Softening and Melting Temperatures of Aromatic Polyimides

Bessonov, M.I.; Кузнецов, Н. П.

doi:10.1007/978-1-4615-7637-2_26

Cited by 8 publications

(4 citation statements)

References 5 publications

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“…It is understandable that the rodlike segments of s-BPDA/PDA induces strong interchain interactions and consequently forms crystallike order . However, the higher T g of a-BPDA/PDA is not readily explained from a general consideration that the introduction of a kink point, e.g., −O−, −S−, −CH 2 −, −SO 2 −, −CO−, into the repeating unit of a rigid PI main chain should decrease the T g 's significantly . We discuss this inconsistency later.…”

Section: Resultsmentioning

confidence: 95%

“…The higher T g 's of a-BPDA-based PIs seem to be contradictory to many results for the structure− T g relationship in PI systems. Bessonov et al demonstrated that the introduction of the bent points such as ether linkage into PI chains, especially into the diimide portions, reduces markedly the T g . They classified a variety of aromatic PIs into four groups based on the position and number of the bent points in the structure.…”

Section: Resultsmentioning

confidence: 99%

“…(a) Model Compound Approach. An empirical relation, T m ≈ 1.3 T g (in kelvin), is known for flexible PI systems containing the ether linkages. According to this relation, it is expected from the comparison of the T g 's of a-BPDA/PDA and s-BPDA/PDA that the former has a higher T m than the latter.…”

Section: Resultsmentioning

confidence: 99%

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Structure and Properties of Novel Asymmetric Biphenyl Type Polyimides. Homo- and Copolymers and Blends

et al. 1998

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Asymmetric biphenyl type polyimides (PI) were prepared by thermal imidization of polyamic acids (PAA) derived from 2,3,3‘,4‘-biphenyltetracarboxylic dianhydride (a-BPDA) and p-phenylenediamine (PDA) or 4,4‘-oxydianiline (ODA). The dynamic mechanical properties of these PIs were compared with those of the isomeric PIs derived from symmetric 3,4,3‘,4‘-biphenyltetracarboxylic dianhydride (s-BPDA). a-BPDA/PDA polyimide has a considerably bent chain structure compared to semirigid s-BPDA/PDA. Nevertheless, the a-BPDA/PDA film annealed at 350 °C showed a higher T g than the s-BPDA/PDA film prepared under the same conditions. When these PIs were annealed at 400 °C, a-BPDA/PDA exhibited an abrupt E‘ decrease at the T g (=410 °C) as well as the counterpart annealed at 350 °C, whereas s-BPDA/PDA showed no distinct T g in the E‘ curve. Similar annealing effects were also observed for the ODA systems. The unexpectedly higher T g's of a-BPDA-based PIs could be explained in terms of the more restricted conformational change through the crank shaft-like motion. The difference between the extents of the E‘ decrease at the T g for a- and s-BPDA-based PIs is attributed to the difference of the intensity of intermolecular interactions. The blends of s-BPDA/PDA with a-BPDA-based PI (80/20) and the corresponding copolyimide improved the insufficient thermal processability of homo s-BPDA/PDA without causing a decrease in T g. The results revealed that, for semirigid s-BPDA/PDA, a-BPDA-based PIs are better matrix polymers than s-BPDA/ODA.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 99%

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Structure and Properties of Novel Asymmetric Biphenyl Type Polyimides. Homo- and Copolymers and Blends

et al. 1998

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“…Values of T g range from above 300 up to about 410°C, depending on the structure (81,82). Most are thermoset in industrial applications; some experimental ones have melting temperatures above 400°C (83). In addition to excellent high temperature behavior, they are physically strong because of strong intermolecular forces between the polymer chains (84).…”

Section: Characteristic Polymeric Behaviormentioning

confidence: 99%

Mechanical Behavior of Polymers

Sperling

2005

Introduction to Physical Polymer Science

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Poly(phenylquinoxaline‐imide‐amide)s containing perfluoroisopropylidene units

Hamciuc¹,

Brumă²,

Mercer³

et al. 1995

Angew. Makromol. Chem.

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Poly(pheny1quinoxaline-imide-amide)s have been synthesized by solution polycondensation of aromatic diamines containing preformed phenylquinoxaline units with diacid dichlorides incorporating preformed imide rings and perfluoroisopropylidene units. These polymers show high thermal stability; they decompose above 400°C and have glass transition temperatures in the 225 -290 " C range. Comparison of these compounds with related heterocyclic polymers leads to the conclusion that the decomposition of the former ones begins with the destruction of amide groups. Films prepared from polymer solutions showed good electrical insulating properties, comparable to those of a standard film (Film H). The highest quality of these poly(pheny1quinoxaline-imide-amide)s is their remarkable solubility in polar aprotic solvents, which is very important for practical applications. ZUSAMMENFASSUNG:Poly(phenylchinoxa1in-imid-amid)e wurden durch Polykondensation von aromatischen Diaminen mit Dicarbonsiuredichloriden hergestellt, wobei die Diamine Phenylchinoxalin-Einheiten und die Dichloride lmidringe und Perfluorpropylideneinheiten enthielten. Diese Polymeren besitzen eine hohe thermische Stabilitat; ihre Glasiibergangstemperaturen liegen im Bereich 225 -290 "C, und sie zersetzen sich oberhalb 400 "C. Ein Vergleich mit ahnlichen heterocyclischen Polymeren 1iiBt den SchluB zu, daf3 der Abbau mit der Zersetzung von Amidgruppen beginnt. Aus U s u n g gegossene Filme der Polymeren weisen gute elektrische Isolationseigenschaften auf, Bhnlich denen eines Standardfilms (Film H). Ihre hervorragendste Eigenschaft ist jedoch ihre bemerkenswerte Loslichkeit in polaren aprotischen Ldsungsmitteln, was fur ihre praktische Anwendung von Bedeutung ist.

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Softening and Melting Temperatures of Aromatic Polyimides

Cited by 8 publications

References 5 publications

Structure and Properties of Novel Asymmetric Biphenyl Type Polyimides. Homo- and Copolymers and Blends

Structure and Properties of Novel Asymmetric Biphenyl Type Polyimides. Homo- and Copolymers and Blends

Mechanical Behavior of Polymers

Poly(phenylquinoxaline‐imide‐amide)s containing perfluoroisopropylidene units

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