共查询到20条相似文献,搜索用时 15 毫秒
1.
Kaveh Parvanak Boroujeni Irandokht Soltanian Amir Nasrolahi Shirazi 《Polymer Bulletin》2013,70(8):2411-2422
A series of new poly(1,2,4-triazole)s (PTAs) containing pyridine heterocyclic ring, bearing bulky aromatic pendent groups, were synthesized from the reaction of the corresponding polyhydrazides with aniline or 4-aminobenzenesulfonic acid in polyphosphoric acid (PPA) at 175 °C. The non-sulfonated PTAs showed glass transition temperatures (T gs) of 220–250 °C and inherent viscosities (η inh) equal to 0.48–0.78 dL/g, and the sulfonated poly(1,2,4-triazole)s (S-PTAs) exhibited T gs of 235–265 °C and inherent viscosities equal to 0.50–0.83 dL/g. The former polymers were soluble in conc. H2SO4 and partially soluble in hot N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), dimethylacetamide (DMAc), and 1-methyl-2-pyrrolidone (NMP), and the latter were soluble in DMF, NMP, DMSO and DMAc at room temperature. All polymers had useful levels of thermal stability and were stable up to 450 °C in nitrogen. The proton conductivities of undoped sulfonated polytriazole membranes and the acid-doped sulfonated polytriazole membranes lie in the range of 5 × 10?4–8.1 × 10?3 and 5 × 10?3–2.3 × 10?2 S/cm, respectively, at 90 °C and 100 % relative humidity. 相似文献
2.
Jie Shen Ying Zhang Mingfu Huang Wenhao Wang Zushun Xu Kelvin W. K. Yeung Changfeng Yi Ming Xu 《Journal of Polymer Research》2012,19(5):9857
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 %. 相似文献
3.
1,5-Bis(4-trimellitimido)naphthalene (II) was prepared by the condensation reaction of 1,5-naphthalenediamine and trimellitic anhydride. A series of aromatic poly(amide-imide)s
(IV
a–o) was synthesized by the direct polycondensation of the diimide-diacid (II) and various aromatic diamines (III
a–o). The reaction utilized triphenyl phosphite and pyridine as condensing agents in the presence of calcium chloride in N-methyl-2-pyrrolidone (NMP). The inherent viscosities of the resulting poly(amide-imide)s were in the range of 0.55∼1.39 dL/g.
These polymers were generally soluble in polar solvents, such as N,N-dimethylacetamide (DMAc), NMP, N,N-dimethylformamide (DMF). Flexible and tough poly(amide-imide) films were obtained by casting from a DMAc solution and had
tensile strengths of 90∼145 MPa, elongations to break of 5∼13 %, and initial moduli of 2.29∼3.73 GPa. The glass transition
temperatures of some poly(amide-imide)s were recorded in the range of 206∼218 °C, and most of the polymers did not show discernible
glass transition on their DSC traces. The 10% weight loss temperatures were above 522 °C in nitrogen and above 474 °C in air
atmosphere. 相似文献
4.
Four novel wholly para-oriented aromatic poly(ether-amide-hydrazide)s containing various pendant groups on their aromatic
rings were synthesized from p-aminosalicylic acid hydrazide (PASH) with an equimolar amount of either 4,4′-(1,4-phenylenedioxy)dibenzoyl
chloride (1a), 4,4′-(2,5-tolylenedioxy)dibenzoyl chloride (1b), 4,4′-(2-tert-butyl-1,4-phenylenedioxy)dibenzoyl chloride (1c),
or 4,4′-(2,5-biphenylenedioxy)dibenzoyl chloride (1d) via a low temperature solution polycondensation reaction. A polyamide-hydrazide
without the ether and pendant groups, poly[4-(terephthaloylamino)salicylic acid hydrazide, PTASH, is also investigated for
comparison. It was synthesized from PASH and terephthaloyl chloride by the same synthetic route. The polymer intrinsic viscosities
ranged from 4.5 to 2.47 dlg−1 in N,N-dimethyl acetamide (DMAc) at 30 °C and decreased with the introduction of the ether and pendant groups into the polymer.
All the polymers were soluble in DMAc, N,N-dimethyl formamide (DMF), and N-methyl-2-pyrrolidone (NMP) and their solutions
could be cast into flexible films with good mechanical strengths. Further, they exhibited a great affinity to water sorption.
Their solubility and hydrophilicity increased with introduction of the ether and pendant groups into the polymer. The prepared
polymers could be thermally cyclodehydrated under nitrogen atmosphere into the corresponding poly(ether-amide-1,3,4-oxadiazole)s
approximately in the region of 300–450 °C. The introduction of the flexibilizing ether linkages and the pendant groups into
the polymer improves the solubility of the resulting poly(ether-amide-1,3,4-oxadiazole)s compared to poly(amide-1,3,4-oxadiazole)
free from these groups. 相似文献
5.
A series of polyamides and poly(amide-imide)s were prepared by the direct polycondensation of 4,4′-[sulfonylbis(1,4-phenyleneoxy)]dianiline
or 4,4′-[sulfonylbis(2,6-dimethyl-1,4-phenyleneoxy)]dianiline with aromatic dicarboxylic acids and phthalimide unit-bearing
dicarboxylic acids in a N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride using triphenyl phosphite and pyridine as condensing
agents. The inherent viscosities of the resulting polymers were above 0.45 dL/g and up to 1.70 dL/g. Except for the polyamides
derived from terephthalic acid and 4,4′-biphenyldicarboxylic acid, all the other polyamides and all poly(amide-imide)s were
readily soluble in polar organic solvents such as NMP, N, N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and m-cresol, and afforded transparent and tough films by solution-casting. Most of the polymers showed distinct glass transition
on their differential scanning calorimetry (DSC) traces and their glass transition temperatures (Tg) stayed between 140–264 °C. The methyl-substituted polymers showed higher Tgs than the corresponding unsubstituted counterparts. The results of the thermogravimetry analysis (TGA) revealed that all
the methyl-substituted polymers showed lower initial decomposition temperatures than the unsubstituted ones. 相似文献
6.
Jian-Wen Jiang Xue-Liang Pei Shou-Ri Sheng Xiao-Yan Wu Xiao-Ling Liu Cai-Sheng Song 《Polymer Bulletin》2011,67(2):263-274
A series of new fluorine-containing polyamides were prepared directly by polycondensation of 2-(4-trifluoromethylphenoxy)terephthalic
acid with four trifluoromethyl-substituted aromatic bis(ether amine)s in N-methyl-2-pyrrolidone (NMP) solution containing dissolved calcium chloride using triphenyl phosphite and pyridine as condensing
agents. All the polymers showed excellent solubility in solvents such as NMP, N,N-dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, pyridine, tetrahydrofuran, and acetone at room temperature. These polymers had inherent
viscosities between 0.67 and 1.09 dL/g, and their weight-average molecular weights and number-average molecular weights were
in the range of 48,200–68,000 and 29,500–39,400, respectively. The resulting polymers showed glass-transition temperatures
between 189 and 214 °C and 10% weight loss temperatures ranging from 475 to 483 °C, and char yields at 800 °C higher than
50% in nitrogen. All polymers were amorphous and could be cast into transparent, flexible, and strong films from DMAc solutions
with tensile strengths of 71–115 MPa, elongations at break of 6–9%, and tensile moduli of 2.7–3.2 GPa. These polymers had
low dielectric constants of 3.14–3.31 (1 MHz), low moisture absorption in the range of 0.88–1.60%, and high transparency with
an ultraviolet–visible absorption cut-off wavelength in the 320–340 nm range. 相似文献
7.
A new symmetrical diamine monomer containing dioxypyrimidine and two diaryl imidazole bulky pendent group was synthesized
by the nucleophilic substitution reaction of 4,6 dihydroxy pyrimidine with the synthesized 2-(2-chloro-5-nitrophenyl)-4,5-diphenyl-1H-imidazole
(I). A series of novel fluorescent imidazole-containing polyamides (PAs) with inherent viscosities of 0.52–0.78 dL/g was prepared
by direct polycondensation of the diamine with various dicarboxylic acids. These PAs were readily soluble in many organic
solvents and could be solution-cast into tough and flexible films. The PAs exhibited glass transition temperatures (Tg)s between 202 and 260 °C, and 10% weight loss temperatures in the range of 345–470 °C in air. In addition, three novel polyimides
(PIs) with inherent viscosities of 0.38–0.56 dL/g were prepared by addition reaction of the diamine with commercially available
tetracarboxylic dianhydrides and subsequent chemical imidization. The PIs exhibited good solubility in polar solvents such
as NMP. These polymers exhibited Tgs in the range of 237–285 °C and their 10% weight-loss temperatures varied from 440 to 520 °C. 相似文献
8.
Marioara Nechifor 《Journal of Polymer Research》2011,18(6):2477-2485
A dicarboxylic acid bearing two cinnamic acids units linked in their para positions by a methylene bridge was synthesized by the reaction of 4,4′-methylene-bis(benzaldehyde) and malonic acid, characterized
by spectral and elemental analysis and used to prepare a series of novel photocrosslinkable aromatic polyamides through its
reaction with various ether-bridged aromatic diamines. 1H and 13C NMR, IR and UV spectroscopy confirmed the structure of the monomer and photopolymers. The resulting polymers with inherent
viscosities of 0.65–1.14 dL/g were soluble in polar aprotic solvents, such as DMF, DMSO, DMAc and NMP, and showed good film-forming
properties. Their weight-average and number-average molecular weights, determined by GPC (polystyrene standard), were in the
range 57,400–84,300 and 24,000–40,900, respectively. The percent of water absorbed at 65% relative humidity varied between
1.57% and 2.35%. The polyamides exhibited glass transition temperatures between 202 and 239 °C, and they were stable up to
a temperature of 350 °C in air. Wide-angle X-ray scattering diagrams did not show any crystalline reflection and no endothermic
peak attributable to polymer melting was observed in DSC curves of the polymers. These photosensitive polymers exhibited strong
UV absorption maxima both in solution and film state, and displayed three photochemical transformations under the UV exposure,
viz. a trans-cis isomerization, favored in the early stage of UV irradiation, a bimolecular cyclodimerization, leading to the generation of
a cyclobutane ring, and a photo-Fries rearrangement evidenced only in polymer solutions. 相似文献
9.
The 4‐[4′‐(Hydrazinocarbonyl)phenoxy]‐2‐pentadecylbenzohydrazide was polycondensed with aromatic diacid chlorides viz., terephthalic acid chloride (TPC), isophthalic acid chloride (IPC), and a mixture of TPC : IPC (50 : 50 mol %) to obtain polyhydrazides which on subsequent cyclodehydration reaction in the presence of phosphoryl chloride yielded new poly(1,3,4‐oxadiazole)s bearing flexibilizing ether linkages and pentadecyl side chains. Inherent viscosities of polyhydrazides and poly(1,3,4‐oxadiazole)s were in the range 0.53–0.66 dL g?1 and 0.49–0.53 dL g?1, respectively, indicating formation of medium to reasonably high molecular weight polymers. The number average molecular weights (Mn) and polydispersities (Mw/Mn) of poly(1,3,4‐oxadiazole)s were in the range 14,660–21,370 and 2.2–2.5, respectively. Polyhydrazides and poly(1,3,4‐oxadiazole)s were soluble in polar aprotic solvents such as N,N‐dimethylacetamide, 1‐methyl‐2‐pyrrolidinone, and N,N‐dimethylformamide. Furthermore, poly(1,3,4‐oxadiazole)s were also found to be soluble in solvents such as chloroform, dichloromethane, tetrahydrofuran, pyridine, and m‐cresol. Transparent, flexible, and tough films of polyhydrazides and poly(1,3,4‐oxadiazole)s could be cast from N,N‐dimethylacetamide and chloroform solutions, respectively. Both polyhydrazides and poly(1,3,4‐oxadiazole)s were amorphous in nature and formation of layered structure was observed due to packing of pentadecyl chains. A decrease in glass transition temperature was observed both in polyhydrazides (143–166°C) and poly(1,3,4‐oxadiazole)s (90–102°C) which could be ascribed to “internal plasticization” effect of pentadecyl chains. The T10 values, obtained from TG curves, for poly(1,3,4‐oxadiazole)s were in the range of 433–449°C indicating their good thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124:1281–1289, 2012 相似文献
10.
Shanyin Yan Wenqiu Chen Xiaojin Yang Chuan Chen Mingfu Huang Zushun Xu Kelvin W. K. Yeung Changfeng Yi 《Polymer Bulletin》2011,66(9):1191-1206
A novel pyridine-containing aromatic diamine monomer, 4-phenyl-2,6-bis[3-(4-aminophenoxy)phenyl]pyridine (m,p-PAPP), was successfully synthesized by a modified Chichibabin reaction of benzaldehyde and a substituted acetophenone, 3-(4-nitrophenoxy)acetophenone
(m,p-NPAP), followed by a reduction of the resulting dinitro compound 4-phenyl-2,6-bis[3-(4-nitrophenoxy)phenyl]pyridine (m,p-PNPP) with Pd/C and hydrazine monohydrate. The aromatic diamine was employed to synthesize a series of pyridine-containing
polyimides (PIs) by polycondensation with various aromatic dianhydrides in N,N-dimethylformamide (DMF) via the conventional two-step method, and further thermal or chemical imidization forming PIs. The
inherent viscosities of the resulting poly(amic acid)s and PIs were 0.59–0.73 and 0.56–0.68 dL/g; most of the PIs obtained
by chemical imidization were readily soluble in common organic solvents such as DMF, N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), tetrahydrofuran (THF), etc. Meanwhile, strong and flexible PI films were obtained, which had
good thermal stability, with the glass transition temperature (T
g) of 204.5–237.4 °C and the temperature at 10% weight loss of 527.7–552.0 °C in nitrogen atmosphere, as well as outstanding
mechanical properties with tensile strengths of 88.6–90.4 MPa, a tensile moduli of 1.04–1.56 GPa, and elongations at break
of 7.2–8.7%. The PI films also were found to possess low water uptake of 0.89–0.98%. 相似文献
11.
Summary
A series of new aromatic poly(amide-imide)s were synthesized by the triphenyl phosphite activated polycondensation of the
diimide-diacid, 2,5-bis(trimellitimido)toluene (I) with various aromatic diamines. The poly(amide-imide)s had inherent viscosities of 0.69–1.89 dL/g. Most of the resulting
polymers showed an amorphous nature and were readily soluble in a variety of organic solvents. Transparent, flexible, and
tough films of these polymers could be cast from DMAc or NMP solutions. Their cast films had tensile strengths ranging from
76 to 112 MPa, elongations at break from 8 to 31%, and initial moduli from 2.20 to 2.99 GPa. The glass transition temperatures
of these polymers were in the range of 253–328°C.
Received: 25 September 1998/Revised version: 2 December 1998/Accepted: 8 December 1998 相似文献
12.
Summary
A series of new aromatic poly(amide-imide)s were synthesized by the triphenyl phosphite activated polycondensation of the
diimide-diacid, 1,4-bis(trimellitimido)-2,5-dimethylbenzene (I), with various aromatic diamines. The poly(amide-imide)s had inherent viscosities of 1.13–2.22 dL/g. Most of the resulting
polymers showed an amorphous nature and were readily soluble in a variety of organic solvents. Transparent, flexible, and
tough films of these polymers could be cast from DMAc or NMP solutions. Their cast films had tensile strengths ranging from
64 to 116 MPa, elongations at break from 6 to 20%, and initial moduli from 2.18 to 3.90 GPa. The glass transition temperatures
of these polymers were in the range of 247–324°C.
Received: 13 April 1999/Revised version: 28 May 1999/Accepted: 26 June 1999 相似文献
13.
A series of new aromatic poly(amide–imide)s (PAIs) was synthesized by triphenyl phosphite‐activated polycondensation of the diimide–diacid, 1,4‐bis(trimellitimido)‐2,3,5,6‐tetramethylbenzene (I), with various aromatic diamines in a medium consisting of N‐methyl‐2‐pyrrolidone (NMP), pyridine, and calcium chloride. The PAIs had inherent viscosities of 0.82–2.43 dL/g. The diimide–diacid monomer (I) was prepared from 2,3,5,6‐tetramethyl‐p‐phenylenediamine with trimellitic anhydride (TMA). Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including NMP, N,N‐dimethylacetamide (DMAc), and N,N‐dimethylformamide (DMF). Transparent, flexible, and tough films of these polymers could be cast from DMAc solutions. Their cast films had tensile strengths ranging from 80 to 95 MPa, elongation at break from 10 to 45%, and initial modulus from 2.01 to 2.50 GPa. The 10% weight loss temperatures of these polymers were above 510°C in nitrogen. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1162–1170, 2000 相似文献
14.
A series of new polyhydrazides has been synthesized via direct polycondensation of benzofuro[2,3‐b]benzofuran‐2,9‐dicarboxylic acid (BBDA) with dihydrazides in ionic liquids (ILs) as a new class of solvents, which have interesting properties, such as nonvolatility, high ionic concentration, good thermal stability, and nonflammability. Direct polycondensation is successfully proceeded in ILs and triphenyl phosphite (condensing agent) without any additional extra components, such as LiCl and pyridine, using in similar reactions in ordinary (IL can act as both solvent and catalyst). The polyhydrazides have been obtained in quantitative yield and their intrinsic viscosities ranged from 0.21 to 0.47 dL g?1. The polyhydrazides were characterized by means of IR, 1H‐NMR, inherent viscosity (ηinh), solubility test, TGA, DSC, CHN analysis, and ultraviolet λmax. They could be thermally converted into the corresponding poly(1,3,4‐oxadiazole)s approximately in the region of 210–330°C, as evidenced by the TGA thermograms. The polymers were readily soluble in several organic polar solvents, such as DMAc, N,N‐dimethylformamide, dimethylsulfoxide, N‐methyl‐2‐pyrrolidone and could be cast into flexible films. The polymer were metallized via complexation with various transition metal. The complexes were investigated by X‐ray diffraction, IR, and UV spectrophotometry. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
15.
Mohammad Reza Vakili Saeed Zahmatkesh Tahereh Jafarizadeh Mohammad Javad Panahiyan 《Polymer Bulletin》2012,68(1):85-94
N-trimelliticimido-l-aspartic acid (1) was prepared from the reaction of trimellitic anhydride with l-aspartic acid in a mixture of glacial acetic acid and pyridine solution (3/2 ratio) under refluxing conditions. The solution
polycondensation of the corresponding activated monomer with eight aromatic diamines were carried out in DMAc. The resulting
poly(amide-imide)s were obtained in quantitative yields, showed admirable inherent viscosities (0.20–0.36 dl g−1), good optical activity (+7.32o to +15.24o), and were readily soluble in polar aprotic solvents. They start to decompose
(T
10%) above 170 °C and display glass-transition temperatures at 120–237 °C. All of the above polymers were fully characterized
by UV, FT–IR, and 1HNMR spectroscopy, elemental analysis, thermogravimetric analyses, DSC, inherent viscosity measurement, and specific rotation. 相似文献
16.
Summary
New dianhydrides having alkyloxy side chains were synthesized and polymerized with 4,4'-oxydianiline in NMP. Chemically cyclized
polyimides were obtained with inherent viscosities of 0.30∼0.84 dL/g range. All the polymers were highly soluble in polar
solvent such as NMP at room temperature. TGA pyrograms showed two-step degradation and in DSC thermograms the polymers exhibited
Tgs between 124°C and 259°C. Wide-angle X-ray diffractograms revealed very low crystallinity and layered structure, which was
better developed in the polymers with longer side chains
Received: 16 October 2000/Accepted: 10 November 2000 相似文献
17.
Synthesis and characterization of poly(aryl ether ketone)s with fluorinated phenyl in the side chain
New bisphenol monomers, (4-fluorophenyl)hydroquinone (3b) and (3,4-difluoro phenyl)hydroquinone (3c), were synthesized in a two-step synthesis. Poly(aryl ether ketone)s (PAEKs) (4a–c) were derived from these fluorinated bisphenols and nonfluorinated bisphenol—phenylhydroquinone (3a) with 4,4′-diflourobenzophenone via a nucleophilic aromatic substitution polycondensation. The obtained polymers had inherent
viscosities of 0.50–0.92 dL/g. Thermal analysis showed that the obtained PAEKs had excellent thermal properties, the glass
transition temperatures ranged from 148 to 160 °C, and the temperatures at 5% weight loss (Td5) were above 527 °C and the temperatures at 10% weight loss (Td10) were above 544 °C in nitrogen. All the polymers showed excellent solubility and could dissolve in common organic solvents,
such as DMSO, NMP, DMF, etc. So the films of them were easily cast from their solutions, which possessed good mechanical properties,
with tensile strengths of 95.2–104.0 MPa, Young’s moduli of 2.68–3.06 GPa, and elongation at break of 15–32%. Furthermore,
the prepared PAEKs displayed low dielectric constants (2.75–2.95 at 1 MHz) and hydrophobic character (contact angles for water:
83.9o–98.4o). 相似文献
18.
Summary
New pyromellitic dianhydrides having (n-alkyloxy)phenyloxy (-O-Ph-O-n-CmH2m+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 (Cm-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 Tg'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 相似文献
19.
Shou‐Ri Sheng Chun‐Xin Ma Jian‐Wen Jiang Zhen‐Zhong Huang Cai‐Sheng Song 《应用聚合物科学杂志》2010,116(3):1650-1659
Two novel monomers, 9,9‐bis[4‐(4‐carboxyphenoxy)phenyl]xanthene (BCAPX) and 9,9‐bis[4‐(4‐aminophenoxy)phenyl]xanthene (BAPX) were prepared in two main steps starting from nucleophilic substitution of 9,9‐bis(4‐hydroxyphenyl)xanthene (BHPX) with p‐fluorobenzonitrile and p‐chloronitrobenzene, respectively. Using triphenyl phosphite and pyridine as condensing agents, two series of polyamides containing xanthene cardo groups with the inherent viscosities (0.82–1.32 dL/g) were prepared by polycondensation from BCAPX with various aromatic diamines or from BAPX with various aromatic dicarboxylic acids in an N‐methyl‐2‐pyrrolidone (NMP) solution containing dissolved calcium chloride, respectively. All new polyamides were amorphous and readily soluble in various polar solvents such as N,N‐dimethylformamide (DMF), NMP, N,N‐dimethylacetamide (DMAc) and pyridine. These polymers showed relatively high glass transition temperatures between 264 and 308°C, decomposition temperatures at 10% weight loss ranging from 502 to 540°C and 488 to 515°C in nitrogen and air, respectively, and char yields at 800°C in nitrogen higher than 56%. Transparent, flexible, and tough films of these polymers cast from DMAc solutions exhibited tensile strengths ranging from 86 to 109 MPa, elongations at break from 13 to 22%, and initial moduli from 2.15 to 2.63 GPa. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
20.
A new aromatic diamine with a trifluoromethyl pendent group, 1,4-bis((4-amino-2-(trifluoromethyl)phenoxy)methyl)cyclohexane,
was successfully synthesized in two steps from 1,4-cyclohexanedimethanol and 2-chloro-5-nitrobenzotrifluoride as starting
materials. And the newly obtained diamine with various aromatic dicarboxylic acids, including isophthalic acid (IPA), 2,2-bis(4-carboxy-phenyl)hexafluoropropane
(6FA) and 4,4′-oxydibenzoic acid (OBA), were polymerized, respectively via the usual Yamazaki reaction to prepare a series
of fluorinated polyamides. The resulting polymers had inherent viscosities ranging from 1.85 to 2.36 dL/g. All the polymers
showed outstanding solubility and could be easily dissolved in amide-type polar aprotic solvents [e.g., N-methyl-2-pyrrolidone (NMP), DMAc, and DMF] and even dissolved in less polar solvents (e.g., pyridine, and tetrahydrofuran).
These polymers could also be easily be cast into transparent, tough and flexible films with tensile strengths of 76.5–82.3 MPa,
Young’s moduli of 1.64–1.85 GPa, and elongations at break of 10–12%. In addition, these polyamides films exhibited low dielectric
constants of 2.37–2.53 at 100 MHz, low water absorptions in the range of 1.54–2.13%, and high transparency with an ultraviolet–visible
absorption cut-off wavelength in the 326–333 nm range. Furthermore these polyamides still retained good thermal stability.
These combined outstanding features make these obtained polyamides competitive for advanced microelectronic applications. 相似文献