Antimicrobial poly( vinyl alcohol)( PVA) nanofibrous composites were prepared by adding 3-( 2,3-dihydroxypropyl)-5,5-dimethylimidazolidine-2,4-dione( N-halamine diol) to the PVA solution using electro-spinning techniq...Antimicrobial poly( vinyl alcohol)( PVA) nanofibrous composites were prepared by adding 3-( 2,3-dihydroxypropyl)-5,5-dimethylimidazolidine-2,4-dione( N-halamine diol) to the PVA solution using electro-spinning technique upon curing and exposure to diluted sodium hypochlorite. Scanning electron microscopy( SEM) demonstrates that PVA nanofibers formed with diameters of( 255 ±94) nm. Cross-linked PVA nanofibers with N-halamine diol precursor and 1,2,3,4-butanetetracarboxylic( BTCA) showed good water resistance. The chlorinated PVA nanofibrous mats completely inactivated Staphylococcus aureus( Gram-positive) and Escherichia coli O157: H7( Gram-negative) with 7 log reductions( the reduction of the bacterial concentration in logarithm) within 5min and 1 min of contact time,respectively.展开更多
To investigate the influence of various processing parameters on the mechanical properties of fibers,lignin/graphene oxide(GO)/poly(vinyl alcohol)(PVA)fibers with different mass ratios of lignin and GO to PVA were pre...To investigate the influence of various processing parameters on the mechanical properties of fibers,lignin/graphene oxide(GO)/poly(vinyl alcohol)(PVA)fibers with different mass ratios of lignin and GO to PVA were prepared by gel spinning technique.Air drawing process and spinneret diameters were tuned as the main factors.The tensile strength increased up to 472 MPa with air drawing process applied in 30L0.05GO0.72D-A PVA fibers(air-drawn PVA fibers reinforced by 30%lignin and 0.05%GO spun with a spinneret diameter of 0.72 mm),indicating 17.4%higher than that of the fiber without air drawing process(402 MPa).Similarly,at least a 14.6%increase in Young's modulus has been achieved for 30L0.05GO0.72D-A fiber.In addition,a smaller spinneret diameter(0.72 mm)also led to a 24.9%increase in tensile strength and a 7.7%increase in Young's modulus in comparison with those of 5L0.05GO0.84D-A fibers.展开更多
Polymers and polymeric composites have steadily reflected their importance in our daily life. Blending poly(vinyl alcohol) (PVA) with a potentially useful natural biopolymers such as hydroxypropyl cellulose (HPC) seem...Polymers and polymeric composites have steadily reflected their importance in our daily life. Blending poly(vinyl alcohol) (PVA) with a potentially useful natural biopolymers such as hydroxypropyl cellulose (HPC) seems to be an interesting way of preparing a polymeric blends. In the present work, blends of PVA/HPC of compositions (100/0, 90/10, 75/25, 50/50, 25/75, and 0/100 wt/wt%) were prepared to be used as bioequivalent materials. Thermal analyses [differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)], and X-ray diffraction (XRD) were employed to characterize and reveal the miscibility map and the structural properties of such blend system. The obtained results of the thermal analyses showed variations in the glass transition temperature (Tg) indicating the miscibility of the blend systems. Moreover, the changes in the melting temperature (Tm), shape and area were attributed to the different degrees of crystallinity and the existence of polymer-polymer interactions between PVA and HPC molecules. The X-ray diffraction (XRD) analysis showed broadening and sharpening of peaks at different HPC concentrations with PVA. This indicated changes in the crystallinity/amorphosity ratio, and also suggested that the miscibility between the amorphous components of homo-polymers PVA and HPC is possible. The results showed that HPC doped in PVA film can improve the thermal stability of the film under investigation, leading to interesting technological applications.展开更多
This study investigates poly(vinyl alcohol) (PVA) membranes as controlled release micro-matrices, which can be useful in therapeutic applications for optimizing the administration of drugs. Currently, the use of hydro...This study investigates poly(vinyl alcohol) (PVA) membranes as controlled release micro-matrices, which can be useful in therapeutic applications for optimizing the administration of drugs. Currently, the use of hydrogels is limited by protein size. This study investigates the delivery of PspA, a large protein of approximately 38 kD. Pneumococcal surface protein A (PspA) has been shown to provide protective immunity against pneumococcal infection and is considered as a pneumococcal vaccine. The protein release experiments demonstrated that from an initial pH 7.4, approximately 60% of PspA diffuse into a neutral environment with an initial burst and a declining rate reaching equilibrium. The results indicate that the protein was successfully incorporated and released from the membrane over time. The hydrogel and protein interaction is temporary, and the membrane system is ideal for protein drug delivery. The data confirm that the protein did not aggregate and was active after release. The protein release is promising and a step forward to develop microneedles to facilitate high molecular weight protein delivery as well as vaccine delivery.展开更多
Fabricating of hydrogels based upon polymers and inorganic matter is an innovative replacement for the generation of adaptable matrices.In this study,the poly(vinyl alcohol)(PVA)/chitosan(CS)/soluble starch(SS)composi...Fabricating of hydrogels based upon polymers and inorganic matter is an innovative replacement for the generation of adaptable matrices.In this study,the poly(vinyl alcohol)(PVA)/chitosan(CS)/soluble starch(SS)composite hydrogel was prepared by the solution blending method,in which SS was used as a cross-linking agent to cross-link with PVA in order to improve the stability of PVA in the tissue fluid.The composition and the thermal stability of hydrogels were characterized by Fourier transform infrared(FTIR)spectroscopy and thermo gravimetric analysis(TGA).The result shows that the PVA/CS/SS composite hydrogel possesses potentially morphological and thermal stability and can be used for tissue engineering.展开更多
A porous,biocompatible,and modifiable chitosan (CS)/poly (vinyl alcohol) (PVA) hybrid membrane, which can be evaluated as wound dressing,has been prepared by lyophilization method and using the low toxicity solvents. ...A porous,biocompatible,and modifiable chitosan (CS)/poly (vinyl alcohol) (PVA) hybrid membrane, which can be evaluated as wound dressing,has been prepared by lyophilization method and using the low toxicity solvents. Experiments illustrated that the moisture regain and porosity rate of polymer blend membranes had the similar variation tendency and got the maximum value at the case of CS/PVA weight ratio of 6∶4. And the value of water vapor transmission rate( WVTR) is conductive to the healing of wound and desirable for the application as a wound dressing.Mechanical performance test of blend membrane showed that the presence of PVA could effectively improve the interaction between CS molecules. The scanning electron microscopy( SEM)photograph confirmed the porous surface on top-layer supported by a macroporous sponge-like sub-layer of this novel type of CS blend membrane. Besides, Fourier transform infrared spectroscopy( FTIR) revealed the facts that the two polymers were physically bended and certain chemical actions took place,which illustrated the good compatibility between them. Differential scanning calorimetry(DSC) results showed that decomposition reaction occurred in CS at about 210℃. Introducing of PVA to CS made the decomposition temperature of blend membrane decrease. The good properties,such as moisture regain,porosity rate,and WVTR,of this kind of CS/PVA blend membranes suggested a potential application as a wound dressing in the future.展开更多
Coaxial electrospinning process was used to produce biodegradable membranes made of coreshell fibers of a poly(lactic acid) (PLA) shell and a poly(vinyl alcohol) (PVA) core. Scanning electron microscopy analyses of th...Coaxial electrospinning process was used to produce biodegradable membranes made of coreshell fibers of a poly(lactic acid) (PLA) shell and a poly(vinyl alcohol) (PVA) core. Scanning electron microscopy analyses of these structures showed that the PLA shell can present certain porosity depending on the process condition. FTIR-ATR and contact angle measurements also suggested imprisonment of the PVA core within the PLA shell. This type of structure was also confirmed by means of transmissions electron microscopy. The morphology of these fibers was dependent on the flow rate of both core and shell solutions, and homogeneous and smooth surface was only attained when the flow rate of the external PLA solution was 4 times the flow rate of the internal PVA solution. The increase in the PLA solution flow rate increases the diameter of the core-shell fiber which reaches up to 1.7 μm. Nevertheless, fibers with smaller average diameter could also be produced (200 nm). These core-shell fibers presented improved hydrophilicity as compared with monolithic PLA fibers.展开更多
文摘Antimicrobial poly( vinyl alcohol)( PVA) nanofibrous composites were prepared by adding 3-( 2,3-dihydroxypropyl)-5,5-dimethylimidazolidine-2,4-dione( N-halamine diol) to the PVA solution using electro-spinning technique upon curing and exposure to diluted sodium hypochlorite. Scanning electron microscopy( SEM) demonstrates that PVA nanofibers formed with diameters of( 255 ±94) nm. Cross-linked PVA nanofibers with N-halamine diol precursor and 1,2,3,4-butanetetracarboxylic( BTCA) showed good water resistance. The chlorinated PVA nanofibrous mats completely inactivated Staphylococcus aureus( Gram-positive) and Escherichia coli O157: H7( Gram-negative) with 7 log reductions( the reduction of the bacterial concentration in logarithm) within 5min and 1 min of contact time,respectively.
基金Fundamental Research Funds for the Central Universities,China(Nos.20D110110 and 2232020G-01)National Natural Science Foundation of China(No.51903033)Shanghai Sailing Program,China(No.19YF1400800)。
文摘To investigate the influence of various processing parameters on the mechanical properties of fibers,lignin/graphene oxide(GO)/poly(vinyl alcohol)(PVA)fibers with different mass ratios of lignin and GO to PVA were prepared by gel spinning technique.Air drawing process and spinneret diameters were tuned as the main factors.The tensile strength increased up to 472 MPa with air drawing process applied in 30L0.05GO0.72D-A PVA fibers(air-drawn PVA fibers reinforced by 30%lignin and 0.05%GO spun with a spinneret diameter of 0.72 mm),indicating 17.4%higher than that of the fiber without air drawing process(402 MPa).Similarly,at least a 14.6%increase in Young's modulus has been achieved for 30L0.05GO0.72D-A fiber.In addition,a smaller spinneret diameter(0.72 mm)also led to a 24.9%increase in tensile strength and a 7.7%increase in Young's modulus in comparison with those of 5L0.05GO0.84D-A fibers.
文摘Polymers and polymeric composites have steadily reflected their importance in our daily life. Blending poly(vinyl alcohol) (PVA) with a potentially useful natural biopolymers such as hydroxypropyl cellulose (HPC) seems to be an interesting way of preparing a polymeric blends. In the present work, blends of PVA/HPC of compositions (100/0, 90/10, 75/25, 50/50, 25/75, and 0/100 wt/wt%) were prepared to be used as bioequivalent materials. Thermal analyses [differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)], and X-ray diffraction (XRD) were employed to characterize and reveal the miscibility map and the structural properties of such blend system. The obtained results of the thermal analyses showed variations in the glass transition temperature (Tg) indicating the miscibility of the blend systems. Moreover, the changes in the melting temperature (Tm), shape and area were attributed to the different degrees of crystallinity and the existence of polymer-polymer interactions between PVA and HPC molecules. The X-ray diffraction (XRD) analysis showed broadening and sharpening of peaks at different HPC concentrations with PVA. This indicated changes in the crystallinity/amorphosity ratio, and also suggested that the miscibility between the amorphous components of homo-polymers PVA and HPC is possible. The results showed that HPC doped in PVA film can improve the thermal stability of the film under investigation, leading to interesting technological applications.
文摘This study investigates poly(vinyl alcohol) (PVA) membranes as controlled release micro-matrices, which can be useful in therapeutic applications for optimizing the administration of drugs. Currently, the use of hydrogels is limited by protein size. This study investigates the delivery of PspA, a large protein of approximately 38 kD. Pneumococcal surface protein A (PspA) has been shown to provide protective immunity against pneumococcal infection and is considered as a pneumococcal vaccine. The protein release experiments demonstrated that from an initial pH 7.4, approximately 60% of PspA diffuse into a neutral environment with an initial burst and a declining rate reaching equilibrium. The results indicate that the protein was successfully incorporated and released from the membrane over time. The hydrogel and protein interaction is temporary, and the membrane system is ideal for protein drug delivery. The data confirm that the protein did not aggregate and was active after release. The protein release is promising and a step forward to develop microneedles to facilitate high molecular weight protein delivery as well as vaccine delivery.
基金National Nature Science Foundation of China(Nos.11702169 and 21808165)Shanghai University of Engineering Science,China(No.0239-e3-0507-19-05163)Scientific Research Staring Foundation of Shanghai University of Engineering Science,China(No.2017-19).
文摘Fabricating of hydrogels based upon polymers and inorganic matter is an innovative replacement for the generation of adaptable matrices.In this study,the poly(vinyl alcohol)(PVA)/chitosan(CS)/soluble starch(SS)composite hydrogel was prepared by the solution blending method,in which SS was used as a cross-linking agent to cross-link with PVA in order to improve the stability of PVA in the tissue fluid.The composition and the thermal stability of hydrogels were characterized by Fourier transform infrared(FTIR)spectroscopy and thermo gravimetric analysis(TGA).The result shows that the PVA/CS/SS composite hydrogel possesses potentially morphological and thermal stability and can be used for tissue engineering.
基金Natural Science Foundation of Shanghai,China(No.14ZR1401000)Shanghai University Students Innovation Project of China(No.sh201410255026)National Natural Science Foundation of China(No.51303021)
文摘A porous,biocompatible,and modifiable chitosan (CS)/poly (vinyl alcohol) (PVA) hybrid membrane, which can be evaluated as wound dressing,has been prepared by lyophilization method and using the low toxicity solvents. Experiments illustrated that the moisture regain and porosity rate of polymer blend membranes had the similar variation tendency and got the maximum value at the case of CS/PVA weight ratio of 6∶4. And the value of water vapor transmission rate( WVTR) is conductive to the healing of wound and desirable for the application as a wound dressing.Mechanical performance test of blend membrane showed that the presence of PVA could effectively improve the interaction between CS molecules. The scanning electron microscopy( SEM)photograph confirmed the porous surface on top-layer supported by a macroporous sponge-like sub-layer of this novel type of CS blend membrane. Besides, Fourier transform infrared spectroscopy( FTIR) revealed the facts that the two polymers were physically bended and certain chemical actions took place,which illustrated the good compatibility between them. Differential scanning calorimetry(DSC) results showed that decomposition reaction occurred in CS at about 210℃. Introducing of PVA to CS made the decomposition temperature of blend membrane decrease. The good properties,such as moisture regain,porosity rate,and WVTR,of this kind of CS/PVA blend membranes suggested a potential application as a wound dressing in the future.
基金the Brazilian Agencies CNPq,CAPES and FAPERJ for supporting this work
文摘Coaxial electrospinning process was used to produce biodegradable membranes made of coreshell fibers of a poly(lactic acid) (PLA) shell and a poly(vinyl alcohol) (PVA) core. Scanning electron microscopy analyses of these structures showed that the PLA shell can present certain porosity depending on the process condition. FTIR-ATR and contact angle measurements also suggested imprisonment of the PVA core within the PLA shell. This type of structure was also confirmed by means of transmissions electron microscopy. The morphology of these fibers was dependent on the flow rate of both core and shell solutions, and homogeneous and smooth surface was only attained when the flow rate of the external PLA solution was 4 times the flow rate of the internal PVA solution. The increase in the PLA solution flow rate increases the diameter of the core-shell fiber which reaches up to 1.7 μm. Nevertheless, fibers with smaller average diameter could also be produced (200 nm). These core-shell fibers presented improved hydrophilicity as compared with monolithic PLA fibers.
