Structure and Properties of Novel Asymmetric Biphenyl Type Polyimides.

Hasegawa, Masatoshi; Sensui, Nobuyuki; Shindo, Yoichi; Yokota, Rikio

doi:10.2494/photopolymer.9.367

Cited by 12 publications

(7 citation statements)

References 8 publications

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“…In contrast to this trend, we have previously reported that PI films derived from an isomer of s-BPDA, namely 2,3,3 1 ,4 1 -BPDA, with a bent/distorted structure, (asymmetric BPDA or a-BPDA, table 1) always led to higher T g values than the corresponding PIs from s-BPDA with the same diamines [8,11]. The increased T g values can be explained from the suppressed internal rotation around the biphenyl linkage in the a-biphenyldiimide (a-BPDI) moiety.…”

Section: Introductionmentioning

confidence: 68%

Isomeric Biphenyl Polyimides. (I) Chemical Structure-property Relationships

Chen¹,

Yokota

Hasegawa

et al. 2005

High Performance Polymers

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A series of polyimides (PIs) were prepared from three biphenyltetracarboxylic dianhydrides (BPDA) isomers, i.e., 3,3′,4,4′-BPDA (s-BPDA), 2,3,3′,4′-BPDA (a-BPDA), and 2,2′',3,3′'-BPDA (iBPDA) with various diamines through the conventional two step process. Polymerization reactivity, solubility, and dynamic mechanical properties (T g, softening behavior, and storage modulus at glassy state) were compared between PIs derived from these BPDA isomers and para/meta diamine isomers. The solubility in NMP increased as follows: i-BPDA-PI > a-BPDA-PI > s-BPDA-PI. The order is attributed to semi-crystalline and fully amorphous morphologies of s-BPDA-PI and other isomeric BPDA-PIs, respectively. The use of meta-diamines lowered the T g whereas the use of bent/distorted BPDA isomers enhanced the T g (s-BPDA-PI < a-BPDA-PI < i-BPDA-PI). The BPDA isomer effect on T g is based on the difficulty of obtaining internal rotation around the biphenyl linkages. The width of the DMA rubbery plateau region decreased in the order of i-BPDA < a-BPDA-PI < s-BPDA-PI, depending on the crystallinity and the extent of chain entanglement. In a-BPDA and i-BPDA-PI systems, PIs from metadiamines led to higher modulus than the corresponding PIs from para-diamines.

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Section: Introductionmentioning

confidence: 68%

Isomeric Biphenyl Polyimides. (I) Chemical Structure-property Relationships

Chen¹,

Yokota

Hasegawa

et al. 2005

High Performance Polymers

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“…Ultraviolet−visible (UV−vis) absorption spectra of biphenyl derivatives provide qualitative information on the biphenyl conformation in solution; when ω ≈ 90°, the absorption spectrum becomes similar to the 2-fold spectrum of the corresponding monomeric unit (phenyl derivatives) owing to the sterically inhibited conjugation, but a peak red shift and enhancement of the band intensity become prominent as it approaches coplanar structure. , According to this criterion, we compared M(a-BPDA/CHA) with M(PA/CHA) as its monomeric derivatives, since the corresponding aniline (AN)-derived model compounds do not show a distinct peak of the (π,π*) band. , Figure shows the absorption spectra of these model compounds in solution, together with M(s-BPDA/CHA). M(a-BPDA/CHA) exhibited a stronger and red-shifted spectrum compared to the 2-fold of the M(PA/CHA) spectrum, suggesting qualitatively that a-BPDA has a ω lower than 90°.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, the local ordering, which depends strongly on the manufacturing conditions, was observed by means of various techniques, and the role of the ordered structures for the properties was discussed. − The most extensively reported results deal with the Kapton type polyimide, PMDA/ODA, derived from pyromellitic dianhydride (PMDA) and ODA. So far, we have focused Upilex type PIs, i.e., s-BPDA/PDA and s-BPDA/ODA, and reported the improved mechanical properties of the homopolymers , and their composites, , the spontaneous molecular orientation phenomenon induced by thermal imidization, , and local ordered structure formation. , However, there are few reports on asymmetric biphenyl type PIs, since this monomer is not commercially available. − The present paper describes the properties of the new type of PIs derived from a-BPDA and discusses the comparison with the corresponding s-BPDA-based PIs. We focus here on the dynamic mechanical properties of a-BPDA-based homopolyimides and, in addition, the copolyimides and the blends containing a small content of a-BPDA component.…”

Section: Introductionmentioning

confidence: 99%

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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“…[23][24][25] Tensile properties of typical PIs are given in Table V. Typically found were tensile strengths at break of ca.…”

Section: Properties Of Polymersmentioning

confidence: 99%

Preparation of polyimides derived from biphenyltetracarboxylic dianhydrides and aromatic diamines bearing alkylene spacers

Shiotani

Kohda

1999

J. Appl. Polym. Sci.

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Four series of aromatic polyimides (PIs V-VIII) composed of biphenyltetracarboxylic dianhydrides (BPDAs) and aromatic diamines bearing alkylene spacers were prepared by two methods. Most polymers could be readily prepared in a one-step method for the combination of a-BPDA with ␣,-bis(3-aminophenoxy)alkanes, a-BPDA with ␣,-bis(4-aminophenoxy)alkanes, and s-BPDA with ␣,-bis(3-aminophenoxy)alkanes. However, the polymerization of s-BPDA with ␣,-bis(4-aminophenoxy)alkanes gave powders. On the other hand, all four monomer combinations afforded the desired polyamic acid solution in a two-step method. These polymer solutions could be cast into tough and flexible films, which were characterized by their inherent viscosity, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical spectrometry measurements. The glass transition temperatures (T g s) of the polymers were in the range of 110 -240°C, but they were not clearly defined for PIs VIII and VI. The 5% weight loss temperatures were around 450°C for all prepared PIs. For PI VIII an "odd-even" behavior of the tensile properties of the films was detected, corresponding to the reported behavior of the melting temperatures.

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Structure and Properties of Novel Asymmetric Biphenyl Type Polyimides.

Cited by 12 publications

References 8 publications

Isomeric Biphenyl Polyimides. (I) Chemical Structure-property Relationships

Isomeric Biphenyl Polyimides. (I) Chemical Structure-property Relationships

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

Preparation of polyimides derived from biphenyltetracarboxylic dianhydrides and aromatic diamines bearing alkylene spacers

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