Synthesis and characterization of polyimides from imidazole-blocked 2,5-bis[(n-alkyloxy)methyl]-1,4-benzene diisocyanates and pyromellitic dianhydride

Abstract

From imidazole‐blocked 2,5‐bis[(n‐alkyloxy)methyl]‐1,4‐benzene diisocyanates and pyromellitic dianhydride a series of new rigid‐rod polyimides (Cn‐PY‐PI; n = 4, 6, 8) having linear and flexible (alkyloxy)methyl ((SINGLE BOND)CH2OCnH2n + 1; n = 4, 6, 8) side chains were prepared and characterized and their properties were measured and discussed with regard to effects of side chains. Incorporation of the side chains onto the rigid main chain greatly enhanced the solubility and fusibility of the polymers, and melting point of C8‐PY‐PI was determined to be 277°C. The UV‐VIS absorption behavior was independent of side‐chain length. TGA thermograms revealed a two‐step pyrolysis behavior, in which the side chains split off separately at lower temperatures. X‐ray diffractograms showed that all the polyimides are crystalline at room temperature. Sharp reflections in small‐angle region obviously indicated the presence of a layered crystal structure. © 1996 John Wiley & Sons, Inc.

High performance polyimides for applications in microelectronics and flat panel displays

“…Thus, there still is a big challenge to improve their brittleness and dielectric constant with retaining the high moduli. Attempts to improve such drawbacks with a little sacrifice of the high modulus have been made in two different ways: (i) incorporation of short side groups into the polymer backbone [89][90][91][92][93][94][95][96][97][98][99] and (ii) insertion of proper linkages into the polymer backbone. 6 There are two options in incorporating short side groups into the polymer rod.…”

“…89,[94][95][96][97][98][99] And, some benzidine (BZ) derivatives with short side groups are also available: 2,2'-bis(methyl)benzidine (MEBZ), 2,2'-bis(methoxy)benzidine (MEOBZ), 2,2'-bis (fluoro) benzidine (FBZ), 2,2'-bis(trifluoromethyl)benzidine (CF3BZ), 3,3'-hydroxy-4,4'-diaminobiphenyl (HAB), and o-tolidine (TDI). 90,92,95,135 On the other hand, several research groups 91,93,100-103 have attempted to incorporate short side groups into pyromellitic dianhydride (PMDA).…”

Mechanical and Thermal Properties of Networks Prepared from Reactive Poly(urethane-imide)s and Blocked Polyurethane Prepolymer

“…[13,14] Imidazole-blocked diisocyanates have been used to prepare polyimides. [8] Such a type of reaction of blocked isocyanate differs from the reaction of polyurethane formation, and this may open a new area of application. Intermolecular Diels-Alder reaction of 4-methyl-1,3-phenylenebis(2-furanylcarbamate) with different bismaleimides is reported to give polyimide-polyurethanes.…”

Structure-property relationship of blocked diisocyanates: synthesis of polyimides using imidazole-blocked isocyanates

“…A recent report22 discloses the use of imidazole blocked 2,5‐bis[( n ‐alkyloxy)methyl]‐1,4‐benzene diisocyanates to prepare rigid rod‐like polyimides from the reaction of imidazole‐blocked isocyanate with pyromellitic dianhydride. This type of reaction of imidazole‐blocked isocyanate differs from the reaction of polyurethane formation, and this may open a new area of application.…”