4,4 - diphthalic anhydride

Of course, this re-equilibration behavior of two homopoly(amic acids) can be eliminated if one of the components does not exhibit this back reaction. Recombination of different fragments is not possible and stable polyimide precursor blends are accessable [119]. For example, combining a relatively flexible poly(amic acid), hexafluoroisopropylidene diphthalic anhydride (6F)/2,2-bis(4-aminophenoxy-4 -phenyl) propane (BDAF), with a rigid poly(amic alkyl ester), PMDA/p-phenylene diamine (PDA), produced microphase separated polyimide blends as can be interred by the persistence of the... 

Fig. 38. Linear polyimide and bisnadimide obtained with isophthaloyl diphthalic anhydride and raefa-phenylenediamine...

Hexafluoroisopropylidene dianiline was dissolved in DMAc and then treated with the dropwise addition of 4,4 -hexafluoroisopropylidene diphthalic anhydride at ambient temperature. The 20 to 25 wt% solution was next stirred 6 to 8 hours until high molecular polyamic acids were formed. The mixture was treated with a large excess of triethylamine and acetic anhydride and dehydrated by heating to 50°C for 2 to 3 hours and at 100°C to 110° C for 10 to 20 minutes then cooled to ambient temperature. The viscous solution was slowly poured into methanol, and the precipitate was homogenized in a blender. It was then filtered and washed several times with fresh methanol. The material was dried for 12 hours at ambient temperature and 24 hours under vacuum at 250°C, and the product was isolated. 

Selective polyimide membranes, (I), for helium, carbon dioxide, and oxygen were previously prepared by the author [1] by condensing 4,4 -(hexafluoro-isopropylidene) diphthalic anhydride with a 3 2 ratio of 2,4,6-trimethyl-1,3-phenylene diamine and diamino benzoic acid, respectively. 

Soluble polyimide prepared by reaction of 4,4 -hexanuoroisopropylidene diphthalic anhydride (6F) with 3,5-diaminobenzoic acid. 

From the same class of light sensitive and heat resistant polymers, poly[4,4 -hexafluoro-isopropylidene)-diphthalic anhydride-a/f-acridine yellow G], HCI is given as another example. The structure of this polymer is shown below ... 

Figure 13.4.2. Variation of weight % loss forpoly[4,4 -hexafluoro-isopropylidene)-diphthalic anhydride-alt-acridine yellow G] HCI in a TGA experiment at a heating rate of 10P C/min.

The TGA curve indicates a complex decomposition process. The Py-GC/MS result for poly[4,4 -hexafluoro-isopropylidene)-diphthalic anhydride-aff-acridine yellow G] HCI is given in Figure 13.4.3. This is a light sensitive polymer (X max. 273 nm) but also with high heat resistance, and the pyrolysis was performed at 850 C in He. Other conditions were kept similar to those for other examples previously described (see Table 4.2.2). The separation was done on a Carbowax column. The peak identification was done using MS spectral library searches only and is given in Table 13.4.4. 

Figure 13.4.3. Pyrogram from Py-GC/MS analysis of poly[4,4 -hexafluoro-isopropylidene)diphthalic anhydride-alt-acridine yellow G] HCI. Pyrolysis done on 0.4 mg material at 85(f C in He, with the separation on a Carbowax type column.

Finally, two Al-neutralized copolyimides from (4,4 -hexafluoroisopropylidene) diphthalic anhydride, (4,4 -hexafluoroisopropylidene) dianiline, and 3,5-diaminobenzoic acid exhibit a variety of aggregate shapes and sizes that have not been previously observed or even postulated. Scanning TEM shows Al-rich aggregates in both copolymers, but the aggregate size and shape distributions in the ionomer with a high ionic fraction are much more heterogenous than in the ionomer with a lower ionic fraction. This is despite... 

Soluble polyimide prepared by reaction of 4,4 -hexafluoroisopropylidene diphthalic anhydride (6F) with 3,5-diaminobenzoic acid. b Soluble polyimide prepared by reaction of (6F) with 1,5-diaminonaphthalene. c Soluble polyimide prepared by reaction of (6 F) with 1,4-diaminobenzene. d Poly(para-xylylene) Union Carbide Reg. trademark. e Dupont 100 CA-43. f Union Carbide Sulfone 47. 

MAJOR USES Manufacture of diphthalic anhydride, phthalic anhydride, phthalonitrile, benzoic acid, ethyl benzene, high performance polymers, plasitcizers, alkyd resins, glass reinforced polyesters, dyes, insecticides and motor fuels. 

Sulfonated polyimides (sPI) are another type of ionomers that have been prepared [5] by copolymerization of 4,4 -diamino-biphenyl 2,2 -disulphonic acid (BDSA), 4,4 -oxydianiline (ODA), and naphtalenic or phthalic anhydrides. Polyimide structures based on six-membered rings derived from naphtalenics anhydrides, such as 1,4,5,8-naphtalene tetracarboxylic dianhydride (NTDA), shown in Fig. 6.8, are more hydrolitically stable than the five-membered rings basedoxy-diphthalic anhydrides (ODPA). 

Sulfonated PI membranes have been synthesized by the thermal imidization with monomers of 4,4L(hexafluoroisopropylidene)diphthalic anhydride, 4,4Ldiaminodiphenyl ether-2,2 -disulfonic acid, and 3,3Ldiaminochalcone [60]. Chalcone is basically photosensitive and is introduced into the backbone of the copolymers. The resulting copolymer in aqueous electrolyte can be photocrosslinked. From these sulfonated materials, polymer membranes have been prepared by solution casting and eventual thermal imidization. 

Intrinsically microporous Pis have been prepared from 2,2 -diamino-l,l -binaphthalene or 4,4 -(9-fluorenylidene)dianiline. As anhydrides pyromel-litic dianhydride, 3,3, 4,4 -biphenyltetracarboxylic dianhydride, 4,4 -oxydiphthalic anhydride, and 4,4 -(hexafluoroisopropylidene)diphthalic anhydride were used [81]. 

Poly(imide-siloxane)s copolymers have been prepared by the reaction of 4,4 -(4,4 -isopropylidene-diphenoxy)bis(phthalic anhydride), 4,4 -oxydiani-line, and an amino-propyl terminated poly(dimethyl-siloxane) [12]. The polymers exhibit a good solubility in various organic solvents. In addition, 4,4 -(hexafluoroisopropylidene)diphthalic anhydride was used as hard block segment [84]. 

The thermal rearrangement of a-hydroxyl-PI membranes improves the gas permselectivity properties in comparison to a neat PI. By intro-dueing segments within the polymer that do not undergo thermal rearrangement, the gas separation properties of the thermally rearranged membrane can be modified. PI copolymers based on 4,4 -hexafluoroisopropylidene diphthalic anhydride and diamines 3,3 -dihydroxy-4,4 -diamino-biphenyI with 2,3,5,6-tetramethyI-l,4-phenyIenediamine or 9,9 -bis(4-aminophenyl)fluorene, thermally rearranged into poly(benzoxazole-co-imide), were tested [107]. 

Pareek K, Ghosh A, Sen SK, Banerjee S. Synthesis, characterization and properties of new fluorinated poly(imide siloxane) copolymers from 4,4 -(hexafluoro-isopropylid-ene)diphthalic anhydride. Des Monomers Polym 2010 13(3) 221-36. 

Brunelle DJ, Ye Q. Method for preparing oxy-diphthalic anhydrides using guanidinium salt as catalyst. US patent 6706897, assigned to General Electric Company, Niskayuna, NY 2004. 

Figure 7.9 Interfacial polymerization reaction taking place between a Cd-based metal organic framework and a 6FDA-based polyimide. 6FDA, 4,4 -(Hexafluoroisopropylidene)diphthalic anhydride ODA, oxydianiline...

A fluorinated aromatic dianhydride, 4,4 -(2,2,2-tri-fluoro-l-[3,5-ditrifluoromethylphenyl]ethylidene) diphthalic anhydride (9FDA) (3-55 in Scheme 3.8) was synthesized by Li et al. [107] and the solubility, thermal, and mechanical properties as well as electrical and optical properties were systematically investigated. Transmittance of the polyimide films at450nm... 

In a different smdy, they synthesized another five series of poly(ether imide)s based on five different cardo moiety containing diamines, designated as BPI, BAPA, FBP, BIDA, and SBPDA, as presented in Scheme 3.21. Five different aromatic dianhydride, 4,4 -(4,4 -isopropylidenediphenoxy) w(phthalic anhydride) (BPADA), 4,4 -(hexafluoro-isopropyli-dene) diphthalic anhydride (6-FDA), 3,3 4,4"-benzo-phenone tetracarboxylic acid dianhydride (BTDA), 4,4 -oxydiphthalic anhydride (ODPA), and benzene-1,2,4,5-tetracarboxylic dianhydride (PMDA), were used to prepare each series of poly(ether imide)s. The O2-N2 and CO2-CH4 separation properties for... 

H. Li, J. Liu, K. Wang, L. Fan, S. Yang, Synthesis and characterization of novel fluorinated polyimides derived from 4,4 -[2,2,2-tri-fluoro-l-(3,5-ditrifluoromethylphenyl) ethyhdene]diphthalic anhydride and aromatic diamines. Polymer 47 (4) (2006) 1443-1450. 

PBO membranes prepared by the thermal rearrangement of the hydroxyl-containing polyimides or polyamides at elevated temperature were used for membrane-based gas separation. Lee s group has done considerable work on the thermally rearranged (TR) PBO membrane (TR-PBO) (Figure 5.38) for gas separation [67,80]. They had studied the effect of imidization methods on the properties of TR-PBO membranes. The final properties of the TR-PBO membranes depended on the synthetic methods to prepare polyimide precursors. There are three different routes for the synthesis of the polyimides (1) thermal, (2) chemical, and (3) solution thermal imidization using an azeotrope. They demonstrated the effect of these routes on the final properties of the PBOs. The precursor ort/jo-functional polyimides were synthesized from 4,4 -hexafiuoroisopropyli-dene diphthalic anhydrides and 2,2 -bis(3-amino-4-hydroxyphenyl)hexafiuoropropane. 

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