M. Castillo-ortega - Academia.edu (original) (raw)

Papers by M. Castillo-ortega

Research paper thumbnail of Antimicrobial activity of chitosan nanofibers obtained by electrospinning

Polymer International, 2011

Electrospinning technology is useful for making ultrafine drug-eluting fibers for the clinical tr... more Electrospinning technology is useful for making ultrafine drug-eluting fibers for the clinical treatment of wounds. We show the incorporation of an antimicrobial LfcinB-derived peptide into Pullulan nanofibers. The palindromic peptide LfcinB (21-25) Pal : RWQWRWQWR was synthesized, purified, and characterized by means of the RP-HPLC and MALDI-TOF MS methods. The peptide's antibacterial activity against the E. coli ATCC 25922 strain was evaluated, and the peptide LfcinB (20-25) Pal exhibited significant antibacterial activity. Nanofibers were obtained by electrospinning a Pullulan or Pullulan-LfcinB (21-25) Pal solution. The obtained nanofibers were characterized via microscopy (AFM and SEM) and RP-HPLC chromatography. The peptide incorporation efficiency was 31%. The Pullulan-LfcinB (21-25) Pal nanofibers were soluble in water, and the peptide was liberated immediately. The Pullulan-LfcinB (21-25) Pal nanofibers exhibited the same antibacterial activity against E. coli strain as the free peptide LfcinB (21-25) Pal. The results suggest that Pullulan-LfcinB (21-25) Pal nanofibers could be considered for designing and developing antibacterial wound dressings.

Research paper thumbnail of Conductometric uric acid and urea biosensor prepared from electroconductive polyaniline–poly( n-butyl methacrylate) composites

Sensors and Actuators B-chemical, 2002

Polyaniline–poly(n-butyl methacrylate) (PAn–PBMA) composite films were obtained by casting. The h... more Polyaniline–poly(n-butyl methacrylate) (PAn–PBMA) composite films were obtained by casting. The homogeneous films were prepared with poly(vinyl methyl ether) (PVME) and poly(vinyl ethyl ether) (PVEE) as dispersants, and the electric conductivity, mechanical properties and morphology were studied. The PAn integration to the composite is better when PVEE is used as dispersant, but the conductivity is higher when PVME is used. The

Research paper thumbnail of Effect of chitosan and temperature on spore germination of Aspergillus niger

Research paper thumbnail of Preparation by coaxial electrospinning and characterization of membranes releasing (−) epicatechin as scaffold for tissue engineering

Materials Science and Engineering: C, 2015

Preparation by coaxial electrospinning and characterization of membranes releasing (-) epicatechi... more Preparation by coaxial electrospinning and characterization of membranes releasing (-) epicatechin as scaffold for tissue engineering,

Research paper thumbnail of Urea sensing film prepared by extrusion from DBSA-doped polyaniline-poly(styrene-co-potassium acrylate) in a poly(n-butyl methacrylate) matrix

Sensors and Actuators B: Chemical, 2007

Films of n-dodecylbenzene sulfonic acid-doped polyaniline (PANIDBSA), poly(styrene-co-potassium a... more Films of n-dodecylbenzene sulfonic acid-doped polyaniline (PANIDBSA), poly(styrene-co-potassium acrylate) (PSAK) and poly(n-butyl methacrylate) (PBMA) were prepared by extrusion at different weight ratios. The electrical, mechanical and morphological properties of the films were studied and compared with those of films of PANIDBSA-PBMA in which the ionomer (PSAK) was not included. The PSAK incorporation improves the electrical properties, the tensile strength and

Research paper thumbnail of Amoxicillin embedded in cellulose acetate-poly (vinyl pyrrolidone) fibers prepared by coaxial electrospinning: Preparation and characterization

Materials Letters, 2012

ABSTRACT The optimal conditions for the preparation of a composite material of fibers of cellulos... more ABSTRACT The optimal conditions for the preparation of a composite material of fibers of cellulose acetate (CA), poly (vinyl pyrrolidone) (PVP), containing amoxicillin (Amoxi) within the fiber, CA/PVP-Amoxi/CA, were found. The geometrical, physical–chemical and thermal properties of the fibrous membranes containing CA, PVP and amoxicillin were characterized using FTIR spectroscopy, thermal analysis, SEM and TEM. Also, mechanical characterization of the fibers showed that the tensile strength of the membrane is not affected by the presence of amoxicillin within the fiber as compared with fibers without amoxicillin; however, the rigidity of the membrane decreases by approximately 45%. The effect of the pH on the release rate of amoxicillin was also studied. The amount of amoxicillin release and the k value increased with an increasing pH, from 61% for a pH 3.0 to 79% at pH 7.2, with k values of 0.2120 and 0.2609 respectively. An empirical model for the amoxicillin release was studied; the release of amoxicillin is assumed to obey a diffusion mechanism. These composite materials are recommended for solving the problem of possible loss of drug during the process of entrapment in the matrix with potential local application in biological media to treat dental or skin infections.

Research paper thumbnail of pH- and temperature-sensitive semi-interpenetrating network hydrogels composed of poly(acrylamide) and poly(γ-glutamic acid) as amoxicillin controlled-release system

Polymer Bulletin, 2012

Hydrogels of semi-interpenetrating networks composed of poly(acrylamide) (PAAm) and poly(γ-glutam... more Hydrogels of semi-interpenetrating networks composed of poly(acrylamide) (PAAm) and poly(γ-glutamic acid) (γ-PGA) with different proportions were studied as potential amoxicillin controlled-release devices. The effects of the hydrogels composition, pH, and temperature on the kinetics and final release of amoxicillin were determined in batch experiments. The release kinetic tests were conducted using a buffer solution as the release medium under pH

Research paper thumbnail of Ordered Polymer Fibers

Wiley Encyclopedia of Composites, 2011

ABSTRACT

Research paper thumbnail of Compatibilization of polyethylene/polyaniline blends with polyethylene-graft-maleic anhydride

Journal of Applied Polymer Science, 2011

Research paper thumbnail of Synthesis and swelling properties of pH- and temperature-sensitive interpenetrating polymer networks composed of polyacrylamide and poly(γ-glutamic acid)

Journal of Applied Polymer Science, 2011

ABSTRACT Novel hydrogels of interpenetrating polymer networks (IPNs) composed of polyacrylamide a... more ABSTRACT Novel hydrogels of interpenetrating polymer networks (IPNs) composed of polyacrylamide and poly(γ-glutamic acid) were synthesized. In these systems, both polymers were crosslinked independently; this reduced the potential loss of a polymer during the washing process, as often occurs in semi-IPN systems. Interpolymer interactions were investigated with Fourier transform infrared spectroscopy and differential scanning calorimetry. These studies suggested possible interactions between both polymers by the formation of hydrogen bonds. The swelling behavior of these hydrogels was analyzed by immersion of the hydrogel samples in deionized water at 25 and 37°C and in buffer solutions with pHs of 3, 7, and 10. The kinetics of swelling showed increases in the values of the swelling ratio with increasing immersion time in the swelling medium, molar proportion of the biopolymer in the hydrogel, temperature, and pH of the swelling medium. All of the hydrogels swelled rapidly and reached equilibrium in an average time of 40 min. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Research paper thumbnail of Piezo-resistance effect in composite based on cross-linked polydimethylsiloxane and polyaniline: potential pressure sensor application

Journal of Materials Science, 2012

Research paper thumbnail of Preparation of polyaniline submicro/nanostructures using l-glutamic acid: Loading and releasing studies of amoxicillin

Synthetic Metals, 2013

ABSTRACT Hybrid submicro/nanostructures of polyaniline (PANI) and l-glutamic acid (GA) were chemi... more ABSTRACT Hybrid submicro/nanostructures of polyaniline (PANI) and l-glutamic acid (GA) were chemically prepared with the addition of ammonium persulfate (APS) as the oxidant. Different GA and APS concentrations were investigated in order to obtain the optimal conditions for the formation of high aspect ratio structures. TEM, electrical and XPS characterizations revealed that at monomer:amino acid:oxidant molar ratio of 1:0.25:1, the PANI presented a fibrillar morphology with diameters in submicro and nanometric scale, the structures were coating with the GA and the GA doped the PANI backbone. The fibrillar structures of GA coated-PANI efficiently adsorbed therapeutic doses of amoxicillin and controlled release of the drug can be achieved in function of pH environment, with a maximum cumulative release of 98% at pH 9 within 48 h.

Research paper thumbnail of Adsorption and desorption of a gold–iodide complex onto cellulose acetate membrane coated with polyaniline or polypyrrole: a comparative study

Journal of Materials …, 2011

Cellulose acetate membranes (M1) with controlled thickness were coated with an electroconductive ... more Cellulose acetate membranes (M1) with controlled thickness were coated with an electroconductive polymer, and the resulting composites were characterized by SEM, XPS, electrical conductivity, and mechanical measurements. A comparative study of M1 coated with polyaniline (PANI) or with polypyrrole (PPy) for adsorption and subsequent desorption of a gold-iodide complex was performed. The PANI-coated M1 (M2) and that coated with PPy (M3) are effective adsorbents for recovery of the AuI 2 complex. The adsorption of gold on the membranes was attributed to the exchange between the dopant ions and the AuI 2 complex ions. The adsorption equilibrium data fitted the Langmuir isotherm model for both membranes M2 and M3. The desorption of the AuI 2 complex with a NH 4 OH solution 3 M reached 97% for M3 membrane. This study shows a convenient method for the recovery of gold through the use of a complex with iodine without cyanide solutions.

Research paper thumbnail of Preparation, characterization and release of amoxicillin from cellulose acetate and poly(vinyl pyrrolidone) coaxial electrospun fibrous membranes

Electrospinning is a method that has been used to prepare polymeric fibers, with diameters rangin... more Electrospinning is a method that has been used to prepare polymeric fibers, with diameters ranging from nanometers to a micrometer of polymers such as cellulose acetate (CA) and poly(vinyl pyrrolidone) (PVP), and to develop membranes with applications in microencapsulation, for controlled release of drugs and for chemical and biological sensors. This work shows the feasibility and optimal conditions for the preparation of fibrous composite membranes of cellulose acetate and poly(vinyl pyrrolidone), via electrospinning, and their morphology; FTIR, and mechanical characterization and the effect of pH on the release of amoxicillin were analyzed. Tubes of CA with diameters around 500 nm were obtained. It was found that the release behavior of the drug from these fibrous membranes was dependent on the pH of the medium. It was observed that the amount of amoxicillin released as a function of time for a pH equal to 7.2 was approximately three times higher than that observed for a pH equal to 3.0. This suggests a greater interaction of amoxicillin with components of the membrane at a pH equal to 3.0, most likely due to the formation of hydrogen bonds. These materials have potential application in gastrointestinal administration and for transdermal patches.

Research paper thumbnail of Fibrous membranes of cellulose acetate and poly(vinyl pyrrolidone) by electrospinning method: Preparation and characterization

Journal of Applied Polymer Science, 2010

Fibrous membranes of cellulose acetate (CA), poly(vinyl pyrrolidone) (PVP) and composite membrane... more Fibrous membranes of cellulose acetate (CA), poly(vinyl pyrrolidone) (PVP) and composite membranes of these polymers, were obtained by the electrospinning method. Using systematic method, the optimal conditions for preparation of fibrous membranes were found. Both CA and PVP a concentration of 8% weight was found. The CA was dissolved in a acetone:water solution, volume ratio 80 : 20 and the PVP is dissolved in ethanol:water solution, ratio volume 85 : 15. The flow rate for both polymers was 1.5 mL h À1 . The same applied voltage value and the distance between the needle and collection plate were for polymer both, 15 kV and 15 cm respectively. The morphology of fibrous membranes and composite membranes were eval-uated by scanning electron microscopy (SEM). The CA fibers showed ribon morphology, while the PVP fibers were cilindric, in both cases with diameters in the micrometer range. Thermogravimetric analysis showed that CA had a complete degradation to 445 C, while the fibrous membranes PVP required a value of temperature for degradation of up to 571 C. Fibrous composite membrane PVP/CA/PVP shows a higher value of strain at break (%), and a lower value of tensile strength (MPa) compared to CA/PVP/CA.

Research paper thumbnail of Fibrous membranes of cellulose acetate and poly(vinyl pyrrolidone) by electrospinning method: Preparation and characterization

Journal of Applied Polymer Science, 2010

Fibrous membranes of cellulose acetate (CA), poly(vinyl pyrrolidone) (PVP) and composite membrane... more Fibrous membranes of cellulose acetate (CA), poly(vinyl pyrrolidone) (PVP) and composite membranes of these polymers, were obtained by the electrospinning method. Using systematic method, the optimal conditions for preparation of fibrous membranes were found. Both CA and PVP a concentration of 8% weight was found. The CA was dissolved in a acetone:water solution, volume ratio 80 : 20 and the PVP is dissolved in ethanol:water solution, ratio volume 85 : 15. The flow rate for both polymers was 1.5 mL h À1 . The same applied voltage value and the distance between the needle and collection plate were for polymer both, 15 kV and 15 cm respectively. The morphology of fibrous membranes and composite membranes were eval-uated by scanning electron microscopy (SEM). The CA fibers showed ribon morphology, while the PVP fibers were cilindric, in both cases with diameters in the micrometer range. Thermogravimetric analysis showed that CA had a complete degradation to 445 C, while the fibrous membranes PVP required a value of temperature for degradation of up to 571 C. Fibrous composite membrane PVP/CA/PVP shows a higher value of strain at break (%), and a lower value of tensile strength (MPa) compared to CA/PVP/CA.

Research paper thumbnail of Antimicrobial activity of chitosan nanofibers obtained by electrospinning

Polymer International, 2011

Electrospinning technology is useful for making ultrafine drug-eluting fibers for the clinical tr... more Electrospinning technology is useful for making ultrafine drug-eluting fibers for the clinical treatment of wounds. We show the incorporation of an antimicrobial LfcinB-derived peptide into Pullulan nanofibers. The palindromic peptide LfcinB (21-25) Pal : RWQWRWQWR was synthesized, purified, and characterized by means of the RP-HPLC and MALDI-TOF MS methods. The peptide's antibacterial activity against the E. coli ATCC 25922 strain was evaluated, and the peptide LfcinB (20-25) Pal exhibited significant antibacterial activity. Nanofibers were obtained by electrospinning a Pullulan or Pullulan-LfcinB (21-25) Pal solution. The obtained nanofibers were characterized via microscopy (AFM and SEM) and RP-HPLC chromatography. The peptide incorporation efficiency was 31%. The Pullulan-LfcinB (21-25) Pal nanofibers were soluble in water, and the peptide was liberated immediately. The Pullulan-LfcinB (21-25) Pal nanofibers exhibited the same antibacterial activity against E. coli strain as the free peptide LfcinB (21-25) Pal. The results suggest that Pullulan-LfcinB (21-25) Pal nanofibers could be considered for designing and developing antibacterial wound dressings.

Research paper thumbnail of Conductometric uric acid and urea biosensor prepared from electroconductive polyaniline–poly( n-butyl methacrylate) composites

Sensors and Actuators B-chemical, 2002

Polyaniline–poly(n-butyl methacrylate) (PAn–PBMA) composite films were obtained by casting. The h... more Polyaniline–poly(n-butyl methacrylate) (PAn–PBMA) composite films were obtained by casting. The homogeneous films were prepared with poly(vinyl methyl ether) (PVME) and poly(vinyl ethyl ether) (PVEE) as dispersants, and the electric conductivity, mechanical properties and morphology were studied. The PAn integration to the composite is better when PVEE is used as dispersant, but the conductivity is higher when PVME is used. The

Research paper thumbnail of Effect of chitosan and temperature on spore germination of Aspergillus niger

Research paper thumbnail of Preparation by coaxial electrospinning and characterization of membranes releasing (−) epicatechin as scaffold for tissue engineering

Materials Science and Engineering: C, 2015

Preparation by coaxial electrospinning and characterization of membranes releasing (-) epicatechi... more Preparation by coaxial electrospinning and characterization of membranes releasing (-) epicatechin as scaffold for tissue engineering,

Research paper thumbnail of Urea sensing film prepared by extrusion from DBSA-doped polyaniline-poly(styrene-co-potassium acrylate) in a poly(n-butyl methacrylate) matrix

Sensors and Actuators B: Chemical, 2007

Films of n-dodecylbenzene sulfonic acid-doped polyaniline (PANIDBSA), poly(styrene-co-potassium a... more Films of n-dodecylbenzene sulfonic acid-doped polyaniline (PANIDBSA), poly(styrene-co-potassium acrylate) (PSAK) and poly(n-butyl methacrylate) (PBMA) were prepared by extrusion at different weight ratios. The electrical, mechanical and morphological properties of the films were studied and compared with those of films of PANIDBSA-PBMA in which the ionomer (PSAK) was not included. The PSAK incorporation improves the electrical properties, the tensile strength and

Research paper thumbnail of Amoxicillin embedded in cellulose acetate-poly (vinyl pyrrolidone) fibers prepared by coaxial electrospinning: Preparation and characterization

Materials Letters, 2012

ABSTRACT The optimal conditions for the preparation of a composite material of fibers of cellulos... more ABSTRACT The optimal conditions for the preparation of a composite material of fibers of cellulose acetate (CA), poly (vinyl pyrrolidone) (PVP), containing amoxicillin (Amoxi) within the fiber, CA/PVP-Amoxi/CA, were found. The geometrical, physical–chemical and thermal properties of the fibrous membranes containing CA, PVP and amoxicillin were characterized using FTIR spectroscopy, thermal analysis, SEM and TEM. Also, mechanical characterization of the fibers showed that the tensile strength of the membrane is not affected by the presence of amoxicillin within the fiber as compared with fibers without amoxicillin; however, the rigidity of the membrane decreases by approximately 45%. The effect of the pH on the release rate of amoxicillin was also studied. The amount of amoxicillin release and the k value increased with an increasing pH, from 61% for a pH 3.0 to 79% at pH 7.2, with k values of 0.2120 and 0.2609 respectively. An empirical model for the amoxicillin release was studied; the release of amoxicillin is assumed to obey a diffusion mechanism. These composite materials are recommended for solving the problem of possible loss of drug during the process of entrapment in the matrix with potential local application in biological media to treat dental or skin infections.

Research paper thumbnail of pH- and temperature-sensitive semi-interpenetrating network hydrogels composed of poly(acrylamide) and poly(γ-glutamic acid) as amoxicillin controlled-release system

Polymer Bulletin, 2012

Hydrogels of semi-interpenetrating networks composed of poly(acrylamide) (PAAm) and poly(γ-glutam... more Hydrogels of semi-interpenetrating networks composed of poly(acrylamide) (PAAm) and poly(γ-glutamic acid) (γ-PGA) with different proportions were studied as potential amoxicillin controlled-release devices. The effects of the hydrogels composition, pH, and temperature on the kinetics and final release of amoxicillin were determined in batch experiments. The release kinetic tests were conducted using a buffer solution as the release medium under pH

Research paper thumbnail of Ordered Polymer Fibers

Wiley Encyclopedia of Composites, 2011

ABSTRACT

Research paper thumbnail of Compatibilization of polyethylene/polyaniline blends with polyethylene-graft-maleic anhydride

Journal of Applied Polymer Science, 2011

Research paper thumbnail of Synthesis and swelling properties of pH- and temperature-sensitive interpenetrating polymer networks composed of polyacrylamide and poly(γ-glutamic acid)

Journal of Applied Polymer Science, 2011

ABSTRACT Novel hydrogels of interpenetrating polymer networks (IPNs) composed of polyacrylamide a... more ABSTRACT Novel hydrogels of interpenetrating polymer networks (IPNs) composed of polyacrylamide and poly(γ-glutamic acid) were synthesized. In these systems, both polymers were crosslinked independently; this reduced the potential loss of a polymer during the washing process, as often occurs in semi-IPN systems. Interpolymer interactions were investigated with Fourier transform infrared spectroscopy and differential scanning calorimetry. These studies suggested possible interactions between both polymers by the formation of hydrogen bonds. The swelling behavior of these hydrogels was analyzed by immersion of the hydrogel samples in deionized water at 25 and 37°C and in buffer solutions with pHs of 3, 7, and 10. The kinetics of swelling showed increases in the values of the swelling ratio with increasing immersion time in the swelling medium, molar proportion of the biopolymer in the hydrogel, temperature, and pH of the swelling medium. All of the hydrogels swelled rapidly and reached equilibrium in an average time of 40 min. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Research paper thumbnail of Piezo-resistance effect in composite based on cross-linked polydimethylsiloxane and polyaniline: potential pressure sensor application

Journal of Materials Science, 2012

Research paper thumbnail of Preparation of polyaniline submicro/nanostructures using l-glutamic acid: Loading and releasing studies of amoxicillin

Synthetic Metals, 2013

ABSTRACT Hybrid submicro/nanostructures of polyaniline (PANI) and l-glutamic acid (GA) were chemi... more ABSTRACT Hybrid submicro/nanostructures of polyaniline (PANI) and l-glutamic acid (GA) were chemically prepared with the addition of ammonium persulfate (APS) as the oxidant. Different GA and APS concentrations were investigated in order to obtain the optimal conditions for the formation of high aspect ratio structures. TEM, electrical and XPS characterizations revealed that at monomer:amino acid:oxidant molar ratio of 1:0.25:1, the PANI presented a fibrillar morphology with diameters in submicro and nanometric scale, the structures were coating with the GA and the GA doped the PANI backbone. The fibrillar structures of GA coated-PANI efficiently adsorbed therapeutic doses of amoxicillin and controlled release of the drug can be achieved in function of pH environment, with a maximum cumulative release of 98% at pH 9 within 48 h.

Research paper thumbnail of Adsorption and desorption of a gold–iodide complex onto cellulose acetate membrane coated with polyaniline or polypyrrole: a comparative study

Journal of Materials …, 2011

Cellulose acetate membranes (M1) with controlled thickness were coated with an electroconductive ... more Cellulose acetate membranes (M1) with controlled thickness were coated with an electroconductive polymer, and the resulting composites were characterized by SEM, XPS, electrical conductivity, and mechanical measurements. A comparative study of M1 coated with polyaniline (PANI) or with polypyrrole (PPy) for adsorption and subsequent desorption of a gold-iodide complex was performed. The PANI-coated M1 (M2) and that coated with PPy (M3) are effective adsorbents for recovery of the AuI 2 complex. The adsorption of gold on the membranes was attributed to the exchange between the dopant ions and the AuI 2 complex ions. The adsorption equilibrium data fitted the Langmuir isotherm model for both membranes M2 and M3. The desorption of the AuI 2 complex with a NH 4 OH solution 3 M reached 97% for M3 membrane. This study shows a convenient method for the recovery of gold through the use of a complex with iodine without cyanide solutions.

Research paper thumbnail of Preparation, characterization and release of amoxicillin from cellulose acetate and poly(vinyl pyrrolidone) coaxial electrospun fibrous membranes

Electrospinning is a method that has been used to prepare polymeric fibers, with diameters rangin... more Electrospinning is a method that has been used to prepare polymeric fibers, with diameters ranging from nanometers to a micrometer of polymers such as cellulose acetate (CA) and poly(vinyl pyrrolidone) (PVP), and to develop membranes with applications in microencapsulation, for controlled release of drugs and for chemical and biological sensors. This work shows the feasibility and optimal conditions for the preparation of fibrous composite membranes of cellulose acetate and poly(vinyl pyrrolidone), via electrospinning, and their morphology; FTIR, and mechanical characterization and the effect of pH on the release of amoxicillin were analyzed. Tubes of CA with diameters around 500 nm were obtained. It was found that the release behavior of the drug from these fibrous membranes was dependent on the pH of the medium. It was observed that the amount of amoxicillin released as a function of time for a pH equal to 7.2 was approximately three times higher than that observed for a pH equal to 3.0. This suggests a greater interaction of amoxicillin with components of the membrane at a pH equal to 3.0, most likely due to the formation of hydrogen bonds. These materials have potential application in gastrointestinal administration and for transdermal patches.

Research paper thumbnail of Fibrous membranes of cellulose acetate and poly(vinyl pyrrolidone) by electrospinning method: Preparation and characterization

Journal of Applied Polymer Science, 2010

Fibrous membranes of cellulose acetate (CA), poly(vinyl pyrrolidone) (PVP) and composite membrane... more Fibrous membranes of cellulose acetate (CA), poly(vinyl pyrrolidone) (PVP) and composite membranes of these polymers, were obtained by the electrospinning method. Using systematic method, the optimal conditions for preparation of fibrous membranes were found. Both CA and PVP a concentration of 8% weight was found. The CA was dissolved in a acetone:water solution, volume ratio 80 : 20 and the PVP is dissolved in ethanol:water solution, ratio volume 85 : 15. The flow rate for both polymers was 1.5 mL h À1 . The same applied voltage value and the distance between the needle and collection plate were for polymer both, 15 kV and 15 cm respectively. The morphology of fibrous membranes and composite membranes were eval-uated by scanning electron microscopy (SEM). The CA fibers showed ribon morphology, while the PVP fibers were cilindric, in both cases with diameters in the micrometer range. Thermogravimetric analysis showed that CA had a complete degradation to 445 C, while the fibrous membranes PVP required a value of temperature for degradation of up to 571 C. Fibrous composite membrane PVP/CA/PVP shows a higher value of strain at break (%), and a lower value of tensile strength (MPa) compared to CA/PVP/CA.

Research paper thumbnail of Fibrous membranes of cellulose acetate and poly(vinyl pyrrolidone) by electrospinning method: Preparation and characterization

Journal of Applied Polymer Science, 2010

Fibrous membranes of cellulose acetate (CA), poly(vinyl pyrrolidone) (PVP) and composite membrane... more Fibrous membranes of cellulose acetate (CA), poly(vinyl pyrrolidone) (PVP) and composite membranes of these polymers, were obtained by the electrospinning method. Using systematic method, the optimal conditions for preparation of fibrous membranes were found. Both CA and PVP a concentration of 8% weight was found. The CA was dissolved in a acetone:water solution, volume ratio 80 : 20 and the PVP is dissolved in ethanol:water solution, ratio volume 85 : 15. The flow rate for both polymers was 1.5 mL h À1 . The same applied voltage value and the distance between the needle and collection plate were for polymer both, 15 kV and 15 cm respectively. The morphology of fibrous membranes and composite membranes were eval-uated by scanning electron microscopy (SEM). The CA fibers showed ribon morphology, while the PVP fibers were cilindric, in both cases with diameters in the micrometer range. Thermogravimetric analysis showed that CA had a complete degradation to 445 C, while the fibrous membranes PVP required a value of temperature for degradation of up to 571 C. Fibrous composite membrane PVP/CA/PVP shows a higher value of strain at break (%), and a lower value of tensile strength (MPa) compared to CA/PVP/CA.