Synthesis and Properties of Novel Optically Active and Soluble Aromatic/Aliphatic Polyimides via Reaction of Dianhydrides and Diisocyanates (original) (raw)
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Synthesis and properties of novel diisocyanate based optically active polyimides
European Polymer Journal, 2002
A new optically active diisocyanate was prepared from the reaction of L -leucine and pyromellitic dianhydride (PMDA) and subsequent transformation of intermediate imide-containing diacid to diisocyanate via Weinstock modification of Curtius rearrangement. Solution polycondensation reaction of the prepared diisocyanate with PMDA, 3,3,4,4-benzophenonetetracarboxylic dianhydride, and hexafluoroisopropylidene 2,2-bis(phthalic anhydride) resulted in the preparation of novel optically active polyimides. The optimal conditions for polyimidations (reaction duration and temperature programming) were obtained via study of the model compound. The monomer, model compound and polymers were characterized by FTIR, 1 HNMR, mass spectroscopy and elemental analysis and their optical and physical properties were studied as well.
Synthesis and properties of novel optically active polyimides
Journal of Polymer Science Part A: Polymer Chemistry, 2001
The dehydrochlorination coupling polymerization of N-(3,5diethynylbenzoyl)-L-alanine dodecylamide 1 with platinum (Pt) chlorides having pyridine, bipyridine, and phenanthroline ligands 2a2d gave novel optically active poly(phenyleneethynylene)s [poly(1-2a)poly(1-2d)] bearing Pt in the main chains. The Z-average diameters of the polymers ranged from 453 to 1081 nm. Poly(1-2a) exhibited CD signals assignable to aggregates, and formed regulated twisted structures with height of 540 « 70 nm and pitch of 62 « 6 nm, which were confirmed by AFM measurements.
Synthesis and characterization of some novel aromatic polyimides
European polymer journal, 2005
Three new diamines 1,2-di(p-aminophenyloxy)ethylene, 2-(4-aminophenoxy)methyl-5-aminobenzimidazole and 4,4-(aminopheyloxy) phenyl-4-aminobenzamide were synthesized and polymerized with 3,3 0 ,4,4 0 -benzophenone tetracarboxylic acid dianhydride (BP), 4,4 0 -(hexafluoroisopropyledene)diphthalic anhydride (HF) and 3,4,9,10-perylene tetracarboxylic acid dianhydride (PD) either by one step solution polymerization reaction or by two step procedure. The later includes ring opening poly-addition to give poly(amic acid), followed by cyclodehydration to polyimides with the inherent viscosities 0.62-0.97 dl/g. Majority of polymers are found to be soluble in most of the organic solvents such as DMSO, DMF, DMAc, m-cresol even at room temperature and few becomes soluble on heating. The degradation temperature of the resultant polymers falls in the ranges from 240°C to 550°C in nitrogen (with only 10% weight loss). Specific heat capacity at 300°C ranges from 1.1899 to 5.2541 J g À1 k À1 . The maximum degradation temperature ranges from 250 to 620°C. T g values of the polyimides ranged from 168 to 254°C.
Polymer Journal, 2006
A fluorine-containing crystalline diamine, , 0-bis[4-(4-amino-2-trifluoromethylphenoxy)phenyl]-1,3-diisopropylbenzene (II), was prepared through nucleophilic substitution reaction of 2-chloro-5-nitrobenzotrifluoride and , 0-bis(4-hydroxyphenyl)-1,3-diisopropyl in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd/C. A series of polyimides (PIs) V a{f were then synthesized from this diamine (II) by polymerizing with various commercially available aromatic dianhydrides (pyromellitic dianhydride (PMDA, III a), 3,3 0 ,4,4 0benzopheno tetracarboxylic dianhydride (BTDA, III b), 3,3 0 ,4,4 0-biphenyltetracarboxylic dianhydride (BPDA, III c), diphenylsulfone-3,3 0 ,4,4 0-tetracarboxylic dianhydride (DSDA, III d), 4,4 0-oxydiphthalic anhydride (ODPA, III e) and 4,4 0hexafluoro isopropylidenediphthalic anhydride (6FDA, III f)) via thermal (H) or chemical (C) imidization methods. The polyimides had inherent viscosities ranging from 0.60 to 0.95 dL/g. Except for the thermal imidization of V b (H), the Vseries polyimides were readily soluble in amide-type solvents, such as N-Methyl-2-pyrrolidone (NMP), N,N-dimethyl acetamide (DMAc), N,N-dimethyl formamide (DMF), and dimethyl sulfoxide (DMSO), and also soluble even in less polar solvents such as m-cresol or pyridine. Most polyimides (film samples) had good tensile strengths of 70 to 110 MPa, elongations at break of 8 to 13% (except for V c , 37%), and initial moduli of 1.7 to 2.0 GPa. The glass-transition temperatures of V-series polyimides were in 182-202 C, and had good thermal stability of 10% weight loss temperatures (491-541 C in nitrogen or 495-537 C in air), and char yields at 800 C in nitrogen ranging 46-61 wt %. Except for V a,b series, the V(H) series had cutoff wavelengths between 364.5 to 399.5 nm and the b à (yellowness index) values ranging from 12.7 to 39.5. The polyimides were found to possess low moisture absorption in the range of 0.19-0.91 wt %.
Polymer Bulletin, 1992
Four new ester group containing diisocyanates, viz., 3,3'-(glutaryldioxy)diphenyl diisocyanate, 4,4'-(glutaryldioxy)diphenyl diisocyanate, 3,3'-(adipoyldioxy)diphenyl diisocyanate, and 4,4'-(adipoyldioxy)diphenyl diisocyanate were synthesized from the corresponding dicarboxylic acids via the Curtius rearrangement reaction. These diisocyanates were polycondensed with pyromellitic dianhydride (PMDA) and benzophenonetetracarboxylic dianhydride (BTDA) in dimethylacetamide to yield eight aliphatic-aromatic polyimides containing ester groups in the backbone with inherent viscosities in the range 0.25-0.70 dL/g. These poly(ester-imide)s were semicrystalline in nature and exhibited no weight loss below 300~ in air.
Preparation and properties of polyimides and polyamide-imides from diisocyanates
Journal of Polymer Science Part A: Polymer Chemistry, 1999
Polyimides of different structures were synthesized by reaction of 1,4phenylene diisocyanate (PPDI) and 1,5-naphthalene diisocyanate (NDI) with pyromellitic dianhydride (PMDA) and 3,3Ј,4,4Ј-benzophenonetetracarboxylic dianhydride (BTDA). Polyamide-imides were also prepared by reaction of PPDI and NDI with trimellitic anhydride. The optimized condition for polymerization reactions were obtained via the study of model compounds. All polymers and model compounds were characterized by conventional methods. Physical properties of polymers, including thermal behavior, thermal stability, solution viscosity, and solubility behavior, were also studied.
Polymer International, 2004
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,Ndimethylacetamide, 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 8C, the temperature at 5% weight loss of 512-540 8C, and the residue at 800 8C 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.
Synthesis and properties of polyimides derived from isomeric biphenyltetracarboxylic dianhydrides
Polymer, 2000
2,2 H ,3,3 H -Biphenyltetracarboxylic dianhydride (i-BPDA) was suggested as a monomer for the synthesis of soluble polyimides with high thermal stability, and an efficient method of its preparation has been developed. Polyimides derived from i-BPDA and aromatic diamines (i.e. 4,4 H -oxydianiline, 2,2 H -bis(trifluoromethyl)benzidine and 9,9 H -fluorenylidene-4,4 H -dianiline) showed high glass transition T g Ͼ 330ЊC and degradation T d5 Ͼ 550ЊC temperatures, and were soluble in organic solvents (i.e. NMP, DMF, g-butyrolacton, CHCl 3 ), although their mechanical properties were inferior to those of polyimides composed of semirigid 3,3 H ,4,4 H -biphenyltetracarboxylic dianhydride (s-BPDA). Random copolymers, derived from i-BPDA and s-BPDA, retained superior mechanical properties of s-BPDA-based polyimides and showed improved solubilities, depending on the i-BPDA content. A regular increase of glass transition temperatures and a decrease of inherent viscosities of copolymers with increasing content of i-BPDA was observed, whereas the dielectric constants and degradation temperatures were found to be independent of the ratios of dianhydride units. ᭧