POLYIMIDES, POLYQUINOLINES AND POLYQUINOXALINES: T<sub>g</sub>-STRUCTURE RELATIONSHIPS

Lee, Chung J.

doi:10.1080/07366578908050889

Cited by 40 publications

(8 citation statements)

References 49 publications

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“…The T g of the PIs decreased in the order TDA−3SDEA ≈ ODA− 3SDEA > SEDA−3SDEA > TEDA−3SDEA, which coincides with the order of inherent viscosities (η) of the PAA solutions (TDA−3SDEA > ODA−3SDEA > TEDA−3SDEA > SEDA− 3SDEA, Table 1). Lee 53 reported that the T g of semirigid polymers is essentially a function of the chain rigidity/ flexibility of the repeating units and of van der Waals forces and can be explained without considering particular intermolecular interactions such as charge-transfer or dipolar carbonyl−carbonyl attractions.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Synergistic Effect of Sulfur and Chalcogen Atoms on the Enhanced Refractive Indices of Polyimides in the Visible and Near-Infrared Regions

Kim

Goh

et al. 2019

Macromolecules

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To develop thermally stable optical polymers for visible and near-infrared sensor applications, a series of sulfur-containing polyimides (PIs) with chalcogen atoms were successfully synthesized via conventional two-step polycondensation of 4,4′-[p-thiobis(phenylenesulfanyl)]diphthalic anhydride (3SDEA) with four diamines: 4,4′-oxidianiline (ODA), 4,4′-thiodianiline (TDA), 4,4′-selenodianiline (SEDA), and 4,4′-tellurodianiline (TEDA). Because of the large atomic polarizabilities of the sulfur, selenium, and tellurium atoms, the resultant PIs exhibited significantly high refractive indices in the 1.738–1.778 range at 637 nm along with a transmittance >90% at 650–1500 nm. In addition, the PIs exhibited good thermal stability, with high thermal decomposition and glass transition temperatures (T d5% > 390 °C and T g = 183–217 °C, respectively). Owing to the good affinity of SEDA–3SDEA for TiO2 nanoparticles, a nanocomposite film with a 3.0 wt % loading of TiO2 nanoparticles exhibited a refractive index of 1.774 at 637 nm.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Synergistic Effect of Sulfur and Chalcogen Atoms on the Enhanced Refractive Indices of Polyimides in the Visible and Near-Infrared Regions

Kim

Goh

et al. 2019

Macromolecules

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“…If we compare with other reported polyimides based on the same BTDA, BPDA and PMDA dianhydrides, but different TPA-based diamines, it is quite obvious that the pendant 1,3,4-oxadiazole cycle in our polyimides disturbs the chain–chain interactions and induces an internal plasticization effect, thus lowering the overall T g values. Among the chain–chain interactions, charge transfer complex (CTC) formation and the so called “preferred layer packing” has the most important influence over the thermal behavior of the polymers. In our study, how the structural difference of the dianhydride core can modulate the T g is discussed.…”

Section: Results and Discussionmentioning

confidence: 99%

“…In our study, how the structural difference of the dianhydride core can modulate the T g is discussed. According to ref , the formation of CTC between dianhydride and diamine segments has a high impact on the enhancement of the physical forces between polymer chains. Therefore, the proposed CTC formation should be the main cause for the high T g of polyimides.…”

Section: Results and Discussionmentioning

confidence: 99%

n-Type Polyimides with 1,3,4-Oxadiazole-Substituted Triphenylamine Units—An Innovative Structural Approach

Bejan¹,

Constantin²,

Damaceanu³

2019

J. Phys. Chem. C

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A novel aromatic diamine containing 1,3,4-oxadiazole-substituted triphenylamine (TPA) was successfully synthesized and structurally characterized. Based on this, a series of three aromatic polyimides with high thermal stability were prepared and processed in thin coatings with a grain-like morphology. Their ability to form a dual intramolecular charge transfer complex between TPA and 1,3,4-oxadiazole in the side chain and TPA and phthalimide in the main chain was proven. Both the optical effects and electronic properties were found to be modulated by the competing electron-withdrawing character of 1,3,4-oxadiazole/imide units. The electrochemical investigation suggested their n-type redox capability and electron transporting characteristics, a statement supported by current–voltage measurements of some indium tin oxide/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate/polyimide/eGaIn prototype devices. Thereby, the present polyimides enable the pathway toward alternative n-type materials currently used in optoelectronics devices.

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“…The decrease in the value of T g in the case of PI-2 is mainly because of the carbonyl bridging group present in the polymeric chain network, which in turn reduces the charge-transfer complex formation resulting in less rigid and more flexible PIs than PI-1, PI-3, and PI-4. 23 The planarity associated with electron affinity influences the value of T g . Thus, two factors are also responsible for lowering the value of T g for PI-2, whose electron affinity is found to be 1.9 eV, whereas the other two PIs with PI-3 and PI-4 skeletons were found to show higher values of T g , that is, 256 C and 244 C, respectively.…”

Section: Differential Scanning Calorimetrymentioning

confidence: 99%

Synthesis of soluble polyimides based on ether-linked cyclohexyldiamine and their ultraviolet shielding behavior

Revathi

Prabunathan

Devaraju

et al. 2014

High Performance Polymers

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A series of polyimides (PIs) based on ether-linked cyclohexyldiamine were prepared using pyromellitic dianhydride (PI-1), benzophenone dianhydride (PI-2), naphthalene dianhydride (PI-3), and perylene dianhydride (PI-4) in 1-methyl-2-pyrrolidone (NMP) medium to obtain respective polyamic acids and are subsequently converted into PIs through thermal imidization. The resulting PIs were characterized by Fourier transform infrared, X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, and impedance analyses. In addition, the ultraviolet (UV) shielding ability of PIs was also studied and discussed. The vibrational analysis confirms the imidization, and the XRD profile indicates the amorphous nature of the resulting PIs. The PIs synthesized in the present work exhibit good solubility in organic solvents such as NMP, dimethylformamide (DMF), and dimethyl sulfoxide (DMSO). The PI-4-based imide possesses very good solubility with the highest glass transition temperature value of 256°C, highest char yield of 50.16%, highest dielectric constant of 3.9 and higher UV shielding performance of 89% than those of other PIs. Further, the good solubility also makes them useful for coating applications in aerospace and liquid crystal displays.

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POLYIMIDES, POLYQUINOLINES AND POLYQUINOXALINES: T_g-STRUCTURE RELATIONSHIPS

Cited by 40 publications

References 49 publications

Synergistic Effect of Sulfur and Chalcogen Atoms on the Enhanced Refractive Indices of Polyimides in the Visible and Near-Infrared Regions

Synergistic Effect of Sulfur and Chalcogen Atoms on the Enhanced Refractive Indices of Polyimides in the Visible and Near-Infrared Regions

n-Type Polyimides with 1,3,4-Oxadiazole-Substituted Triphenylamine Units—An Innovative Structural Approach

Synthesis of soluble polyimides based on ether-linked cyclohexyldiamine and their ultraviolet shielding behavior

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POLYIMIDES, POLYQUINOLINES AND POLYQUINOXALINES: Tg-STRUCTURE RELATIONSHIPS

Cited by 40 publications

References 49 publications

Synergistic Effect of Sulfur and Chalcogen Atoms on the Enhanced Refractive Indices of Polyimides in the Visible and Near-Infrared Regions

Synergistic Effect of Sulfur and Chalcogen Atoms on the Enhanced Refractive Indices of Polyimides in the Visible and Near-Infrared Regions

n-Type Polyimides with 1,3,4-Oxadiazole-Substituted Triphenylamine Units—An Innovative Structural Approach

Synthesis of soluble polyimides based on ether-linked cyclohexyldiamine and their ultraviolet shielding behavior

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Product

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POLYIMIDES, POLYQUINOLINES AND POLYQUINOXALINES: T_g-STRUCTURE RELATIONSHIPS