4,4 -Hexafluoroisopropylidene diphthalic

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... 

By using hexafluoroisopropylidene diphthalic tetraacid dimethyl ester (HFDE) instead of BTDE and a mixture of meta- and para-phenylene (mPDA.pPDA) instead of MDA a new generation of more stable nadic resins has been developed (Fig. 34) [106]. Table 5 summarizes the Tgs and the thermo-oxidative properties of these materials as a function of their molecular weight. 

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. 

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. 

Cyclobutanetetracarboxylic dianhydride 4,4 -Hexafluoroisopropylidene diphthalic dianhydride 3,3, 4,4 -Biphenyl dianhydride... 

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]. 

Hexafluoroisopropylidene diphthalic dianhydride Figure 15.11 Dianhydrides for soluble Pis. 

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...

Synthesis of brominated polyimide 20. A 20 mL vial was charged with 4-bromo-4, 4"-diaminotriphenylamine (0.500 g, 1.412 mmol) and 2 g of dry NMP. The mixture was stirred until complete dissolution of the diamine was achieved, and then (hexafluoroisopropylidene)diphthalic anhydride (6-FDA) (0.627 g, 1.412 mmol) was added and washed in vntti another 2 g of NMP. The polymerization mixture turned dark red in color. It was stirred for a period of 48 h to yield a highly viscous polyamic acid solution PAA-1. 

PIE2 Polyimide synthesised from 4,4 -hexafluoroisopropylidene diphthalic dianhydride and 4,4 -diaminophenylmethane... 

Suda et al. [288] reported the synthesis and characterization of a series of sulfonated star-hb polyimides (S-hb-Pls) without any crosslinking for use as proton exchange membranes. Sulfonated anhydride-terminated polyimides with different molecular weights (M v = 59,000, 200,000 and 300,000 Da) based on monomer combination 1,4,5,8-naphthalene tetracarboxylic dianhydride/4,4 -diaminobiphenyl 2,2 -disulfonic acid (NTDA/BDSA) were synthesized using different molar ratios of BDSA NTDA. The amine-terminated hb-Pl based on monomer combination 4,4-(hexafluoroisopropylidene)diphthalic anhydride/tris(4-aminophenyl)amine (6EDA/TAPA) was also prepared. Scheme 33 shows the monomer combinations used for the preparation of (S-hb-Pl). 

Chen H, Yin J (2003) Preparatirai of auto-photosensitive hyperbranched co-polyimide by the condensation of 4,4 -(hexafluoroisopropylidene)diphthalic anhydride and 3,3, 4,4 -benzophenonetetracarboxylic dianhydride with l,3,5-tris(4-aminophenoxy)benzene through a stage addition reaction method. Polym Bull 50 303—310... 

Poly(hexafluoroisopropylidene diphthalic anhydride-ro-oxydianiline) Hexafluoroisopropylidenebis- 032240-73-6 (phthalie anhydride)-oxydianiline copolymer R (CisHsFsOft- CnHoNiO).,... 

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