Formation and analysis of a polyimide layer in composite membranes

Polotskaya, G. A.; Sklizkova, V. P.; Kozhurnikova, N. D.; Elyashevich, G. K.; Kudryavtsev, V. V.

doi:10.1002/(sici)1097-4628(20000222)75:8<1026::aid-app7>3.0.co;2-l

Cited by 12 publications

(4 citation statements)

References 6 publications

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“…Several polymer-C 60 composites, namely C 60 plus polyethylene [12], polystyrene [13], acrylic [14][15][16][17] or vinyl polymers [18], etc., have been studied. Polyimides (PIs) are high-temperature polymers, exhibiting a wide range of applications, as for example, in the preparation of films [19], fibers [20], foams [21] and membranes [22]. Recently, combinations of polyimides (PIs) with fullerene C 60 have received some attention [23,24] due to their interesting properties.…”

Section: Introductionmentioning

confidence: 99%

Nanostructure evolution during thermal treatment of polyimide–fullerene composites as revealed by WAXS and SAXS

Cagiao

Pozdnyakov

Krumova

et al. 2007

Composites Science and Technology

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The nanostructure formation in polyimide-fullerene composites during thermal treatment was investigated ''in situ'', by means of wide-angle (WAXS) and small-angle X-ray scattering techniques. The WAXS patterns of the PI composites do not reveal the presence of C 60 reflections. However, the PI/C 60 composite, obtained by adding the C 60 solution to the diamines-solution during the first step of the reaction (preparation of the polyamic acid, PAA), shows a maximum at small X-ray scattering angles. Results show that this intensity maximum is markedly affected by thermal treatment of the PI/C 60 composite, disappearing at high temperature. From ''in situ'' X-ray scattering experiments, the ''manner'' in which the C 60 nanoparticles are added to the other reactants and influences the properties of the final polymer is discussed.

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Section: Introductionmentioning

confidence: 99%

Nanostructure evolution during thermal treatment of polyimide–fullerene composites as revealed by WAXS and SAXS

Cagiao

Pozdnyakov

Krumova

et al. 2007

Composites Science and Technology

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“…Therefore, the development of new polymers for membranes with high performance and selectivity is of scientific and practical significance. Aromatic polyimides have many valuable physicomechanical properties and improved chemical and thermal stability, which are important for their use in gas separation and ultrafiltration and microfiltration 1–3. The specific chemical structure of polyimides profoundly affects liquid mixture separation by pervaporation (PV).…”

Section: Introductionmentioning

confidence: 99%

Pervaporation membranes based on imide‐containing poly(amic acid) and poly(phenylene oxide)

Polotskaya

Kuznetsov

Goĭkhman

et al. 2003

J of Applied Polymer Sci

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Three imide-containing poly(amic acids) were synthesized and used for homogeneous and composite membrane preparation. The transport properties of composite membranes consisting of an imide-containing poly(amic acid) top layer on an asymmetric porous poly(phenylene oxide) support were studied in the pervaporation of aqueous solutions of organic liquids (ethanol, isopropanol, acetone, and ethylacetate) and organic/organic mixtures (ethylacetate/ethanol, methanol/cyclohexane). For most of the aqueous/organic mixtures, the composite membranes exhibited dehydration properties. Dilute aqueous solutions of ethylacetate were an exception. In these solutions, the composite membranes exhibited organophilic properties, high permeability, and selectivity with respect to ethylacetate. In the pervaporation of methanol/cyclohexane mixtures, methanol was removed with very high selectivity. To account for specific features of pervaporation on the composite membranes, the sorption and transport properties of homogeneous membranes prepared from polymers comprising the composite membrane [imide-containing poly(amic acids) and poly(phenylene oxide)] were studied.

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“…A number of attempts have been made to fabricate composite polyimide membranes from poly(amic acid), PAA, precursors. − Poly(amic acid) polymers are frequently processed into the target article utilizing aggressive aprotic solvents, such as DMF. This makes it difficult to form composite membranes from PAA precursors.…”

Section: Introductionmentioning

confidence: 99%

“…For this and other reasons, fabrication of composite polyimide membranes from the poly(amic acid) precursors has achieved limited success. Most recently, Polotskaya et al reported fabrication of composite polyimide membranes from poly(amic acid) solutions containing large amounts of imidazole or benzimidazole. , They found that the use of these specific membrane casting compositions significantly lowered the imidization temperature. However, the authors used a high-temperature boiling solvent, DMF, and a nonvolatile catalyst in composite membrane preparation that presented severe drawbacks.…”

Section: Introductionmentioning

confidence: 99%

Polyimide Membranes Derived from Poly(amic acid) Salt Precursor Polymers. 2. Composite Membrane Preparation

2001

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A novel two-step process for fabrication of composite polyimide hollow fiber membranes using poly(amic acid) tertiary amine salts, PAAS, is described. In the first step, a precursor membrane is formed by depositing a thin PAAS polymer layer from an alcohol-based solution onto a porous hollow fiber substrate. In the second step, the final composite polyimide membrane is obtained upon thermal treatment of the precursor composite PAAS membrane at 150 °C. The novel process was demonstrated by preparing a composite polyimide membrane on a polysulfone hollow fiber substrate from the PAAS polymer (6FDA-ODA/Et 3N) derived from 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 4,4′-oxydianiline (ODA), and triethylamine. The surface layer and cross section of the precursor composite PAAS membrane and the final polyimide membrane were studied by SEM. The quantitative transformation of PAAS prepolymer into the respective polyimide by heat treatment at 150 °C was confirmed by ATR FT-IR analyses. Gas permeation characteristics of composite PAAS and polyimide membranes were measured and are reported.

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Formation and analysis of a polyimide layer in composite membranes

Cited by 12 publications

References 6 publications

Nanostructure evolution during thermal treatment of polyimide–fullerene composites as revealed by WAXS and SAXS

Nanostructure evolution during thermal treatment of polyimide–fullerene composites as revealed by WAXS and SAXS

Pervaporation membranes based on imide‐containing poly(amic acid) and poly(phenylene oxide)

Polyimide Membranes Derived from Poly(amic acid) Salt Precursor Polymers. 2. Composite Membrane Preparation

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