0.52% and low dielectric constants of 2.75–3.13 at 10 kHz. Thin films of these polyimides showed an UV–vis absorption cutoff wavelength at 376–428 nm, and those of polyimides from 4,4′-oxydiphthalic dianhydride (ODPA) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) were essentially colorless. The polyimides exhibited excellent thermal stability, with decomposition temperatures (at 10% weight loss) above 530 °C in both air and nitrogen atmospheres and glass transition temperatures (T_gs) in the range of 241–298 °C. For a comparative study, some properties of the present fluorinated polyimides were compared with those of structurally related ones prepared from 1,6-bis(4-aminophenoxy)naphthalene and 2,6-bis(4-amino-2-trifluoromethylphenoxy)naphthalene.     

Heat stable and organosoluble polyimides containing laterally-attached phenoxy phenylene groups

In this research a diamine monomer containing two phenoxy phenylene lateral groups, 2,2′-bis[(p-phenoxy phenyl)]-4,4′-diaminodiphenyl ether (PPAPE) was used to prepare novel wholly aromatic polyimides by thermal or chemical two-step polycondensation reactions. Comonomers including pyromellitic dianhydride (PMDA), 4,4′-oxydiphthalic anhydride (ODPA), and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) were used for the polyimidization reactions. A reference polyimide was also prepared by the reaction of 4,4′-diaminodiphenyl ether (DADPE) with pyromellitic dianhydride (PMDA). The limited viscosity numbers as well as [`(M)]<sub>n</sub> \overline{M}_n and [`(M)]_w \overline{M}_w values of the resulting polymers were determined. All PPAPE-resulted polyimides had excellent organosolubility in common polar solvents. A low crystallinity extent was only observed using their wide-angle X-ray diffractograms (WAXD). The prepared hinged polyimides could also be cast into transparent and flexible films. The glass transition temperatures of the resulting polyimides were determined by differential scanning calorimetry (DSC) analyses. The thermograms obtained from thermogravimetric analyses (TGA) showed that the phenoxy phenylene lateral groups attached to the macromolecular backbones had no substantial diminishing effect on the thermal stability of these structurally-modified polyimides.     

均苯型共聚聚酰亚胺薄膜的制备及其性能

以2,2′-双[3-苯基-4(4-氨基苯氧基)苯基]丙烷(BPAPOPP)、4,4′-二胺基二苯醚和均苯四甲酸酐为原料,采用两步法共缩聚制备了一系列共聚聚酰亚胺薄膜.采用红外光谱仪、差示扫描量热仪等分析了薄膜的结构,利用静态热机械分析仪分析了薄膜的性能.结果表明:制备的聚酰亚胺薄膜具有较低的玻璃化转变温度;随着BPAP...     

以BAPP为原料的热塑性PI薄膜的合成及性能

以芳香长链二胺2,2-双[4-(4-氨基苯氧基)苯基]丙烷(BAPP)为二胺原料,与最具商业价值的四种酸酐均苯四甲酸二酐(PMDA)、3,3′,4,4′-联苯四酸二酐(BPDA)、3,3′,4,4′-二苯酮四酸二酐(BTDA)、3,3′,4．4′-二苯醚四酸二酐(ODPA)为二酸酐原料,采用二步溶液缩聚法制得了一系列均聚和共聚聚酰亚胺薄膜。利用FTIR表征了聚酰亚胺的结构,并用DSC、TOA、TMA DMA等手段测得了不同聚酰亚胺的Tg、5%与10%热失重温度、线膨胀系数、拉伸强度、断裂延伸率、热压粘接T型剥离强度等性能数据。     

Preparation and characterization of organosoluble polyimides based on 1,1-bis[4-(3,4-aminophenoxy)phenyl]cyclohexane and commercial aromatic dianhydrides

A bis(ether amine) III-A containing a cyclohexane cardo group, 1,1-bis[4-(4-aminophenoxy)phenyl]cyclohexane, was synthesized and used as a monomer to prepare polyimides VI-A with six commercial dianhydrides via three different procedures. The intermediate poly(amic acid)s had inherent viscosities of 0.83–1.69 dL g⁻¹ and were thermally or chemically converted into polyimides. Polyimides were also prepared by high-temperature direct polymerization in m-cresol and had inherent viscosities higher than the thermally or chemically cyclodehydrated ones. To improve the solubility of polyimides, six copolyimides were also synthesized from bis(ether amine) III-A with a pair of dianhydrides, which contained 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride or 4,4′-hexafluoroisopropylidenediphthalic anhydride. Series VI-A polyimides were characterized by the good physical properties of their film-forming ability, thermal stability, and tensile properties. A comparative study of the properties, with the corresponding polyimides derived from 2,2-bis[4-(4-aminophenoxy)phenyl]propane, is also presented. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2750–2759, 2001     

Synthesis of a new diamine and its effect on the residual stress of colorless polyimide

A new diamine was designed and synthesized to improve the flexibility of colorless polyimides by reducing residual stress. Four variations of colorless polyimides with the same dianhydride (4,4′-(hexafluoroisopropylidene)-diphthalic) and four different diamines (bis[4-(3-aminophenoxy)-phenyl] sulfone, bis(3-aminophenyl) sulfone, 2,2′-bis(trifluoromethyl)benzidine, and 2,2-bis(4-aminophenyl)-hexafluoropropane) were used. A series of colorless polyimides were prepared by adding the new diamine. The carbon and ether bonds between the benzene rings of the new diamine affected the flexibility and optical properties of colorless polyimide. The synthesis of the new diamine was confirmed by NMR measurements. Furthermore, the decrease in residual stress at room temperature and the glass transition temperature was confirmed. The effect of the new diamine was most evident for polyimide with a bulky and rigid structure. Though a slight yellow color appears because of the broken charge transfer complex balance, controlling the content of the new diamine will allow application of polyimides in flexible display.     

双烯丙基双酚A改性内扩链双马来酰亚胺研究

采用自制的叔丁基二胺单体1,4-双(4-氨基苯氧基)-2-叔丁基苯(BATB)与双酚A二酐(BPADA)反应,并以马来酸酐作为封端剂得到了一系列链中含酰亚胺环的内扩链双马来酰亚胺,将所得双马来酰亚胺混合双烯丙基双酚A(BBA)制得无胶型挠性覆铜板。采用傅里叶变换红外光谱(FTIR)、核磁共振氢谱(1H-NMR)、凝胶渗透色谱(GPC)、示差扫描量热法(DSC)和热重分析(TGA)对合成的封端聚酰亚胺树脂的结构进行了表征并测试了其性能,研究了BBA用量及加入前后对封端聚酰亚胺基膜力学性能、热性能、聚酰亚胺树脂固化性能的影响。结果表明,BBA与封端聚酰亚胺物质的量比为1∶1时,其增韧改性效果最佳。加入BBA后的薄膜在不降低热性能的情况下,力学性能提高(拉伸强度可达到67.14 MPa,弹性模量达到1 449.73 MPa,断裂伸长率最大达到6.17%)。所得两层型挠性覆铜板具有优异的耐热性、尺寸稳定性、低吸水率。     

Polyimides from 2,3,3′,4′-biphenyltetracarboxylic dianhydride and aromatic diamines

A series of new polyimides were prepared from the reaction of 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA) with various aromatic diamines. The properties of the a-BPDA polyimides were compared with those of polyimides prepared from the reaction of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA) with the same aromatic diamines. Films of the a-BPDA polyimides had higher glass transition temperatures (T_gs) and less color than the corresponding s-BPDA polyimide films. Light transmission at 500 nm, solar absorptivity, and thermal emissivity were determined on certain films. Films of similar polyimides based upon a-BPDA and s-BPDA containing meta linkages and others containing para linkages were each cured at 250, 300, and 350 °C. The films were characterized primarily by T_g, color, optical transparency, tensile properties, dynamic mechanical thermal analysis, and coefficient of thermal expansion. The a-BPDA meta linked polyimide films had tensile strengths and moduli higher than films of the a-BPDA para linked polyimide. The same phenomenon was not observed for the s-BPDA meta and para linked polyimides. The chemistry, mechanical, and physical properties of the polymers and films are discussed.     

Synthesis and properties of polyimides derived from cis- and trans-1,2,3,4-cyclohexanetetracarboxylic dianhydrides

Cis-1,2,3,4-cyclohexanetetracarboxylic dianhydride (cis-1,2,3,4-CHDA) was synthesized. It was found that under such conditions as heating or boiling in acetic anhydride, cis-1,2,3,4-CHDA could be converted to its trans-isomer. The process of thermal isomerization was monitored by ¹H NMR spectra and the mechanism of conversion was proposed. Their absolute structures of cis- and trans-1,2,3,4-CHDAs were elucidated by single crystal X-ray diffraction. The polycondensations of cis- and trans-1,2,3,4-CHDAs with aromatic diamines such as 4,4′-oxydianiline (ODA), 4,4′-methylenedianiline (MDA), 4,4′-diamino-3,3′-dimethyldiphenylmethane (DMMDA), 4,4′-bis(4-aminophenoxy)benzene (TPEQ), 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP) were studied. It is easy to obtain higher molecular weight polyimides from trans-1,2,3,4-CHDA using conventional one-step or two-step methods. However, higher molecular weight polyimides derived from cis-1,2,3,4-CHDA could not be prepared by the usual methods (solid content ca. 10%) owing to the trend of forming cyclic oligomers. Increasing the concentration of monomers could give higher molecular weight cis-polymers. All of the cis-polyimides were soluble at room temperature in aprotic polar solvents and phenolic solvents and some of them even soluble in chloroform and tetrahydrofuran, while the corresponding trans-polymers showed poor solubility as compared to cis-polymers. All of the polyimides showed good thermal stability with the 5% weight loss temperatures in air over 415 °C. Furthermore, polyimides derived from cis-1,2,3,4-CHDA have higher glass transition temperatures (T_gs) than corresponding trans-polyimides. The flexible polyimide films possessed a tensile modulus range of 2.1-3.6 GPa, a tensile strength range of 42-116 MPa, an elongation at break of 4-18%. These polyimides exhibited cutoffs at wavelengths around 270 nm and were entirely colorless. All the polyimides showed amorphous pattern according to Wide angle X-ray diffraction measurements. The differences of polymerization and properties were explained by the structural changes resulted from isomerism.     

Nanoscale blending of aliphatic and aromatic polyimides: A clue for forming semi-molecular composites and in-situ generation of copolyimide fractions

Summary Nanoscale blending of aromatic and aliphatic polyimides has been attempted by employing corresponding poly(amic acid) precursors in order to elucidate clues for achieving a semi-molecular composite film. Pyromellitic dianhydride (PMDA) and 4,4’-oxydianiline (ODA) were used to make the precursor polymer of aromatic polyimide (PMDA-ODA PI) as a semi-rigid rod-like component, whilst bicyclo[2,2,2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride (BOCA) and 4,4’-methylenebis(cyclohexylamine) (MCA) were used to prepare the precursor of aliphatic polyimide (BOCA-MCA PI) as a flexible coil-like component. The weight ratio of aromatic to aliphatic polyimides was varied from 100:0: to 0:100 by 10 wt % gap for monitoring the critical composition upon nanostructure changes. The micro/nanostructure of composite films was characterized by using small-angle X-ray scattering (SAXS) and X-ray diffraction (XRD), while the evolution and thermal property of semi-molecular composites were studied by using FT-IR spectroscopy and dynamic mechanical thermal analysis (DMTA). The result showed that the composite films exhibited a single glass transition behavior, which is ascribed to the molecular level mixing, in the presence of copolyimide fractions.     

Low-dielectric-constant aromatic homopolyimide and copolyimide derived from pyromellitic dianhydride, 4,4′-oxydianiline, 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene,or 1,3-bis(4-aminophenoxy)benzene

Low-dielectric-constant aromatics, homopolyimide and copolyimide, were introduced. Homopolyimides were prepared by pyromellitic dianhydride (PMDA) as an anhydride monomer and 4,4′-oxydianiline (ODA), 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene as an amine monomer. The copolyimides were prepared with PMDA as an anhydride monomer, ODA as an amine monomer with the addition of 2,2-bis[4-(4-aminephenoxy)phenyl]propane, 1,4-bis(4-aminophenoxy)benzene, or 1,3-bis(4-aminophenoxy)benzene as another amine monomer. The polyimides were well characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, thermomechanical analysis, dielectric measurements, and tensile testing. The homopolyimide and copolyimides showed lower dielectric constants than the homopolyimide formed by ODA and PMDA. The results also indicate that the interchain distance, the quantities of phenyl ether, and the position of the substitute are factors that not only affected the thermal performance of polyimide by improving the molecular flexibility but also reduced the dielectric constant of polyimide by increasing the free volume of the molecular chain and decreasing the polarization points per unit volume. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47405.     

High thermal stable thermoplastic-thermosetting polyimide film by use of asymmetric dianhydride (a-BPDA)

In order to obtain thermoplastic (before curing) and thermosetting (after curing) polyimides with high T_g for adhesive film, we prepared novel polyimides having phenylethynyl group in the side chain (44% of concentration of curing group) from asymmetric 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA), 3,4′-oxydianiline (3,4′-ODA) or 1,3-bis(4-aminophenoxy)benzene (1,3,4-APB) or 1,3-bis(3-aminophenoxy)benzene (1,3,3-APB), and 2,4-diamino-1-(4-phenylethynylphenoxy)benzene (mPDAp). Among three kinds of polymer, uncured polyimide of a-BPDA/1,3,4-APB; mPDAp had rather high T_g (265 °C, DMA) and thermoplasticity (E′ drop>10³ at T_g). After curing reaction of phenylethynyl group, the T_g of the polyimide was increased dramatically (364 °C, DMA). The polyimide derived from 1,3,4-APB having less concentration of curing group (20%) was also prepared to improve further film flexibility and toughness.     

Synthesis and characterization of novel polyimides derived from 2,6-bis[4-(3,4-dicarboxyphenoxy)benzoyl]pyridine dianhydride and aromatic diamines

A novel pyridine-containing aromatic dianhydride monomer, 2,6-bis[4-(3,4-dicarboxyphenoxy)benzoyl]pyridine dianhydride, was synthesized from the nitro displacement of 4-nitrophthalonitrile by the phenoxide ion of 2,6-bis(4-hydroxybenzoyl)pyridine, followed by acidic hydrolysis of the intermediate tetranitrile and cyclodehydration of the resulting tetraacid. A series of new polyimides holding pyridine moieties in main chain were prepared from the resulting dianhydride monomer with various aromatic diamines via a conventional two-stage process, i.e. ring-opening polycondensation forming the poly(amic acid)s and further thermal or chemical imidization forming polyimides. The inherent viscosities of the resulting polyimides were in the range of 0.51-0.68 dL/g, and most of them were soluble in aprotic amide solvents and cresols, such as N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and m-cresol, etc. Meanwhile, some strong and flexible polyimide films were obtained, which have good thermal stability with the glass transition temperatures of 221-278 °C, the temperature at 5% weight loss of 512-540 °C, and the residue at 800 °C of 60.4-65.3% in nitrogen, as well as have outstanding mechanical properties with the tensile strengths of 72.8-104.4 MPa and elongations at breakage of 9.1-11.7%. The polyimides also were found to possess low dielectric constants.     

化学亚胺化合成含吡啶环共聚聚酰亚胺

用2,2-双[4-（4-氨基苯氧基）苯基]丙烷（BAPP）和4-苯基-2,6-双（4．氨基苯基）吡啶（PBAP）作为二胺,3,3’,4,4＇-二苯酮四酸二酐（BTDA）作为二酐,以N,N-二甲基甲酰胺（DMF）为溶剂,合成了3种聚酰亚胺。先用BAPP和PBAP同BTDA反应生成一系列聚酰胺酸（PAA）,然后将得到的PAA用化学亚胺化制备相应的聚酰亚胺。用FT-IR、^1H—NMR、粘度测试、溶解性测试和TGA对聚合物的结构和性能进行了表征。结果表明,FT—IR测试在1780cm^-1、1720cm^-1和725cm^-1左右出现了聚酰亚胺的特征吸收峰,所得聚酰胺酸的特性粘数为0．32～0．46dL／g,大部分聚酰亚胺在常见有机溶剂NMP中可溶,它们有很好的热稳定性,氮气氛中,在500℃以前没有明显的降解。     

Study on preparation and properties of novel reactive phenolic hydroxyl-containing polyimides

Novel reactive polyimides (PIs) containing phenolic hydroxyl functionalities were prepared from 4-(4-hydroxyphenyl)-2,6-bis[3-(4-aminophenoxy)phenyl]pyridine (m,p-HAPP) with various aromatic dianhydrides via one-step polycondensation procedure. The inherent viscosities of the PIs were 0.54–0.63 dL/g in DMF solution and most of them were readily soluble in common organic solvents such as DMF, DMAc, NMP, and m-Cresol, etc. Meanwhile, the PIs also had good thermal stability, with the glass transition temperature (T _g) of 221.7–310.5 °C, the temperature at 10 % weight loss of 524.1–579.3 °C in nitrogen atmosphere. Then commercial epoxy resin was cured in the presence of different ratios of the reactive polyimide, giving a series of polyimide modified epoxy films. Thermogravimetric analysis showed the increase of the temperature at 5 % weight loss of the films with the increase of the polyimide content; 296 °C for 0 %, 309 °C for 1.95 %, 337 °C for 3.85 % and 350 °C for 5.63 %.     

含苯环侧基三元共聚PI的合成及其表征

以4,4’-二胺基二苯醚(ODA)、2,2’-双[3-苯基-4(4-氨基苯氧基)苯基]丙烷(BPAPOPP)和均苯四甲酸酐(PMDA)为单体,采用溶液共缩聚方法合成了一系列共聚聚酰亚胺(PI)薄膜;采用傅里叶红外光谱仪(FTIR)、差示扫描量热仪(DSC)等分析了PI薄膜的结构和性能。结果表明:随着高聚物中柔性体系含量的增加,PI薄膜的热学性能和力学性能都有一定程度降低;但其加工性能得到了改善。