๐”– Bobbio Scriptorium
โœฆ   LIBER   โœฆ

Soluble aromatic polyimides based on 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane: Synthesis and properties

โœ Scribed by D. Likhatchev; C. Gutierrez-Wing; I. Kardash; R. Vera-Graziano


Publisher
John Wiley and Sons
Year
1996
Tongue
English
Weight
804 KB
Volume
59
Category
Article
ISSN
0021-8995

No coin nor oath required. For personal study only.

โœฆ Synopsis


Aromatic polyimides were synthesized from 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (6F-OH diamine) and different aromatic dianhydrides by a one-step hightemperature polycondensation, or by a two-step procedure using either thermal or chemical imidization of poly(amic acids), PAA. The obtained polyimides were compared in terms of their chemical structure, molecular weight, mechanical and thermal properties. The reaction of 6F-OH diamine with different aromatic dianhydrides in amide solvents at room temperature resulted in the formation of PAA with moderate molecular weight (tinh I 0.7 g/ dL). The thermal imidization of these PAAs led to brittle hydroxy polyimides (PI-6F-OH). In contrast, chemical imidization of similar PAAs in acetic anhydride and pyridine brought about flexible self-supporting polyimide films. The FTIR analysis indicated that the latter process was accompanied by an esterification of the OH groups in the diamine moieties, resulting in the formation of the polymers with side acetate groups (PI-6F-Ac). The high molecular weight hydroxy polyimides, suitable for preparation of films with good tensile properties, were synthesized by a one-step high-temperature polycondensation in phenolic solvents. All obtained polyimides were well soluble in common organic solvents. The highest solubility was observed for PI-6F-Ac. It was found by means of FTIR and TGA that the polyimides with the R group (R = OH or acetate) in orto position to the nitrogen atom in the diamine moiety underwent a rearrangement to benzoxazoles above 300ยฐC. The starting temperature and conversion of this rearrangement reaction were controlled by the type of R group. The imide-to-benzoxazole rearrangement shifted to lower temperatures, and higher conversion was encountered for the polyimides with side acetate group, PI-6F-Ac, obtained by chemical imidization.


๐Ÿ“œ SIMILAR VOLUMES


Preparation and properties of soluble ar
โœ Dong-Ho Lee; Seung-Young Koo; Dae-Yong Kim; Heung-Jin Choi ๐Ÿ“‚ Article ๐Ÿ“… 2000 ๐Ÿ› John Wiley and Sons ๐ŸŒ English โš– 190 KB ๐Ÿ‘ 2 views

Aromatic polyetherimides were synthesized from a fluorine containing aromatic carboxylic acid dianhydride, 2,2-bis [4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride (6F-BABPA) and five typical aromatic diamines including 1,1-bis(4-aminophenyl)-1-phenyl-2,2,2-trifluoroethane (3F-DAM) by t

Synthesis and properties of soluble arom
โœ Guey-Sheng Liou ๐Ÿ“‚ Article ๐Ÿ“… 1998 ๐Ÿ› John Wiley and Sons ๐ŸŒ English โš– 152 KB ๐Ÿ‘ 1 views

Aromatic tetracarboxylic dianhydride having crank and twisted noncoplanar structure, 2,2 -bis(3,4-dicarboxyphenoxy)-1,1 -binaphthyl dianhydride, was synthesized by the reaction of 4-nitrophthalonitrile with 2,2 -dihydroxy-1,1 -binaphthyl, followed by alkaline hydrolysis of the intermediate bis(ether