Investigation of the role of the pyrimidine ring in the main chain of polyamido acids and polyimides. 1. Supermolecular structure of polypyromellitimides based on 2,5-bis(p-aminophenyl)pyrimidine and its carbocyclic analog 4,4?-diaminoterphenyl

Artem'eva, V. N.; Kudryavtsev, V. V.; Nekrasova, E. M.; Sklizkova, V. P.; Baklagina, Yu. G.; Lukasheva, N. V.; Shkurko, O. P.; Borovik, V. P.

doi:10.1007/bf00863810

Cited by 9 publications

(3 citation statements)

References 3 publications

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“…In 1990s, Artem'eva et al published 4 papers and comprehensively studied the role of the PRM ring in the PAA and PI main chains. 38,[41][42][43] They found that (1) the PRM unit facilitated the formation of layered packing structures in the PAA and PI main chain; 41,42 (2) the PRM unit had strong interaction with the imide; 38 (3) the PRM ring greatly reduced the activation energy for the thermal imidization; 43 and (4) the PRM rings could catalyze the resynthesis of the amic acid fragments during the imidization and increase the molecular weight of PI. 43 However, when further increasing the imidized temperature into 350 1C, the tensile strength and modulus dropped down to 860 MPa and 30 GPa, respectively, which might be due to the high temperature induced partially molecular breakage of the ether group on the PI molecule backbones.…”

Section: Mechanical Properties Of Single Electrospun Co-paa and Co-pi...mentioning

confidence: 99%

Single electrospun nanofiber and aligned nanofiber belts from copolyimide containing pyrimidine units

et al. 2015

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Section: Mechanical Properties Of Single Electrospun Co-paa and Co-pi...mentioning

confidence: 99%

Single electrospun nanofiber and aligned nanofiber belts from copolyimide containing pyrimidine units

et al. 2015

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“…The formation of interchain hydrogen bond was accompanied by formation of shear packing, which promoted in-plane orientation of PAA chains. 40,47 This phenomenon may explain why linearity of PMDA/phDBOA was close to that of PMDA/p-PDBOA, but Δn value of the latter was larger than that of former.…”

Section: Basic Characterization On Pi Filmsmentioning

confidence: 91%

High glass transition temperature and ultra‐low thermal expansion coefficient polyimide films containing rigid pyridine and bisbenzoxazole units

Feng

Lin

Jiao

et al. 2023

Journal of Polymer Science

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Polyimide (PI) films with extremely high heat‐resisting and dimensional stability are ideal substrate materials for flexible organic light‐emitting diodes. In this study, three diamines containing rigid bisbenzoxazole structures, 2,2′‐p‐phenylenebis(5‐aminobenzoxazole) (phDBOA), 2,2′‐m‐pyridylenebis(5‐aminobenzoxazole), and 2,2′‐p‐pyridylenebis(5‐aminobenzoxazole) (p‐PDBOA), were polymerized with 3,3′,4,4′‐biphenyl tetracarboxylic dianhydride and pyromellitic dianhydride (PMDA) separately with traditional two‐step approach to prepare a set of PI films. Introduction of bisbenzoxazole improves stiffness of molecular chain, whereas that of pyridine increases in‐plane orientation and molecular chain tend to be densely stacked. Among prepared films, PI‐6 (PMDA/p‐PDBOA) shows the most excellent mechanical properties, with an ultra‐high glass transition temperature of >450°C, an ultra‐low thermal expansion coefficient of <5 ppm K−1 (50–450°C), a tensile strength of 259 MPa, and a modulus of 8.3 GPa. Given these excellent properties, PI‐6 could be applied in flexible display.

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“…This implies that the two N atoms in pyrazine, as good H-bonding acceptors, can make the molecular chains closer in the PAA state, eventually affecting the final PI films. 37,44 Overall, PRZ diamine visibly exhibits a rigid-rod, symmetric, and nearly coplanar backbone, as well as two Hbonding acceptors of pyrazine rings, which are likely to endow the final PI materials with excellent potential thermal and mechanical properties.…”

Section: Stericmentioning

confidence: 99%

Near-Zero Thermal Expansion and High Heat-Resistance Polyimide Films Based on a Symmetric and Rigid Pyrazine Structure

Bao

Lei

et al. 2022

ACS Appl. Polym. Mater.

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Regarding the applications of polyimide (PI) films in emerging flexible devices and precision apparatus, their low coefficient of thermal expansion (CTE), especially near-zero expansion, is an urgent requirement for weakening the internal stress between the organic/ inorganic layers. Other properties of PI films including the high heatresistance and superior toughness are also demanded in actual scenarios. Herein, a set of PI films was developed by copolymerization of 2,5-bis(4aminophenyl)pyrazine (PRZ) into a pyromellitic dianhydride (PMDA)/ 4,4′-oxydianiline (ODA) system. The monocrystal analysis of the PRZ monomer reveals its rigid, symmetric, and nearly coplanar steric structure. Thanks to the synergy and balance of flexible ODA and rigid PRZ units in PI chains, the near-zero expansion, high heat-resistance, and optimal mechanical properties of the PI films are simultaneously achieved. Particularly, the PI film with ODA/PRZ = 4.5/5.5 presents a near-zero CTE of −0.41 ppm/K, high glass transition temperature (T g ) of around 417 °C, superior fracture strength of 191 MPa, and initial modulus of 3.83 GPa. Interestingly, via adjusting the ODA/PRZ ratios, the precise control of CTE values can be realized, enabling the thermal expansion matching of PI films on broad types of device substrates, e.g., Cu (15−17 ppm/K) and Si (3−5 ppm/K).

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Investigation of the role of the pyrimidine ring in the main chain of polyamido acids and polyimides. 1. Supermolecular structure of polypyromellitimides based on 2,5-bis(p-aminophenyl)pyrimidine and its carbocyclic analog 4,4?-diaminoterphenyl

Cited by 9 publications

References 3 publications

Single electrospun nanofiber and aligned nanofiber belts from copolyimide containing pyrimidine units

Single electrospun nanofiber and aligned nanofiber belts from copolyimide containing pyrimidine units

High glass transition temperature and ultra‐low thermal expansion coefficient polyimide films containing rigid pyridine and bisbenzoxazole units

Near-Zero Thermal Expansion and High Heat-Resistance Polyimide Films Based on a Symmetric and Rigid Pyrazine Structure

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