丝素/羧甲基壳聚糖共混膜的结构性能探讨

将含有甘油和戊二醛的丝素与羧甲基壳聚糖按一定比例混合,制得丝素/羧甲基壳聚糖共混膜,对共混膜的结构与性能进行了探讨。结果表明:随着羧甲基壳聚糖含量的增加,共混膜的透气率增大,加入交联剂戊二醛有效地改善了共混膜的力学性能,但其透气率有所降低;当丝素与羧甲基壳聚糖的质量比为4/1时,共混膜的断裂强度最大,力学性能较好,共混膜相容性较好,其断面光滑、致密。制备丝素/羧甲基壳聚糖共混膜的较佳条件为:丝素中的甘油质量分数为15%,戊二醛质量分数为0.075%,丝素与羧甲基壳聚糖质量比为4/1。     

Structural changes and their effect on mechanical properties of silk fibroin/chitosan blends

Silk fibroin/chitosan blend films were prepared by the solvent casting method. Miscibility between silk fibroin and chitosan was examined by dynamic mechanical thermal analysis. Structural changes of silk fibroin by the addition of chitosan were investigated by IR spectroscopy. The conformational transition of silk fibroin from random coil form to β‐sheet structure induced by blending with chitosan resulted in the increase of crystallinity and density of the blend films. The blend film containing 30 wt % chitosan exhibited a maximum increase in crystallinity and density. It was found that the tensile strength and initial tensile modulus of blend films were greatly enhanced with increasing the chitosan content and showed a maximum value at the composition of 30 wt % chitosan. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2571–2575, 1999     

Physical properties of silk fibroin/chitosan blend films

Silk fibroin/chitosan blend films were examined through IR spectroscopy to determine the conformational changes of silk fibroin. The effects of the fibroin/chitosan blend ratios (chitosan content) on the physical and mechanical properties were investigated to discover the feasibility of using these films as biomedical materials such as artificial skin and wound dressing. The mechanical properties of the blend films containing 10–40% chitosan were found to be excellent. The tensile strength, breaking elongation, and Young's modulus were affected by the chitosan contents of the blend films, which were also related to the density and degree of swelling. The coefficient of water vapor permeability of the blend films increased linearly with the chitosan content, and the values of 1000–2000 g m^?2 day^?1 were comparable to those of commercial wound dressings. Silk fibroin/chitosan blend films had good oxygen and water vapor permeabilities, making them useful as biomaterials. In particular, the blend film containing 40–50% chitosan showed very high oxygen permeability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 928–934, 2001     

Compatibilization of acrylic polymer–silk fibroin blend fibers: 2. Morphology and mechanical properties of the compatilized blend fibers

Three synthesized acrylonitrile-graft-silk fibroin copolymers (AN-g-SF), denoted as COP-65, COP-87, and COP-106, were used as potential compatilizers for acrylic polymer–silk fibroin blend fibers. Due to their different molecular weights and architecture, the compatibilizing efficiency is in the order of COP-106 > COP-65 > COP-87. To maintain the “sheath-core” structure of the blend fiber, COP-65 was chosen as the compatilizer. It was found that the addition of a small amount of COP-65 (up to 2 wt %) results in finer and more even distribution of the SF fibrils. On the contrary, excess COP-65 will cause flocculation and coalescence of the SF phase. Similarly, mechanical properties are enhanced with an optimum amount of the compatilizers. However, when excess COP-65 is added, the mechanical properties of the blend fibers are even worse than that of the uncompatilized samples. The mechanism of these findings is also discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2255–2264, 1999     

Characterization and performance evaluations of sodium zeolite‐Y filled chitosan polymeric membrane: Effect of sodium zeolite‐Y concentration

Sodium zeolite‐Y (NaY zeolite) filled chitosan polymeric membranes were developed and characterized. The impact of adding different concentrations of NaY zeolite into the homogeneous chitosan membrane was investigated. The surface morphology, mechanical–physical properties, sorption, and pervaporation performance for the dehydration of isopropanol–water mixture separation by the pervaporation process were studied and evaluated. A homogeneous chitosan membrane showed preferential water sorption and permeation compared to isopropanol. The optimum concentration of NaY zeolite added to the homogeneous chitosan membrane was 0.4 wt %, which showed that the dispersion of the NaY zeolite was the most homogeneous and finely covered by the chitosan polymer in the zeolite–chitosan polymer interface. The tensile strength and percent strain at maximum of this membrane were 59.347 MPa and 27.5%, respectively. The sorption experiments showed that the degree of swelling was 6.54% with 1.01 wt % isopropanol sorbed in these membranes. The pervaporation separation tests demonstrated that the NaY zeolite filled chitosan membrane was capable for isopropanol–water mixture separation and improved the pervaporation separation index from 272 (homogeneous chitosan membrane) to 2687. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1740–1751, 2006     

Acrylic polymer–silk fibroin blend fibers

Blends of acrylic polymer (containing acrylonitrile 91.7%, methyl acrylate 7%, and sodium methyl propenyl sulfonate 1.3% [wt %], denoted as PAC) with silk fibroin (SF) were studied in the form of drawn fibers with varied compositions. The strength, elongation, and specific work of rupture of the blend fibers decrease with increase of the SF content, whereas the modulus has a slight increase up to 20% (wt) SF and then decreases. With the addition of up to 30% (wt %) SF in the PAC matrix, the moisture absorption increases from 2.06 to 6.2% in comparison with the PAC. Scanning electron microscopy studies show that the blend fibers have a sheath–core structure, with SF mainly in the sheath and PAC in the core. FTIR, ATR, and X-ray diffraction results of the blend fibers are also presented. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:959–966, 1997     

Structure and physical properties of silk fibroin/polyacrylamide blend films

This article deals with the characterization of blend films obtained by mixing silk fibroin (SF) and polyacrylamide (PAAm). The DSC curves of SF/PAAm blend films showed overlapping of the main thermal transitions characteristic of the individual polymers. The exothermic peak at 218°C, assigned to the β‐sheet crystallization of silk fibroin, slightly shifted to a lower temperature by blending. The weight‐retention properties (TG) of the blend films were intermediate between those of the two constituents. The TMA response was indicative of a higher thermal stability of the blend films, even at low PAAm content (≤25%), the final breaking occurring at about 300°C (100°C higher than pure SF film). The peak of dynamic loss modulus of silk fibroin at 193°C gradually shifted to lower temperature in the blend films, suggesting an enhancement of the molecular motion of the fibroin chains induced by the presence of PAAm. Changes in the NH stretching region of silk fibroin were detected by FTIR analysis of blend films. These are attributable to disturbance of the hydrogen bond pattern of silk fibroin and formation of new hydrogen bonds with PAAm. The values of strength and elongation at break of blend films slightly improved at 20–25% PAAm content. A sea–island structure was observed by examining the air surface of the blend films by scanning electron microscopy. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1563–1571, 1999     

丝素/羧甲基壳聚糖共混膜的结构与性能

利用丝素(SF)与羧甲基壳聚糖(CMCS)共混制取不同比例的SF/CMCS共混膜。研究了CMCS诱导的丝素构象转变行为,测试了共混膜的吸湿性、透湿性和保水性。当CMCS的质量分数为5%时,共混膜中丝素的构象以β-折叠为主;当CMCS的质量分数为10%时,共混膜中丝素的构象由β-折叠向α-螺旋发生转变;当CMCS的质量分数达到15%时,共混膜中丝素的构象向无规卷曲发生转变。当CMCS质量分数小于15%时,共混膜中SF与CMCS具有良好的相容性,溶胀度较小,吸湿性随CMCS含量的增加而迅速降低。     

Separation of alkane–acetone mixtures using styrene–butadiene rubber/natural rubber blend membranes

Conventionally vulcanized styrene–butadiene rubber/natural rubber blend membranes were prepared for the pervaporation separation of alkane–acetone mixtures. Swelling measurements were carried out in both acetone and n‐alkanes to investigate the swelling behavior of the membranes. The swelling behavior was found to depend on the composition of the blend. The effects of blend ratio, feed composition, and penetrant size on the pervaporation process were analyzed. The permeation properties have been explained on the basis of interaction between the membrane and solvents and blend morphology. The SBR/NR 70/30 blend membrane showed higher selectivity among all the membranes used. Flux increases with increasing alkane content in the feed composition. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3059–3068, 1999     

Characterization of sodium alginate and poly(vinyl alcohol) blend membranes in pervaporation separation

By blending a rigid polymer, sodium alginate (SA), and a flexible polymer, poly(vinyl alcohol) (PVA), SA/PVA blend membranes were prepared for the pervaporation separation of ethanol–water mixtures. The rigid SA membrane showed a serious decline in flux and a increase in separation factor due to the relaxation of polymeric chains, whereas the flexible PVA membrane kept consistent membrane performance during pervaporation. Compared with the nascent SA membrane, all of the blend membranes prepared could have an enhanced membrane mobility by which the relaxation during pervaporation operation could be reduced. From the pervaporation separation of the ethanol–water mixtures along with the temperature range of 50–80°C, the effects of operating temperature and PVA content in membrane were investigated on membrane performance, as well as the extent of the relaxation. The morphology of the blend membrane was observed with PVA content by a scanning electron microscopy. The relaxational phenomena during pervaporation were also elucidated through an analysis on experimental data of membrane performance measured by repeating the operation in the given temperature range. SA/PVA blend membrane with 10 wt % of PVA content was crosslinked with glutaraldehyde to enhance membrane stability in water, and the result of pervaporation separation of an ethanol–water mixture through the membrane was discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:949–959, 1998     

聚乳酸/丝素共混膜的制备及其性能

用分子量为10万的聚乳酸（PLLA）对丝素膜进行改性,研究不同的聚乳酸加入量对丝素膜性能的影响,对聚乳酸/丝素共混膜进行了一系列表征。万能电子试验机的测试结果表明,经聚乳酸改性后,丝素膜的断裂强度,断裂伸长率有了较大的改善,当加入聚乳酸占丝素质量为5%时,丝素膜的强度可达到27.1 MPa,伸长率达4.4%; 改性后的丝素膜的亲水性有一定程度降低,溶失率则明显减小,透汽透湿性也有所提高;红外光谱测试表明,改性后的丝素膜含有较多的β构象成分。     

Separation properties of alcohol–water mixture through silicalite-I-filled silicone rubber membranes by pervaporation

The structure and the adsorption–desorption properties of zeolite silicalite-I by different treatments after synthesis were studied. The pervaporation properties of the alcohol–water mixture through silicone rubber filled with zeolite silicalite-I by different treatments were also investigated. Treating silicalite-I by acid or/and under steam was found to eliminate the metallic impurities in the zeolite and to perfect the crystalline structure of the zeolite. After treatment, silicalite-I is more selective to alcohol and the desorption of the alcohol from the zeolite is also easier. The silicone rubber membrane filled with treated silicalite-I shows a high performance for alcohol extraction from the dilute aqueous solution by pervaporation. The separation factor of the poly(dimethyl siloxane) (PDMS) membrane filled with silicalite-I treated successively by acid and steam is about 30 when the ethanol content in the feed is 5 wt % at 50°C. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 629–636, 1998     

Preparation and characterization of soy protein isolate–carboxymethylated konjac glucomannan blend films

To improve the mechanical and water vapor barrier properties of soy protein films, the transparent films were prepared by blending 5 wt % soy protein isolate (SPI) alkaline water solution with 2 wt % carboxymethylated konjac glucomannan (CMKGM) aqueous solution and drying at 30 °C. The structure and properties of the blend films were studied by infrared spectroscopy, wide‐angle X‐ray diffraction spectroscopy, scanning electron microscopy, thermogravimetric analysis, differential thermal analysis, and measurements of mechanical properties and water vapor transmission. The results demonstrated a strong interaction and good miscibility between SPI and CMKGM due to intermolecular hydrogen bonding. The thermostability and mechanical and water vapor barrier properties of blend films were greatly enhanced due to the strong intermolecular hydrogen bonding between SPI and CMKGM. The tensile strength and breaking elongation of blend films increased with the increase of CMKGM content: the maximum values achieved were 54.6 MPa and 37%, respectively, when the CMKGM content was 70 wt %. The water vapor transmission of blend films decreased with the increase of CMKGM content: the lowest value achieved was 74.8 mg · cm^?2 · d^?1 when the CMKGM content was 70 wt %. The SPI–CMKGM blend films provide promising applications to fresh food packaging. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1095–1099, 2003     

Properties and pervaporation characteristics of chitosan–poly(N‐vinyl‐2‐pyrrolidone) blend membranes for MeOH–MTBE

Clear blends of chitosan with poly(N‐vinyl‐2‐pyrrolidone) (PVP) made from aqueous solutions appear to be miscible from visual appearance. Infrared (IR) spectra used to investigate the carbonyl—hydroxyl hydrogen bonding in the blends indicated compatibility of two polymers on a molecular level. The IR spectra were also used to determine the interaction change accessing with increasing temperature and indicated that a significant conformational change occurred. On the other hand, the blend membranes were evaluated for separation of methanol from methyl tert‐butyl ether. The influences of the membrane and the feed compositions were investigated. Methanol preferentially permeates through all the tested membranes, and the partial flux of methanol significantly increase with the poly(N‐vinyl‐2‐pyrrolidone) content increasing. The temperature dependence of pervaporation performance indicated that a significant conformational change occurred with increasing temperature. Combined with the IR results, the pervaporation properties are in agreement with characteristics of interaction between chain–chain within the blend membranes. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1452–1458, 1999     

Blend membranes of chitosan and poly(vinyl alcohol) in pervaporation dehydration of isopropanol and tetrahydrofuran

Blend membranes of a natural polymer, chitosan, with a synthetic polymer, poly(vinyl alcohol) (PVA), were prepared by solution casting and crosslinked with a urea formaldehyde/sulfuric acid (UFS) mixture. Chitosan was used as the base component in the blend system, whereas PVA concentration was varied from 20 to 60 wt %. Blend compatibility was studied by differential scanning calorimetry, and Fourier transform infrared spectroscopy was used to study membrane crosslinking. Membranes were tested for pervaporation dehydration of isopropanol and tetrahydrofuran (THF) at 30°C in close proximity to their azeotropic compositions. Membrane performance was assessed by calculating flux and selectivity. Swelling experiments performed in water + organic mixtures at 30°C were used to explain the pervaporation results. The blend membrane containing 20 wt % PVA when tested for 5 and 10 wt % water–containing THF and isopropanol feeds exhibited selectivity of 4203 and 17,991, respectively. Flux increased with increasing concentration of water in the feed. Selectivity was highest for the 20 wt % PVA‐containing blend membrane. The results of this study are unique in the sense that the crosslinking agent used—the UFS mixture—was novel. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1918–1926, 2007     

The novel alginate/N‐succinyl‐chitosan antibacterial blend fibers

Alginate/ N‐Succinyl‐chitosan (SCS) blend fibers, prepared by spinning their mixture solution through a viscose‐type spinneret into a coagulating bath containing aqueous CaCl₂, were studied for structure and properties with the aid of infrared spectroscopy (IR) and X‐ray diffraction (XRD). The results indicated a good miscibility between alginate and SCS, because of the strong interaction from the intermolecular hydrogen bonds. The best values of the dry tensile strength and breaking elongation were obtained when SCS content was 30 wt %. The wet tensile strength decreased with the increase of SCS content, and the wet breaking elongation achieved maximum value when the SCS content was 30 wt %. Introduction of SCS in the blend fiber improved water‐retention properties of blend fiber compared to pure alginate fiber. Antibacterial fibers, obtained by treating the fibers with aqueous solution of silver nitrate, exhibited good antibacterial activity to Staphylococcus aureus. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Chitosan/Gelatin Blend Membranes for Pervaporation Dehydration of 1,4-Dioxane

Abstract

This paper deals with the development of compatible blend membranes of chitosan (CS) and gelatin (GL) by solution casting and crosslinking with glutaraldehyde. The membranes were tested in pervaporation (PV) dehydration of 1,4-dioxane. Membrane characterizations by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, and a universal testing machine were done to understand their physicochemical properties and for their suitability under PV conditions. The blend membranes were more water selective compared to pristine chitosan membrane at 30°C. Flux increased with increasing wt.% of water of the feed and also by increasing the gelatin content of the blend, but selectivity decreased. Sorption experiments gave information on the interaction between feed mixture and membrane polymers. Membranes of this study could extract nearly 97 wt.% of water from the feed mixture. Arrhenius activation parameters and diffusion coefficients estimated from a temperature dependence of PV results could explain the PV results satisfactorily.     

Structure and properties of silk fibroin/carboxymethyl chitosan blend films

The secondary structure of silk fibroin (SF) and the compatibility of the two components were associated with the carboxymethyl chitosan (CMCS) content in SF/CMCS blend films. A rather complete conformation transition of SF from random coil to β-sheet occurred after adding 5% CMCS into the SF film, and the blend film exhibited a high crystallinity and a good compatibility. The conformation of SF changed from β-sheet to α-helix when blending 10% CMCS. When the CMCS content was up to 15%, the conformation of SF in blend films showed a transformation from β-sheet to a random coil and their crystallinities decreased evidently; accordingly, there was a two-phase separation structure for the blend films containing 15% CMCS or more. However, the intermolecular interaction between the two polymers still existed in blend film with 15% CMCS or more. The blend films with 5–10% CMCS content showed the lower moisture absorption, swelling capacity, and solubility in water. These properties of blend films increased when adding CMCS more than 15%.     

Development of a novel glucosamine/silk fibroin–chitosan blend porous scaffold for cartilage tissue engineering applications

Silk fibroin–chitosan blend is reported to be an attractive scaffold material for tissue engineering applications. In our earlier study, we developed a scaffold having an optimal silk fibroin–chitosan blend ratio of 80:20 and proved its potentiality for cartilage tissue engineering applications. Glucosamine is one of the major structural components of cartilage tissue. The present work investigates the effect of glucosamine components on the physicochemical and biocompatibility properties of this scaffold. To this end, varied amounts of glucosamine were added to silk fibroin–chitosan blend with the aim of improving various scaffold properties. The addition of glucosamine components did not show any significant change in physicochemical properties of silk fibroin–chitosan blend scaffolds. The composite scaffold showed an open pore structure with desired pore size and porosity. However, cell culture study using human mesenchymal stem cells derived from umbilical cord blood revealed an overall increase in cell supportive properties of glucosamine-added scaffolds. Cell viability, cell proliferation and glycosaminoglycan assays confirmed enhanced cell viability and proliferation of mesenchymal stem cells. Thus, this study demonstrated the beneficial effect of glucosamine on improving the cell supportive property of silk fibroin–chitosan blend scaffolds making it more potential for cartilage tissue regeneration. To the best of our knowledge, this is the first report on the study of glucosamine-added silk fibroin–chitosan blend porous scaffolds seeded with mesenchymal stem cells derived from umbilical cord blood.     

Preparation and characterization of chitosan/poly(vinyl alcohol) blend fibers

Chitosan and poly(vinyl alcohol) blend fibers were prepared by spinning their solution through a viscose‐type spinneret at 25°C into a coagulating bath containing aqueous NaOH and ethanol. The influence of coagulation solution composition on the spinning performance was discussed, and the intermolecular interactions of blend fibers were studied by infrared analysis (IR), X‐ray diffraction (XRD), and scanning electron micrograph (SEM) and by measurements of mechanical properties and water‐retention properties. The results demonstrated that the water‐retention properties and mechanical properties of the blend fibers increase due to the presence of PVA in the chitosan substract, and the mechanical strength of the blends is also related to PVA content and the degree of deacetylation of chitosan. The best mechanical strength values of the blend fibers, 1.82 cN/d (dry state) and 0.81 cN/d (wet state), were obtained when PVA content was 20 wt % and the degree of deacetylation of chitosan was 90.2%. The strength of the blend fibers, especially wet tenacity could be improved further by crosslinking with glutaraldehyde. The water‐retention values (WRV) of the blend fibers were between 170 and 241%, obviously higher than pure chitosan fiber (120%). The structure analysis indicated that there are strong interaction and good miscibility between chitosan and poly(vinyl alcohol) molecular resulted from intermolecular hydrogen bonds. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2558–2565, 2001