Phosphatase Active Cross-Flow Microfiltration Poly(vinylidene Difluoride) Bioreactor

Roig, Manuel G.; Bello, J. F.; Rodrı́guez, Santiago; Kennedy, John F.; Taylor, David W.

doi:10.1002/(sici)1097-0126(199601)39:1<17::aid-pi441>3.0.co;2-b

Cited by 5 publications

(3 citation statements)

References 9 publications

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“…On the other hand, porous membranes with signal-responsive “polymer brushes” are advantageous over the hydrogel membrane in terms of mechanical strength and quick response to external stimuli. − Temperature-sensitive, pH-sensitive, or photosensitive polymeric membranes can be prepared by grafting the responsive polymers onto the existing porous membranes using various techniques. , These environmentally responsive membranes have been applied in controlled drug delivery , and chemical separation , and as bioreactors. , …”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Poly(N-isopropylacrylamide)-graft-Poly(vinylidene fluoride) Copolymers and Temperature-Sensitive Membranes

2002

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Molecular modification of ozone-pretreated poly(vinylidene fluoride) (PVDF) via thermally induced graft copolymerization with N-isopropylacrylamide (NIPAAM) in N-methyl-2-pyrrolidone solution was carried out (the NIPAAM-g-PVDF copolymer). The chemical structure and composition of the NIPAAM-g-PVDF copolymers were characterized by Fourier transform infrared spectroscopy, elemental analysis, and thermogravimetric analysis. In general, the graft concentration increased with the NIPAAM monomer concentration used for graft copolymerization. Microfiltration membranes were prepared from the NIPAAMg-PVDF copolymers by the phase inversion method. The bulk and surface graft concentrations of the membranes were obtained by elemental analysis and X-ray photoelectron spectroscopy (XPS), respectively. XPS analyses of the copolymer membranes revealed a substantial surface enrichment of the grafted NIPAAM polymer. The pore sizes of the pristine PVDF and the NIPAAM-g-PVDF membranes were measured using a Coulter Porometer. The morphology of the membranes was studied by scanning electron microscopy. The membrane surface composition, mean pore size, and morphology varied with the temperature of the casting bath. For the copolymer membrane cast below the lower critical solution temperature (LCST) of the NIPAAM polymer (∼32 °C), the rate of water permeation increased substantially at a permeate temperature above 32 °C. A reverse permeate temperature dependence was observed for the flux of 2-propanol through the membrane cast above the LCST of the NIPAAM polymer.

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“…On the other hand, porous membranes with signal-responsive “polymer brushes” are advantageous over the hydrogel membrane in terms of mechanical strength and quick response to external stimuli. − Temperature-sensitive, pH-sensitive, or photosensitive polymeric membranes can be prepared by grafting the responsive polymers onto the existing porous membranes using various techniques. , These environmentally responsive membranes have been applied in controlled drug delivery , and chemical separation , and as bioreactors. , …”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Poly(N-isopropylacrylamide)-graft-Poly(vinylidene fluoride) Copolymers and Temperature-Sensitive Membranes

2002

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“…On the other hand, porous membranes with signal-responsive “polymer brushes” are advantageous over the hydrogel membrane in terms of mechanical strength and quick response to external stimuli. − Certain polymeric materials are known to change reversibly their conformation and phase structures in response to the environmental stimuli, such as a change in temperature, pH, ionic strength, etc. − Membranes incorporating environmentally responsive polymers have been applied in controlled drug delivery, , chemical separation, , and bioreactors. , Environmental stimuli-sensitive membranes can be prepared by grafting of functional polymers or graft copolymerization of functional monomers directly onto the existing porous membranes. , These approaches, however, may be accompanied by changes in the membrane pore size and pore size distribution, leading to reduced permeability. − Furthermore, the extents of grafting on the membrane surface and the surfaces of the pores may differ substantially. Accordingly, the strategy of molecular or bulk graft copolymerization, followed by phase inversion, to membrane fabrication may prove to be particularly useful in certain cases.…”

Section: Introductionmentioning

confidence: 99%

pH-Sensitive Fluorinated Polyimides with Grafted Acid and Base Side Chains

Wang

Vora

Kang

et al. 2003

Ind. Eng. Chem. Res.

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Molecular modification of the ozone-pretreated fluorinated polyimide (FPI) via thermally induced graft copolymerization with either acrylic acid (AAc) or 4-vinylpyridine (4VP) in an N-methyl-2-pyrrolidone solution was carried out. The resulting FPI copolymers with grafted AAc and 4VP side chains (the PAAc-g-FPI and P4VP-g-FPI copolymers, respectively) were characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, and differential scanning calorimetry. In general, the graft concentration increased with the monomer concentration used for graft copolymerization. Microfiltration (MF) membranes were prepared from the PAAc-g-FPI or P4VP-g-FPI copolymers by phase inversion in aqueous media with pH values ranging from 1.0 to 6.4. The surface composition of the membranes was characterized by X-ray photoelectron spectroscopy. A substantial surface enrichment of the grafted AAc and 4VP polymer was observed for the copolymer membranes. The morphology of the MF membranes was studied by scanning electron microscopy. The pore sizes of the MF membranes were measured using a Coulter porometer. The flux of aqueous solutions through the PAAc-g-FPI and P4VP-g-FPI MF membranes exhibited a pH-dependent behavior but in an opposite manner, with the most drastic change in the permeation rate being observed at solution pH values between 1 and 4.

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“…Environmentally responsive polymer materials have been widely studied in recent years. Porous membranes with signal-responsive “polymer brushes” are advantageous over the hydrogel membrane in terms of mechanical strength and quick response to external stimuli, such as the change in temperature, pH, ionic strength, etc. − Membranes incorporating environmentally responsive polymers have been applied in controlled drug delivery, , in chemical separation, , and as bioreactors. , Temperature-sensitive N -isopropylacrylamide (NIPAAm) hydrogels can transform between the swollen and shrunken states reversibly in response to external temperature variations. − It exhibits a lower critical solution temperature (LCST) behavior at around 32 °C in an aqueous solution . The NIPAAm polymer chains hydrate to form an expanded structure in water when the solution temperature is below its LCST and dehydrate to form a compact structure when heated to above the LCST.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Fluorinated Polyimide with Grafted Poly(N-isopropylacrylamide) Side Chains and the Temperature-Sensitive Microfiltration Membranes

Wang

Ong

Lim

et al. 2003

Ind. Eng. Chem. Res.

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Molecular modification of a fluorinated polyimide (FPI), 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride + 4,4‘-bis(4-aminophenoxy)diphenyl sulfone, via ozone pretreatment and thermally induced graft copolymerization with N-isopropylacrylamide (NIPAAm) in a N-methyl-2-pyrrolidone solution, was carried out. The resulting FPIs with grafted NIPAAm polymer side chains [FPI-g-P(NIPAAm) copolymers] were cast into microfiltration membranes by phase inversion in water at temperatures ranging from 4 to 55 °C. The surface composition of the membranes was characterized by X-ray photoelectron spectroscopy. The surface composition, mean pore size, and morphology of the membrane varied with the temperature of the aqueous coagulation bath. For the copolymer membrane cast below the lower critical solution temperature of the NIPAAm polymer (∼32 °C), the rate of water permeation increased substantially at a permeate temperature above 32 °C. For the flux of 2-propanol through the membrane cast above 32 °C, a reversed permeate temperature dependence was observed.

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Phosphatase Active Cross-Flow Microfiltration Poly(vinylidene Difluoride) Bioreactor

Cited by 5 publications

References 9 publications

Synthesis and Characterization of Poly(N-isopropylacrylamide)-graft-Poly(vinylidene fluoride) Copolymers and Temperature-Sensitive Membranes

Synthesis and Characterization of Poly(N-isopropylacrylamide)-graft-Poly(vinylidene fluoride) Copolymers and Temperature-Sensitive Membranes

pH-Sensitive Fluorinated Polyimides with Grafted Acid and Base Side Chains

Synthesis and Characterization of Fluorinated Polyimide with Grafted Poly(N-isopropylacrylamide) Side Chains and the Temperature-Sensitive Microfiltration Membranes

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