首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
<正> 在合成聚酰胺的研究中,关于由N-羟基化合物O,O′-双酰基衍生物与二元胺在温和条件下合成聚酰胺的报道较少。Overberger及ebenda首先研究了N-羟基丁二酰亚胺的双活性酯及N-羟基邻苯二甲酰亚胺的双活性酯与派嗪间的缩聚反应。Ueda、Imai等则报道了另两类活性双酯,如1-羟基苯并三氮唑的双活性酯及O,O′-间苯二甲酰双肟与二元胺间的缩聚合成聚酰胺的结果。  相似文献   

2.
Aliphatic–aromatic polyamides were synthesized by the palladium-catalyzed polycondensation of aliphatic diamines, aromatic dibromides, and carbon monoxide. The effects of variables, such as the kind and amount of base, reaction temperature, and the kind of palladium catalyst were investigated in detail on the reaction of hexamethylenediamine and bis(4-bromophenyl) ether with carbon monoxide. Inherent viscosities of the polyamides were between 0.13 and 1.21 dL/g and varied markedly with the structure of the diamine component. Solubility of the polyamides decreased with increase of chain length of aliphatic diamines, and the polyamides derived from p-dibromobenzene was insoluble in organic solvents except for m-cresol. Polyamides obtained from primary aliphatic diamines began to decompose at 210–250°C in air due to decomposition of the aliphatic chain.  相似文献   

3.
Abstract

5‐tert‐Butyl‐isophthalic acid (TIPA) was polycondensed with three different aromatic diamines by means of triphenylphosphite (TPP) and pyridine. The resulting polyamides were characterized by solution viscosities and MALDI‐TOF mass spectra (m.s.). These m.s. revealed significant fractions of cyclic oligo‐ and polyamides in all samples. In polyamides of high molecular weight, only cycles were detectable (observed up to masses of 13,000 Da). Three poly(amide‐imide)s were prepared by TPP‐mediated polycondensation of trimellitic anhydride (TMA) and three aromatic diamines. Although relatively high molar masses were obtained, the MALDI‐TOF m.s. displayed the peaks of linear chains in addition to those of cyclic polymers. The results together suggest that the side reactions mainly occur at the amino endgroups.  相似文献   

4.
For aromatic and aliphatic diamines of significantly different basicities, the kinetics of acylation with phthalic anhydride in glacial acetic acid in the range 16–70°C and of imidization of corresponding bis(o-carboxyamides) in acetic acid at 140°C has been studied. The reactions under study model the stages of polycondensation and intramolecular cyclization, respectively, in the high-temperature catalytic synthesis of polyimides in molten benzoic acid. It has been established that the acylation of amino groups in acetic acid proceeds as a reversible reaction and is catalyzed by the acidic medium. The kinetic and thermodynamic parameters of the above-mentioned model reactions have been determined, and the effect of the chemical structure of diamines on these parameters has been assessed. On the basis of the experimental data obtained for the model reactions, it is inferred that, in the synthesis of polyimides in benzoic acid, the overall rate of the process is determined by the rate of the intramolecular cyclization. A low sensitivity of the cyclization reaction to a change in the structure of the starting diamines explains why high-molecular-mass polyimides can be prepared at comparable rates under these conditions from both high-and low-basicity diamines.  相似文献   

5.
The effect of the solvent on the inherent viscosity of polyamides was investigated in the polycondensation of new active 1-benzotriazolyl diesters, such as 1,1′-(adipolydioxy)bisbenzotriazole and 1,1′-(isophthaloyldioxy)bisbenzotriazole, with diamines. The preferred polymerization media were polar aprotic solvents, including N-methyl-2-pyrrolidone and hexamethylphosphoramide. The solution polycondensation at room temperature afforded a series of polyamides having inherent viscosities as high as 1.8 from both aliphatic and aromatic diamines. The 1-benzotriazolyl diesters were more reactive than di(2,4-dinitrophenyl) isophthalate toward diamines. Prior to polymer synthesis, the aminolysis of some active monoesters was carried out as a model compound study.  相似文献   

6.
Photoreactive polyamides having m- or 1 -type cyclobutane moiety were prepared via a topochemical photodimerization of 4-(3-oxo-3-phenyl-1-propenyl)benzoic derivatives,4 followed by polycondensation of cyclobutane dicarboxylate derivatives with diamines. From the spectral studies of resulted polyamides compared with the corresponding reference diamides, it was concluded that both types of polyamides were depolymerized photochemically to give the same type of amide derivative having chalcone moiety with a small amount of undefined side reaction. The cyclobutane ring of the m-dimer from 4-(3-oxo-3-phenyl-1-propenyl)benzoic acid in crystal is severely twisted presumably because of the enhanced steric repulsions between two pairs of adjacent substituents. The higher quantum yield of the m-dimer for the photocleavege, compared with that of the 1 -dimer, has been interpreted in terms of such steric repulsions by the strained structure of the m-dimer.  相似文献   

7.
Two new routes to polyamides were established, based on the polycondensation of two new typical active diesters: the active diester of N-hydroxy-5-norbornene-2,3-dicarboximide, such as N,N′-(terephthaloyldioxy)bis(5-norbornene-2,3-dicarboximide), and the active diester of 3-hydroxy-4-oxo-3,4-dihydro-1,2,3-benzotriazine, such as 3,3′-(isophthaloyldioxy)bis(4-oxo-3,4-dihydro-1,2,3-benzotriazine) with diamines. The polycondensation occurred at room temperature in solution without added catalyst. Dipolar aprotic solvents which included dimethyl sulfoxide and N-methyl-2-pyrrolidone were used as solvents for polymerization. Before polymer synthesis the aminolysis of two active monoesters was carried out as a model compound study.  相似文献   

8.
A new synthetic route to polyamides and hydroxyl polyamides was established, based on the selecting (?)-acylation of three novel typical active diesters: the active diester of N-hydroxy- (?) 4-epoxy-5-cyclohexene-2, 3-dicarboximide( HOEC), such as N, N'-(temphthaloyldioxy) bis(1, 4- epoxy - 5 - cyclohexene- 2, 3 - dicarboximide.) ( PBOEC), N, N'- ( isophthaloyl - dioxy) bis (1,4-epoxy-5-cyclohexene-2, 3-dicarboximide)(IPBOEC) and N, N' -(adipoyldioxy) his (1,4-epoxy-5-cyclohexene-2, 3-dicarboximide) ( ADOEC)with aliphatic diamines and 1,3-diamino-2-hydroxypropane. The polycondensation occurs at room temperature in solution without added catalyst. Dipolar aprotic solvents which include dimethyl sulfoxide, N- methyl - 2- pyrrolidone and dimethylformamide were used as solvents for polymerization. The selective N-acylation of two active diesters was performed as a model reaction study.  相似文献   

9.
The synthesis of a new bis(ether carboxylic acid), 2,2′‐bis(4‐carboxyphenoxy)‐9,9′‐spirobifluorene, in which two orthogonally arranged carboxyphenoxyfluorene entities are connected through an sp3 carbon atom (the spiro center), is reported. The direct phosphorylation polycondensation of this diacid monomer with various aromatic diamines yields aromatic polyamides containing 9,9′‐spirobifluorene moieties in the main chain. The presence of the spiro segment restricts the close packing of the polymer chains and decreases interchain interactions, resulting in amorphous polyamides with enhanced solubility, and high glass‐transition temperatures and good thermal stability are maintained through controlled segmental mobility. The glass‐transition temperatures of these polyamides are in the range of 234–306 °C, with 10% weight losses occurring at temperatures above 530 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1160–1166, 2003  相似文献   

10.
A set of new aromatic polyamides containing ether and benzonorbornane units were synthesized by the direct phosphorylation polycondensation of 3,6‐bis(4‐carboxyphenoxy)benzonorbornane with various aromatic diamines. The polymers were produced in high yields and moderate to high inherent viscosities (0.64–1.70 dL/g). The polyamides derived from rigid diamines such as p‐phenylenediamine and benzidine were semicrystalline and insoluble in organic solvents. The other polyamides were amorphous and organosoluble and afforded flexible and tough films via solution casting. These films exhibited good mechanical properties, with tensile strengths of 95–101 MPa, elongations at break of 13–25%, and initial moduli of 1.97–2.33 GPa. The amorphous polyamides showed glass‐transition temperatures between 176 and 212 °C (by differential scanning calorimetry) and softening temperatures between 194 and 213 °C (by thermomechanical analysis). Most of the polymers did not show significant weight loss before 450 °C in nitrogen or in air. Some properties of these polyamides were also compared with those of homologous counterparts without the pendent norbornane groups. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 947–957, 2002  相似文献   

11.
1,6-Diamantane dicarboxvlic acyl chloride ( I ) was used as a monomer with various aromatic diamines to synthesize polyamides by interfacial polycondensation and solution polycon-densation. The polyamides prepared by interfacial polycondensation had inherent viscosities between 0.38 and 0.15 dL/g. The polyamides prepared by solution polycondensation had inherent viscosities between 0.62 and 0.25 dL/g. The polyamides IIIa prepared by solution polycondensation showed the main melting transition at 380°C by dynamic mechanical analysis. In addition, it was quite temperature-stable and maintained good mechanical properties (G′?108 Pa) up to high temperatures close to the main transition well above 350°C. The polyamide IIIA had a tensile strength of 35 MPa, elongations to break of 10%, and initial modulus of 0.8 GPa. Some of the polyamides were soluble in NMP, DMAc, and DMSO, depending on soft segment moiety of diamine ( II ). The polyamides prepared by interfacial polycondensation have a greater tendency to form crystal than those prepared by solution polycondensation, as evidenced by x-ray diffraction studies. These polyamides had glass transition temperatures in the 270–300°C range, and 5% weight loss temperatures up to 435°C in nitrogen. © 1995 John Wiley & Sons, Inc.  相似文献   

12.
Direct polycondensation of aromatic dicarboxylic acids and diamines with phosphorus oxychloride (POC) was successfully carried out to give polyamides of high inherent viscosity, when POC was reacted selectively and completely with a two molar quantity of carboxyl groups. To achieve the selective and complete reaction, factors, such as the amount of POC used, reactions of POC with the dicarboxylic acids by adding of POC to the acids or its reverse addition under various conditions, and aging after addition were fully examined. The reaction was proposed to proceed via a bifunctional cyclic phosphoric–carboxylic anhydride through stepwise reaction of POC with carboxyl groups.  相似文献   

13.
New diamines containing amide and oxyethylene linkages were prepared by reduction of the corresponding dinitro compounds which were obtained by the reaction of p-nitrophenol with arylenebis(2-oxazolines) in dimethylformamide at 130°C. Moderate- to high-molecular-weight polyamides and polyamide-imides containing oxyethylene linkages were prepared by the polycondensation of the diamines with diacid chlorides and tetracarboxylic acid dianhydrides, respectively. The polyamides were soluble in dimethylacetamide containing 5% of lithium chloride and dichloroacetic acid, while the polyamide-imides dissolved only moderately in the latter solvent. Thermogravimetric analysis showed that thermo-oxidative decomposition started at 310–330°C and at around 325°C for the polyamides and polyamide-imides, respectively.  相似文献   

14.
Novel examples were presented of the use in polyamide synthesis of active 2-benzothiazolyl dithiolesters for which aminolysis is assisted by a neighboring group. Solution polycondensation of new dithiolesters, 2,2′-(adipoyldithio)bisbenzothiazole and 2,2′-(isophtahloyldithio)bisbenzothiazole, with both aliphatic and aromatic diamines in polar aprotic solvents (N-methyl-2-pyrrolidone and hexamethylphosphoramide) took place rapidly at room temperature yielding polyamides with high molecular weight. The interfacial polycondensation in a chloroform–water system was also successful for polyamide formation. S,S′-Di-p-nitrophenyl dithioisophthalate reacted much more slowly toward diamines than the 2-benzothiazolyl dithiolesters. Prior to polymer synthesis, the aminolysis of active monothiolesters was carried out as a model compound study.  相似文献   

15.
We have investigated a novel monomer having a pendent phenyl imide group for preparing new cycloaliphatic-aromatic polyamides. Novel polyamides were synthesized by a direct polycondensation reaction of N-phenyl-2,3-imide cyclopentane-1,4-dicarboxylic acid (PCPA) and various aromatic diamines. A direct polycondensation was carried out by a Yamazaki's direct polycondensation that is typical of using triphenyl phosphite, lithium chloride, and pyridine. Inherent viscosity of these resulting polyamides was in the range 0.47–1.05 dL/g. The glass transition temperatures of these polyamides were in the range of 190–200°C. The decomposition temperatures of them were in the range of 310–323°C in nitrogen atmosphere. The Solubility of these polyamides are good in aprotic solvents such as DMAc (N,N-Dimethylacetamide), NMP (N-Methyl-2-Pyrrolidinone) and DMF (N,N-Dimethylformamide). Transparent, flexible, and tough films were cast from DMAc solutions.  相似文献   

16.
The Diels–Alder adduct of levopimaric acid with acrylonitrile was efficiently prepared from resin acids. Excellent addition reaction yields (ca. 95%) were obtained. The adduct was converted into polyamides by polycondensation with diamines. When the same adduct was subjected to a dehydrodecarboxylation reaction, a novel ketone dinitrile derivative was obtained. This trifunctional product was also converted into polyamides by polycondensation with diamines. When the ketone dinitrile was hydrolyzed in the presence of alkalies and the reaction product was chlorinated, a ketone diacid chloride was obtained. A polyester was synthesized by the polycondensation of the diacid chloride with a diol. The structures of the Diels–Alder adduct, ketone dinitrile derivative, ketone diacid chloride, and polymers were established by means of elemental analysis, IR and NMR spectroscopy, and molecular weight determinations. Both the polyamides and the polyester were low‐molecular‐weight polymers soluble in polar solvents. The thermal behavior of the monomers and polymers was evaluated by thermogravimetric analysis. The thermal studies showed that the polymers were fairly thermostable substances, except the polyester, which appeared to be a substance with good thermal stability. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6308–6322, 2005  相似文献   

17.
Two new routes to polyamides and polyesters were established, based on the polycondensationof new typical active diacylamide of benzotriazole, such as 1, 1'-(isophthaloyl) bisbenzotriazole(IPBBT) and 1, 1'-(terephthaloyl)bisbenzotriazole (PBBT) with diamines, diols and diphenol underdifferent mild conditions. The N-acylation of polycondensation occurred at room temperaturewithout added catalyst, the O-acylation of polycondensation had to complete in the presence oftriethylamine as a catalyst at 60℃.  相似文献   

18.
A Phenazasiline ring was incorporated into a polymer backbone by polycondensation of 2,8-dichloroformyl-5,10-dihydro-5-methyl-10,10-diphenylphenazasiline (V) with aromatic diamines or bisphenols, and phenazasiline-containing polyamides and polyesters were obtained. The polyamides were prepared by low-temperature solution polycondensation in N-methyl-2-pyrrolidone (NMP) in the presence of lithium chloride. The polyesters were synthesized by interfacial polycondensation in a mixture of 1,2-dichloroethane and aqueous alkali in the presence of tetrabutylammonium chloride as an accelerator. These reaction conditions gave the corresponding polymers with high viscosities. The phenazasiline-containing polyamides exhibited good solubilities in polar aprotic solvents such as dimethylformamide, dimethylacetamide, and NMP, and also in m-cresol, although the polyesters showed limited solubilities in organic solvents. Under nitrogen, the phenazasiline-containing polyamides and polyesters showed little degradation below 400°C and had good heat resistance.  相似文献   

19.
A new ether‐bridged aromatic dicarboxylic acid, 2′,5′‐bis(4‐carboxyphenoxy)‐p‐terphenyl ( 3 ), was synthesized by the aromatic fluoro‐displacement reaction of p‐fluorobenzonitrile with 2′,5′‐dihydroxy‐p‐terphenyl in the presence of potassium carbonate, followed by alkaline hydrolysis. A set of new aromatic polyamides containing ether and laterally attached p‐terphenyl units was synthesized by the direct phosphorylation polycondensation of diacid 3 with various aromatic diamines. The polymers were produced with high yields and moderately high inherent viscosities (0.44–0.79 dL/g). The polyamides derived from 3 and rigid diamines, such as p‐phenylenediamine and benzidine, and a structurally analogous diamine, 2′,5′‐bis(4‐aminophenoxy)‐p‐terphenyl, were semicrystalline and insoluble in organic solvents. The other polyamides were amorphous and organosoluble and could afford flexible and tough films via solution casting. These films exhibited good mechanical properties, with tensile strengths of 91–108 MPa, elongations to break of 6–17%, and initial moduli of 1.95–2.43 GPa. These polyamides showed glass‐transition temperatures between 193 and 252 °C. Most of the polymers did not show significant weight loss before 450 °C, as revealed by thermogravimetric analysis in nitrogen or in air. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4056–4062, 2004  相似文献   

20.
《European Polymer Journal》1987,23(11):897-903
New polyamides containing thianthrene tetraoxide were synthesized from 2,7-dichloroformylthianthrene-5,5′,10,10′-tetraoxide (A) and various diamines by the low temperature solution polycondensation technique. The resulting polyamides were characterized by i.r. and 1H-NMR spectra and elemental analysis. The polyamides had inherent viscosities of 0.56–1.21 dl/g in DMA at 30°. All the polymers dissolved readily at room temperature in polar aprotic solvents. Density, crystallinity and thermal stability of these polyamides have been determined. In order to characterize the polymers, a model compound was also prepared from A and p-toluidine.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号