Soluble polyimides that contain curable internal acetylene groups in the backbone

Takeichi, Tsutomu; Ogura, Satoshi; Takayama, Yuzi

doi:10.1002/pola.1994.080320320

Cited by 15 publications

(6 citation statements)

References 19 publications

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“…The DSC curves of 6FDA-D4A1-400 show that the exotherm almost disappeared and the T g appeared at around 450 • C, indicating that the exotherm in 6FDA-D4A1 originates from the cross-linking reaction induced by the internal acetylene. Compared with reference [44] where the onset temperature of cross-linking reactions was reported to occur at 321-345 • C, the present co-polyimide undergoes cross-linking reactions start at a slightly higher temperature of 370 • C. One of the possible reasons is due to the fact that the present co-polyimides have a lower content of reactive acetylene groups that requires a higher temperature to overcome the energy barrier to initiate the reaction. Another plausible and contributing factor is that the bulky side group of Durene hinders the polymer chain mobility and decreases the possibility of a reaction between polymer chains.…”

Section: Thermally Cross-linked Co-polyimidesmentioning

confidence: 64%

“…Acetylene cross-linking sites situated along the polymer chain should provide a greater degree of rigidification over endcap sites. Takeichi et al have studied cross-linking behavior of internally linked acetylene units to the aromatic rings by preparing polyimide from 4,4 ′ -diaminodiphenylacetylene (p-intA) and 2,2 ′ -bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) [42][43][44]. In order to avoid excessive cross-linking which may result in impractical low gas permeability and poor mechanical properties, a co-polyimide was synthesized that contained 2,3,5,6-tetramethyl-1,4-phenylenediamine (Durene) monomer to dilute the cross-linking sites.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis, cross-linking and carbonization of co-polyimides containing internal acetylene units for gas separation

Xiao

Chung

Guan

et al. 2007

Journal of Membrane Science

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Cross-linkable polyimides containing internal acetylene units have been synthesized by random copolymerization of 6FDA dianhydride, 2,3,5,6-tetramethyl-1,4-phenylenediamine (Durene) and 4,4 ′ -diaminodiphenylacetylene (p-intA) diamine as materials for gas separation. Compared with 6FDA-Durene polyimide, 6FDA-Durene/p-intA co-polyimide shows denser polymer chain packing, which is confirmed by wide-angle X-ray diffraction (WAXD). The thermally treated co-polyimides are insoluble in various solvents and show an increase in T g , indicating the formation of network structures among the polymer chains. Differential scanning calorimetry (DSC) and FT-Raman suggest that cross-linking arises from Diels-Alder cycloaddition between the internally arranged acetylene units along the polymer main chain, resulting in extended conjugated aromatic structures. The thermally cross-linked membranes show enhanced resistance to CO 2 plasticization up to around 5 × 10 6 Pa (700 psi). The rigidified membrane structure provides increased gas selectivity without severely compromising gas permeability. The gas separation performance of carbonized membranes is remarkably superior to those of neat and cross-linked copolyimides because of a large increase in rigidification in the polymer matrix. A Diels-Alder cycloaddition reaction produces a much more rigid and planar conjugated aromatic structure in the polymer chains and results in a higher degree of graphitization during carbonization, which is confirmed by XPS and WAXD. Carbon membranes derived from co-polyimides with more internal acetylene units show much better gas separation performance than those derived from polyimides without internal acetylene units.

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Section: Thermally Cross-linked Co-polyimidesmentioning

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Synthesis, cross-linking and carbonization of co-polyimides containing internal acetylene units for gas separation

Xiao

Chung

Guan

et al. 2007

Journal of Membrane Science

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“…PAA was further in situ one‐step imidized by the azeotropic distillation of toluene to remove water from imide condensation polymerization. The polyimide product could be obtained in solution because of the solubility of 6FDA, which was chosen as a dianhydride to produce the soluble polyimide 10. The soluble products were needed for further reactions with the soluble hyperbranched polyethers.…”

Section: Resultsmentioning

confidence: 99%

Dielectric properties and solubility of multilayer hyperbranched polyimide/polyhedral oligomeric silsesquioxane nanocomposites

Somboonsub

Thongyai

Praserthdam

2009

J of Applied Polymer Sci

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Multilayer hyperbranched polyimide/polyhedral oligomeric silsesquioxane (POSS) nanocomposites were synthesized by the reaction of a bromidehyperbranched polyether/POSS and a main-chain polyimide containing hydroxyl-functional groups. The first layer was formed through the direct reactions of the main-chain hydroxyl groups with monochloroisobutyl polyhedral oligomeric silsesquioxane (POSS-Cl). The second and third layers were prepared by the repeated reactions of bromine ether branches that incorporated POSS-Cl with 3,5-dihydroxybenzyl alcohol. Regardless of the fixed amount of POSS, the higher layers yielded lower dielectric constants. Even when the amount of the POSS loading was reduced 4-fold, the third layer still had the lowest dielectric constants. The lowest dielectric constant of 2.54 was found in the third layer of the hyperbranched polyimide/POSS nanocomposite because of the large free volume and loose polyimide structures. The densities of the hyperbranched polyimide/POSS nanocomposite corresponded to the dielectric constants. The lower the density was, the higher the free volume was and the lower the dielectric constant was. The experimental results indicated that the hyperbranched polyimide/POSS nanocomposite exhibited increased solubility in comparison with pure polyimide.

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“…In the case of TMA/m-intA imidized at 200 • C, the onset of the exotherm appeared at ca 297 • C (figure 2). This onset temperature is rather low for the acetylene-containing aromatic polymers since exotherm onset for the acetylene containing polyimides and also polyamides was about 320 • C [11][12][13][14][15][16]24]. We think that the unsymmetrical structure and hydrogen bonding of poly(amide-imide) are the reasons for the low exothermic temperature.…”

Section: Crosslinking Behaviour Of M-intamentioning

confidence: 89%

“…We have introduced internal acetylene units into the backbone of polyimides [11][12][13][14][15][16][17] and oligoimides [18][19][20][21][22][23], and studied the crosslinking behaviour of the acetylene units and properties of the crosslinked polyimides. Crosslinking of the acetylene units gave polyimides that have high T g and excellent thermal stability.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Properties of Poly(Amide-Imide) Containing Acetylene Units in the Main Chain

Takeichi

Suefuji²,

Zuo

2001

High Performance Polymers

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Poly(amide-imide) containing internal acetylene units in the backbone was prepared from trimellitic anhydride chloride and bis(3-aminophenyl)acetylene in N-methyl-2-pyrrolidone at room temperature, followed by thermal imidization.Differential scanning calorimetry measurements of the poly(amide-imide) showed an exotherm due to the crosslinking reaction of the internal acetylene units. With higher heat treatment, the exotherm shifted to higher temperatures and the amount of the exotherm decreased. The exotherm finally disappeared after 400 • C treatment. Viscoelastic measurements revealed that the crosslinked polymer had a higher glass transition temperature and maintained a storage modulus up to higher temperatures. The thermogravimetric analyses profile showed that the crosslinking of internal acetylene units gave a thermally stable structure.

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Soluble polyimides that contain curable internal acetylene groups in the backbone

Cited by 15 publications

References 19 publications

Synthesis, cross-linking and carbonization of co-polyimides containing internal acetylene units for gas separation

Synthesis, cross-linking and carbonization of co-polyimides containing internal acetylene units for gas separation

Dielectric properties and solubility of multilayer hyperbranched polyimide/polyhedral oligomeric silsesquioxane nanocomposites

Preparation and Properties of Poly(Amide-Imide) Containing Acetylene Units in the Main Chain

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