Synthesis and characterization of fluorinated polybenzoxazoles via solution cyclization techniques

Joseph, William; Abed, J. C.; Merçier, Régis; McGrath, James E.

doi:10.1016/0032-3861(94)90662-9

Cited by 40 publications

(33 citation statements)

References 14 publications

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“…They are widely used in high-performance applications, such as buffer coatings and interlayer dielectric materials in the semiconductor industry. Moreover, they are also used for matrix resins, high modulus fibers, and structural adhesives in the aerospace industry [1][2][3][4][5][6][7]. The synthesis of poly(imidebenzoxazole)s to combine the advantages of both is expected, which has been reported in a few articles and patents [8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

The properties, morphology and structure of BPDA/ PPD/ BOA polyimide fibers

Huang

Gao²,

et al. 2012

E-Polymers

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A family of random copoly(amic acid)s (coPAAs) containing the 2-(4-aminophenyl)-5-aminobenzoxazole (BOA) moiety were synthesized in DMAc, followed by dry-jet wet spinning process into as-spun PAA fibers. The modified polyimide (PI) fibers were obtained from PAA fibers after imidized and drawn in a furnace. The mechanical properties of fibers were improved by incorporating BOA into BPDA/PPD backbone. SEM photo showed that the cross-section of each stage fibers was round and voids free. Besides, the "skin-core" and microfibrillar structure were not observed. The thermal properties of PI fibers were also investigated. The results showed that the PI fibers owned excellent thermal stability, moreover, the dimensional stability and the microphase separation of fibers were improved by heat-drawn stage. The T g were found to be around 290℃ by TMA and DMA. The X-ray (WAXD and SAXS) experiments indicated that the longitudinal stacks, the molecular orientation and the structural homogeneity of PI fiber were improved in the preparation process of fibers.

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Section: Introductionmentioning

confidence: 99%

The properties, morphology and structure of BPDA/ PPD/ BOA polyimide fibers

Huang

Gao²,

et al. 2012

E-Polymers

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“…The first is a two-step method that involves the polycondensation of bis(o-aminophenol)s or their trimethylsilylated derivatives with aromatic dicarboxylic acid chlorides giving precursor poly(o-hydroxy-amide)s, followed by thermal solid-state or solution cyclodehydration yielding PBOs. [3][4][5][6][7][8] The second is a one-step process directly producing PBOs by the melt polycondensation of bis(o-aminophenol)s with aromatic dicarboxylic acid diphenyl esters 9 and by the solution polycondensation with aromatic dicarboxylic acids in acidic media like polyphosphoric acid. 10 -14 Still another facile method has been known for the preparation of PBOs, that is, the one-step polycondensation method from nitrile-bearing o-aminophenols and from monomer pairs of bis(o-amoinophenol)s and dinitriles.…”

Section: Introductionmentioning

confidence: 99%

Facile synthesis of aromatic polybenzoxazoles from monomers havingo-aminophenol and nitrile functions

Itoya¹,

Sawada²,

Kakimoto³

et al. 1999

J. Polym. Sci. A Polym. Chem.

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“…The processability or solubility of these polymers could be improved by the introduction of the flexible units or bulky pendant groups to the main chain. [8][9][10][11] Nowadays, It is well known that dendritic macromolecules such as dendrimers or hyperbranched polymers have unusual properties compared to their linear analogues like as better solubility, lower solution viscosity and higher functionality. [12][13][14][15][16] Although dendrimers have unique architecture, their preparation in- † To whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characteristics of Hyperbranched Polybenzoxazoles via Poly(o-hydroxyamide) Precursors

Hong

Jikei

Kakimoto

2003

Polym J

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ABSTRACT:The novel AB 2 and A 2 B type monomers for hyperbranched polybenzoxazoles (HBPBOs) containing one (or two) hydroxy amine and two (or one) carboxylic acid groups in the aromatic backbones were prepared starting from 5-methoxyresorcinol and 4-fluorobenzonitrile for AB 2 and 3,5-dihydroxybenzoic acid and 3-fluoro-6-nitrophenol for A 2 B monomer. Hyperbranched poly(o-hydroxyamide)s (HBPHAs) as precursors of HBPBOs were synthesized by self-polycondensation of the AB x type monomers in the presence of (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonic acid diphenyl ester (DBOP) as a condensing agent at room temperature. The terminal groups of free carboxylic acid or amine were chemically modified with 2-amino-4-tert-butylphenol or 3,5-dimethylbenzoic acid. End-capped HBPHAs had good solubility in aprotic solvents and tetrahydrofuran (THF) having the weight average molecular weight (M w ) in the range of 27000-131000. The conversion of HBPHA to HBPBO was carried out by thermal and chemical cyclization methods. HBPBOs prepared by chemical cyclization of HBPHAs in polyphosphoric acid (PPA) were soluble in aprotic solvents such as N-methyl-2-pyrrolidinone (NMP), N,N-Dimethylacetamide (DMAc), Dimethyl Formamine (DMF), and THF, whereas thermally cyclized ones were insoluble in any organic solvents.1 H NMR and IR analyses indicated that the chemical cyclization proceeded quantitatively. The weight-average molecular weights (M w ) of soluble HBPBOs were found to be 23000-97000 by gel permeation chromatography (GPC) measurement with standard polystyrene calibration. Both of HBPBOs prepared by thermal and chemical cyclization methods showed excellent thermal stability having the 10 wt% weight loss (T 10 ) in the range of 488-537• C under nitrogen.KEY WORDS Polybenzoxazoles / Hyperbranched Polymer / Cyclodehydration / Poly(o-hydroxyamide)s / One-pot Polymerization / AB 2 Monomer / The aliphatic polybenzoxazoles (PBOs) were first synthesized through the melt polycondensation of 3,3 -diaminobenzidine tetrahydrochloride and sebacic acid by Brinker et al. in 1959. 1 Six years later, linear aromatic polybenzoxazoles (PBOs) were first reported by Imai et al. 2 and have since been under widespread investigation. For a few decades, both of AA-BB and AB type monomer systems have been studied in the synthesis of linear polybenzoxazoles having good thermal and mechanical properties. 3-7 Fibers prepared from this polymer have superior tensile strength and flame retardance. PBO fibers were used in high-performance composites and comfortable protective garments. However, in spite of these attractive properties, their application has been somewhat limited since their poor processability. The processability or solubility of these polymers could be improved by the introduction of the flexible units or bulky pendant groups to the main chain. [8][9][10][11] Nowadays, It is well known that dendritic macromolecules such as dendrimers or hyperbranched polymers have unusual properties compared to their linear analogues like as better solubility...

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Synthesis and characterization of fluorinated polybenzoxazoles via solution cyclization techniques

Cited by 40 publications

References 14 publications

The properties, morphology and structure of BPDA/ PPD/ BOA polyimide fibers

The properties, morphology and structure of BPDA/ PPD/ BOA polyimide fibers

Facile synthesis of aromatic polybenzoxazoles from monomers havingo-aminophenol and nitrile functions

Synthesis and Characteristics of Hyperbranched Polybenzoxazoles via Poly(o-hydroxyamide) Precursors

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