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1.
Andrew E. Feiring Edward R. Wonchoba Samuel D. Arthur 《Journal of polymer science. Part A, Polymer chemistry》1990,28(10):2809-2819
New fluorinated poly(ether sulfone)s were prepared from bisphenols and α,ωbis(4-fluorophenylsulfonyl)perfluoroalkanes. The fluorinated sulfone monomers were synthesized by reaction of 4-fluorobenzenethiol salts with perfluoroalkylene diiodides, followed by oxidation. Sodium carbonate mediated polymerization gave high molecular weight polymers in excellent yield. The polymers are generally soluble in chlorinated hydrocarbons and some dipolar solvents, are amorphous with Tg's in the range of 120–160°C and are stable to 400°C. They form clear, colorless films by solution casting. Cast films have dielectric constants and dissipation factors somewhat below those of typical poly(ether sulfone)s, and show good permeability and selectivity for O2/N2 gas separations. 相似文献
2.
New fluorinated polyamides were prepared directly from a diamine, 9,9‐bis[4‐(2‐trifluoromethyl‐4‐aminophenoxy)phenyl]xanthene ( BTFAPX ) with various aromatic dicarboxylic acid chlorides by low‐temperature polycondensation. The polymers were produced with moderate‐to‐high inherent viscosities of 0.65–1.01 dl/g while the weight‐average molecular weight and number‐average molecular weight were in the range of 69,000–82,000 and 39,000–43,000, respectively. Nearly all the polymers were readily soluble in amide‐type polar aprotic solvents [e.g. N, N‐dimethylacetamide (DMAc) and N‐methyl‐2‐pyrrolidinone], and even in less polar solvents such as dimethyl sulfoxide and pyridine, and afforded transparent, light‐colored, and flexible films upon casting from DMAc solvent. The polymers showed glass transition temperatures between 235 and 284°C, and 10% weight loss temperatures ranging from 495 to 532°C and 476 to 510°C in nitrogen and air, respectively, and char yields higher than 55% at 800°C in nitrogen. All polymers were amorphous and their films exhibited tensile strengths of 64–95 MPa, elongations at break of 6–9%, and tensile moduli of 1.9–2.5 GPa. These polymers had dielectric constants ranging from 3.65 to 4.03 (100 Hz), low‐moisture absorption in the range of 0.56–1.14%, and high transparency with an ultraviolet–visible absorption cut‐off wavelength in the 334–372 nm range. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
3.
Chin‐Ping Yang Yu‐Yang Su 《Journal of polymer science. Part A, Polymer chemistry》2006,44(9):3140-3152
A novel series of colorless and highly organosoluble poly(ether imide)s were prepared from 3,3‐bis[4‐(3,4‐dicarboxyphenoxy)phenyl]phthalide dianhydride with various fluorinated aromatic bis(ether amine)s via a conventional two‐stage process that included ring‐opening polyaddition to form the poly(amic acid)s followed by cyclodehydration to produce the polymer films. The poly(ether imide)s showed excellent solubility, with most of them dissoluble at a concentration of 10 wt % in amide polar solvents, in ether‐type solvents, and even in chlorinated solvents. Their films had a cutoff wavelength between 358 and 373 nm, and the yellowness index ranged from 3.1 to 9.5. The glass‐transition temperatures of the poly(ether imide) series were recorded between 237 and 297 °C, the decomposition temperatures at 10% weight loss were all above 494 °C, and the residue was more than 54% at 800 °C in nitrogen. These films showed high tensile strength and also were characterized by higher solubility, lighter color, and lower dielectric constants and moisture absorption than an analogous nonfluorinated polyimide series. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3140–3152, 2006 相似文献
4.
Yu Shao Yan‐Feng Li Xin Zhao Xiao‐Long Wang Tao Ma Feng‐Chun Yang 《Journal of polymer science. Part A, Polymer chemistry》2006,44(23):6836-6846
A new aromatic, unsymmetrical ether diamine with a trifluoromethyl pendent group, 1,4‐(2′‐trifluoromethyl‐4′,4″‐diaminodiphenoxy)benzene, was successfully synthesized in three steps with hydroquinone as a starting material and polymerized with various aromatic tetracarboxylic acid dianhydrides, including 4,4′‐oxydiphthalic anhydride, 3,3′,4,4′‐benzophenone tetracarboxylic dianhydride, 2,2′‐bis(3,4‐dicarboxyphenyl)‐hexafluoropropane dianhydride, and pyromellitic dianhydride, via a conventional two‐step thermal or chemical imidization method to produce a series of fluorinated polyimides. The polyimides were characterized with solubility tests, viscosity measurements, IR, 1H NMR, and 13C NMR spectroscopy, X‐ray diffraction studies, and thermogravimetric analysis. The polyimides had inherent viscosities of 0.56–0.77 dL/g and were easily dissolved in both polar, aprotic solvents and common, low‐boiling‐point solvents. The resulting strong and flexible polyimide films exhibited excellent thermal stability, with decomposition temperatures (at 5% weight loss) above 522 °C and glass‐transition temperatures in the range of 232–272 °C. Moreover, the polymer films showed outstanding mechanical properties, with tensile strengths of 74.5–121.7 MPa, elongations at break of 6–13%, and initial moduli of 1.46–1.95 GPa, and good dielectric properties, with low dielectric constants of 1.82–2.53 at 10 MHz. Wide‐angle X‐ray diffraction measurements revealed that these polyimides were predominantly amorphous. These outstanding combined features ensure that the polymers are desirable candidate materials for advanced microelectronic applications. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6836–6846, 2006 相似文献
5.
Jong‐Woon Ha Yuntae Kim Jeongkyun Roh Fei Xu Jong Il Park Jeonghun Kwak Changhee Lee Do‐Hoon Hwang 《Journal of polymer science. Part A, Polymer chemistry》2014,52(22):3260-3268
New low‐temperature curable organic/inorganic hybrid polymers were designed and synthesized as gate dielectrics for organic thin‐film transistors (OTFTs). Allyl alcohols were introduced to polyhedral oligomeric silsesquioxane (POSS) via hydrosilyation to produce an alcohol‐functionalized POSS derivative (POSS‐OH). POSS‐OH was then reacted with hexamethoxymethylmelamine at carrying molar ratios at 80 °C in the presence of a catalytic amount of p‐toluenesulfonic acid to give highly cross‐linked network polymers (POSS‐MM). The prepared thin films were smooth and hard after the thermal cross‐linking reaction and had very low leakage currents (<10?8 A/cm2) with no significant absorption over the visible spectral range. Pentacene‐based OTFTs using the synthesized insulators as gate dielectric layers had higher hole mobilities (up to 0.36 cm2/Vs) than a device using thermally cross‐linked poly(vinyl phenol) and melamine as the gate dielectric layer (0.18 cm2/Vs). © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3260–3268 相似文献
6.
New fluorinated aromatic poly (ether ketone amide)s containing cardo structures were prepared by a heterogeneous palladium‐catalyzed polycondensation of fluorinated aromatic diiodides with ether ketone units, aromatic diamines containing cardo groups, and CO. Polymerizations were conducted in N,N‐dimethylacetamide at 120°C using 6 mol% of magnetic nanoparticles‐supported bidentate phosphine palladium (II) complex [Fe3O4@SiO2‐2P‐PdCl2] as catalyst and 1,8‐diazabicyclo[5,4,0]‐7‐undecene as base and resulted in fluorinated cardo poly (ether ketone amide)s with inherent viscosities up to 0.75 dL/g. All the polymers were readily soluble in many organic solvents and could afford transparent, flexible, and strong films by solution casting. These polymers showed good thermal stability with the glass transition temperature of 237°C–258°C, the temperature at 5% weight loss of 462°C–477°C in nitrogen. These polymer films also exhibited good mechanical properties, excellent electrical and dielectric performance, and high optical transparency. The incorporation of bulky fluorinated groups and cardo structures into polymer backbone has played an important role in the improvement of solubility, dielectric performance, and optical properties. Importantly, the heterogeneous palladium catalyst can easily be recovered from the reaction mixture by simply applying an external magnet and recycled up to 7 times without significant loss of catalytic activity. 相似文献
7.
Susanta Banerjee Mukesh Kumar Madhra Arun Kashinath Salunke Gerhard Maier 《Journal of polymer science. Part A, Polymer chemistry》2002,40(8):1016-1027
A new diamine monomer, 4,4″‐bis(aminophenoxy)‐3,3″‐trifluoromethyl terphenyl (ATFT) was synthesized that led to a number of novel fluorinated polyimides by solution as well as thermal imidization routes when reacted with different commercially available dianhydrides like pyromellatic dianhydride (PMDA), benzophenone tetracarboxylic acid dianhydride (BTDA), or 2,2‐bis(3,4‐dicarboxyphenyl) hexafluoropropane (6FDA). The polyimides ATFT/BTDA and ATFT/6FDA derived from both routes were soluble in several organic solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, and dimethyl sulfoxide. The polyimide ATFT/PMDA was only soluble in N‐methylpyrollidone. The polyimide films had low water absorption of 0.3–0.7%, low dielectric constants of 2.72–3.3 at 1 Hz, refractive indices of 1.594–1.647 at 589.3 nm, and optical transparency >85%. These polyimides showed very high thermal stability with decomposition temperatures (5% weight loss) up to 532 °C in air and good isothermal stability; only 7% weight loss occurred at 400 °C after 7 h, and less than 0.6% weight loss was observed at 315 °C for 5 h. Transparent thin films of these polyimides exhibited tensile strengths up to 112 MPa, a modulus of elasticity up to 3.05 GPa, and elongation at break up to 21% depending on the repeating unit structure. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1016–1027, 2002 相似文献
8.
S. Y. Yang Z. Y. Ge D. X. Yin J. G. Liu Y. F. Li L. Fan 《Journal of polymer science. Part A, Polymer chemistry》2004,42(17):4143-4152
A novel fluorinated aromatic dianhydride, 4,4′‐[2,2,2‐trifluoro‐1‐(3‐trifluoromethyl‐phenyl)ethylidene]diphthalic anhydride (TFDA) was synthesized by coupling of 3′‐trifluoromethyl‐2,2,2‐trifluoroacetophenone with o‐xylene under the catalysis of trifluoromethanesulfonic acid, followed by oxidation of KMnO4 and dehydration. A series of fluorinated aromatic polyimides derived from the novel fluorinated aromatic dianhydride TFDA with various aromatic diamines, such as p‐phenylenediamine (p‐PDA), 4,4′‐oxydianiline (ODA), 1,4‐bis(4‐aminophenoxy)benzene (p‐APB), 1,3‐bis(4‐amino‐phenoxy)benzene (m‐APB), 4‐(4‐aminophenoxy)‐3‐trifluoromethylphenylamine (3FODA) and 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene (6FAPB), were prepared by polycondensation procedure. All the fluorinated polyimides were soluble in many polar organic solvents such as NMP, DMAc, DMF, and m‐cresol, as well as some of low boiling point organic solvents such as CHCl3, THF, and acetone. Homogeneous and stable polyimide solutions with solid content as high as 35–40 wt % could be achieved, which were prepared by strong and flexible polyimide films or coatings. The polymer films have good thermal stability with the glass transition temperature of 232–322 °C, the temperature at 5% weight loss of 500–530 °C in nitrogen, and have outstanding mechanical properties with the tensile strengths of 80.5–133.2 MPa as well as elongations at breakage of 7.1–12.6%. It was also found that the polyimide films derived from TFDA and fluorinated aromatic diamines possess low dielectric constants of 2.75–3.02, a low dissipation factor in the range of 1.27–4.50 × 10?3, and low moisture absorptions <1.3%. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4143–4152, 2004 相似文献
9.
Chin‐Ping Yang Yu‐Yang Su Kuen‐Lin Wu 《Journal of polymer science. Part A, Polymer chemistry》2004,42(21):5424-5438
A novel, fluorinated diamine monomer, 2,5‐bis(4‐amino‐2‐ trifluoromethylphenoxy)‐tert‐butylbenzene ( II ) was synthesized through the nucleophilic substitution reaction of tert‐butylhydroquinone (t‐BHQ) and 2‐chloro‐5‐nitrobenzotrifluoride in the presence of potassium carbonate to yield the intermediate dinitro compound I , followed by catalytic reduction with hydrazine and Pd/C to afford diamine II . A series of fluorinated polyimides V were prepared from II with various aromatic dianhydrides ( III a–f ) via the thermal imidization of poly(amic acid). Most of V a–f could be soluble in amide‐type solvents and even in less polar solvents. These polyimide films showed tensile strengths up to 106 MPa, elongation at break up to 21%, and initial modulus up to 2.1 GPa. The glass‐transition temperature of V was recorded at 245–304 °C, the 10% weight loss temperatures were above 488 °C, and left more than 41% residue even at 800 °C in nitrogen. Low dielectric constants, low moisture absorptions, and higher and light‐colored transmittances were also observed. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5424–5438, 2004 相似文献
10.
As the demand for downsizing in microelectronics is increasing, devices require material with lower dielectric constant accordingly. The dielectric constants for most polyimide (PI), including polyetherimide (PEI), films are ∼3.5. In this study, we modified the PEI by incorporating various monomers (fluorinated dianhydride 6FDA and phenylene ether diamines) to reduce the dielectric constant. The dielectric constants of synthesized PEIs decreased with increasing amounts of 6FDA content and phenylene ether units. The Tg decreased gradually with PEI containing longer phenylene ether units, but increased with the content of 6FDA. The thermal decomposition temperatures at 10% weight loss were ∼550 °C, indicating that these PEIs have high thermal stability. Both the tensile strength and the modulus decreased with the PEI containing longer phenylene ether units. The PEI synthesized with 40% 6FDA dianhydride and 1,4-bis(4-aminophenoxy)benzene (pBAB) diamine has the lowest dielectric constant of 2.78 at 1 MHz. 相似文献
11.
Block and random polyhedral oligomeric silsesquioxane (POSS)/fluorinated poly aryl ether sulfone tricopolymers were synthesized using different synthetic strategies to investigate the effect of sequence distribution on their thermal, dielectric, and surface properties. Analyses indicated that all block and random copolymers showed similar growth tendency of water contact angles and Tg values, downward tendency of k values with increased content of POSS. The block copolymer displayed higher Tg values up to 187°C than random copolymers (173°C) under the same POSS molar percentage, which were highly related to their different sequence distribution. The dielectric constants of the tricopolymers were drastically reduced because of the presence of POSS and fluorine, and the dielectric constant could achieve as low as 2.71 (1 MHz). Besides, sequence distribution has no obvious influence on its surface properties and properties. Meanwhile, the yields of degradation residues of the tricopolymers were significantly improved by the ceramic formation from POSS moieties during thermal decomposition. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
12.
A new unsymmetrical and noncoplanar diamine containing trifluoromethyl and trimethyl groups, 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐2,3,5‐trimethylbenzene ( 2 ), was synthesized using 2,3,5‐trimethylhydroquinone and 2‐chloro‐5‐nitrobenzotrifluoride as starting materials. A series of fluorinated poly(ether imide)s (PEIs) ( 4a–4d ) were prepared from diamine 2 with four aromatic dianhydrides via a one‐step high‐temperature polycondensation procedure. The obtained PEIs were readily soluble in most organic solvents and could be solution‐cast into flexible and strong films. The resulting thin films exhibited light color and good optical transparency with a cutoff wavelength of 356–376 nm. They also displayed good thermal stability with glass transition temperatures (Tg) above 281°C, 10% weight loss temperatures in the range of 482–486°C, and the weight residue more than 55% at 800°C in nitrogen. Moreover, they revealed low dielectric constants (2.77–2.93 at 1 MHz) and low moisture absorptions (0.41%–0.57%). 相似文献
13.
A novel, fluorinated diamine monomer with the ether–ketone group, 4,4′‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzophenone ( 2 ), was prepared through the nucleophilic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 4,4′‐dihydroxybenzophenone in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. Flourinated polyimides (PIs) 5a – f and copolyimides (co‐PIs) 5c / a – f were synthesized from 2 and various commercial aromatic dianhydrides via thermal or chemical imidization. PIs 5a – f had inherent viscosities ranging from 0.72 to 1.22 dL/g. Besides the chemical imidization of 5c ( C ), the 5 ( C ) series were soluble in amide‐type solvents and even in less polar solvents, but PIs 5a – f prepared via thermal imidization were insoluble. PI films 5a – f exhibited tensile strengths ranging from 92 to 112 MPa, elongations at break from 8 to 15%, and initial moduli from 2.0 to 2.1 GPa. The glass‐transition temperatures of the 5 series were in the range of 232–278 °C, and the 10% weight‐loss temperatures were above 535 °C, with more than a 50% char yield at 800 °C in nitrogen. In comparison of the PI 5 series with the analogous non‐fluorinated PIs 6 series based on 4,4′‐bis(4‐aminophenoxy)benzophenone, the 5 series revealed better solubility, lower color intensity, dielectric constant, and moisture absorption. Their PI films had cutoff wavelengths between 370 and 410 nm, b* values ranging from 9.6 to 58.3, dielectric constants of 3.05–3.64 (1 MHz), with moisture absorption in the range of 0.08–0.38 wt %. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 222–236, 2004 相似文献
14.
K. Wang S. Y. Yang L. Fan M. Sh. Zhan J. G. Liu 《Journal of polymer science. Part A, Polymer chemistry》2006,44(6):1997-2006
A series of molecular‐weight‐controlled fluorinated aromatic polyimides were synthesized through the polycondensation of a fluorinated aromatic diamine, 1,4‐bis(4′‐amino‐2′‐trifluoromethylphenoxy)benzene, with 4,4′‐oxydiphthalic anhydride in the presence of phthalic anhydride as the molecular‐weight‐controlling and end‐capping agent. Experimental results demonstrated that the resulting polyimides could melt at temperatures of 250–300 °C to give high flowing molten fluids, which were suitable for melt molding to give strong and flexible polyimide sheets. Moreover, the aromatic polyimides also showed good solubility both in polar aprotic solvents and in common solvents. Polyimide solutions with solid concentrations higher than 25 wt % could be prepared with relatively low viscosity and were stable in storage at the ambient temperature. High‐quality polyimide films could be prepared via the casting of the polyimide solutions onto glass plates, followed by baking at a relatively low temperature. The molten behaviors and organosolubility of the molecular‐weight‐controlled aromatic polyimides depended significantly on the polymer molecular weights. Both the melt‐molded polyimide sheets and the solution‐cast polymer films exhibited outstanding combined mechanical and thermal properties. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1997–2006, 2006 相似文献
15.
Novel fluorinated polyimides were prepared from an unsymmetrical diamine, 3‐methyl‐4‐(4‐amino‐2‐trifluoromethylphenoxy)‐4'‐aminobenzophenone ( 3 ), with four aromatic dianhydrides via a one‐step high‐temperature polycondensation procedure. All the obtained polyimides were soluble in some polar solvents such as NMP, DMAc, and DMF. Flexible and tough films were prepared by casting from polymer solution. These polyimide films exhibited high optical transparency, good mechanical and thermal properties. Moreover, they possessed low dielectric constants and low‐moisture absorption. Due to their properties, these fluorinated polyimides could be considered as photoelectric and microelectronic materials. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
16.
Chin-Ping Yang Sheng-Huei Hsiao Chin-Cheng Jang 《Journal of polymer science. Part A, Polymer chemistry》1995,33(9):1487-1493
1,6-Bis(4-aminophenoxy)naphthalene ( I ) was used as a monomer with various aromatic tetracarboxylic dianhydrides to synthesize polyimides via a conventional two-stage procedure that included ring-opening polyaddition in a polar solvent such as N,N-dimethylacetamide (DMAc) to give poly(amic acid)s, followed by thermal cyclodehydration to polyimides. The diamine ( I ) was prepared through the nucleophilic displacement of 1,6-dihydroxynaphthal-ene with p-chloronitrobenzene in the presence of K2CO3, followed by catalytic reduction. Depending on the dianhydrides used, the poly(amic acid)s obtained had inherent viscosities of 0.73–2.31 dL/g. All the poly(amic acid)s could be solution cast and thermally converted into transparent, flexible, and tough polyimide films. The polyimide films had a tensile modulus range of 1.53–1.84 GPa, a tensile strength range of 95–126 MPa, and an elongation range at break of 9–16%. The polyimide derived from 4,4′-sulfonyldiphthalic anhydride (SDPA) had a better solubility than the other polyimides. These polyimides had glass transition temperatures between 248–286°C (DSC). Thermogravimetric analyses established that these polymers were fairly stable up to 500°C, and the 10% weight loss temperatures were recorded in the range of 549–595°C in nitrogen and 539–590°C in air atmosphere. © 1995 John Wiley & Sons, Inc. 相似文献
17.
<正>聚芳醚(PAEs)具有优异的热稳定性和力学强度,已在航空航天、汽车和生物材料等获领域得了重要应用~([1,2]).将具有一定作用的功能性基团,如—F,—SO3H和—C≡CH等,引入到PAEs分子链中使这类材料获得特殊的性能是高性能高分子材料研究领域的重要课题~([3~5]).以Teflon~和Nafion~为代表的含氟聚合物在不粘涂层、燃料电池用质子交换膜和高效气体分离~([6~8]) 相似文献
18.
Chin‐Ping Yang Feng‐Zhi Hsiao 《Journal of polymer science. Part A, Polymer chemistry》2004,42(9):2272-2284
A novel fluorinated diamine monomer, 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)‐2,5‐di‐tert‐butylbenzene ( 2 ), was prepared through the nucleophilic substitution reaction of 2‐chloro‐5‐nitrobenzotrifluoride and 2,5‐di‐tert‐butylhydroquinone in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. Fluorinated polyimides ( 5a – 5f ) were synthesized from diamine 2 and various aromatic dianhydrides ( 3a – 3f ) via thermal or chemical imidization. These polymers had inherent viscosities of 0.77–1.01 dL/g. The 5 series polyimides were soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, and N,N‐dimethylformamide and were even soluble in dioxane, tetrahydrofuran, and dichloromethane. 5 (C) showed cutoff wavelengths between 363 and 404 nm and yellowness index (b*) values of 6.5–40.2. The polyimide films had tensile strengths of 93–114 MPa, elongations to break of 9–12%, and initial moduli of 1.7–2.1 GPa. The glass‐transition temperatures were 255–288 °C. The temperatures of 10% weight loss were all above 460 °C in air or nitrogen atmospheres. In comparison with a nonfluorinated polyimide series based on 1,4‐bis(4‐aminophenoxy)‐2,5‐di‐tert‐butylbenzene, the 5 series showed better solubility and lower color intensity, dielectric constants, and moisture absorption. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2272–2284, 2004 相似文献
19.
Chun-Shan Wang Rong-Wen Yang Kuo-Run Hsu 《Journal of polymer science. Part A, Polymer chemistry》1998,36(4):645-653
A series of novel perfluorononenyloxy group containing polyarylates were synthesized by a high-temperature solution condensation of 5-(perfluorononenyloxy)-isophthaloyl chloride ( II ) with various aromatic diols in o-dichlorobenzene. All the polyarylates were amorphous and readily soluble in many organic solvents such as o-chlorophenol, o-dichlorobenzene, chloroform, and polar aprotic solvents at room temperature or on heating. Transparent, tough, and flexible films of these polymers could be cast from the o-chlorophenol solutions. The polymers having inherent viscosity of 0.61–1.63 dL/g were obtained in quantitative yields. These polymers were thermally quite stable. The glass transition temperatures of these polyarylates were in the range of 219–242°C by DSC and 224–251°C by DMA, and the 10% weight loss temperatures in nitrogen and air were above 415 and 397°C, respectively. Moreover, these polymers maintained good mechanical properties (G′ ∼ 108 Pa) up to 220°C and had lower moisture absorption than common polyarylates. The dielectric constants of these polymers ranged from 3.23 to 3.75. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 645–653, 1998 相似文献
20.
Chin‐Ping Yang Yu‐Yang Su Sheng‐Huei Hsiao 《Journal of polymer science. Part A, Polymer chemistry》2006,44(20):5909-5922
Two series of novel fluorinated poly(ether imide)s (coded IIIA and IIIB ) were prepared from 2,6‐bis(3,4‐dicarboxyphenoxy)naphthalene dianhydride and 2,7‐bis(3,4‐dicarboxyphenoxy)naphthalene dianhydride, respectively, with various trifluoromethyl‐substituted aromatic bis(ether amine)s by a standard two‐step process with thermal or chemical imidization of the poly(amic acid) precursors. These fluorinated poly(ether imide)s showed good solubility in many organic solvents and could be solution‐cast into transparent, flexible, and tough films. These films were nearly colorless, with an ultraviolet–visible absorption edge of 364–386 nm. They also showed good thermal stability with glass‐transition temperatures of 221–298 °C, 10% weight loss temperatures in excess of 489 °C, and char yields at 800 °C in nitrogen greater than 50%. The 2,7‐substituted IIIB series also showed better solubility and higher transparency than the isomeric 2,6‐substituted IIIA series. In comparison with nonfluorinated poly (ether imide)s, the fluorinated IIIA and IIIB series showed better solubility, higher transparency, and lower dielectric constants and water absorption. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5909–5922, 2006 相似文献