Showing papers by "Lina Zhang published in 2005"
TL;DR: The results from DSC and (13)C NMR indicated that LiOH/urea and NaOH/UREa aqueous solutions as non-derivatizing solvents broke the intra- and inter-molecular hydrogen bonding of cellulose and prevented the approach toward each other of the cellulose molecules, leading to the good dispersion of cellulOSE to form an actual solution.
Abstract: Rapid dissolution of cellulose in LiOH/urea and NaOH/urea aqueous solutions was studied systematically. The dissolution behavior and solubility of cellulose were evaluated by using (13)C NMR, optical microscopy, wide-angle X-ray diffraction (WAXD), FT-IR spectroscopy, DSC, and viscometry. The experiment results revealed that cellulose having viscosity-average molecular weight ((overline) M eta) of 11.4 x 104 and 37.2 x 104 could be dissolved, respectively, in 7% NaOH/12% urea and 4.2% LiOH/12% urea aqueous solutions pre-cooled to -10 degrees C within 2 min, whereas all of them could not be dissolved in KOH/urea aqueous solution. The dissolution power of the solvent systems was in the order of LiOH/urea > NaOH/urea >> KOH/urea aqueous solution. The results from DSC and (13)C NMR indicated that LiOH/urea and NaOH/urea aqueous solutions as non-derivatizing solvents broke the intra- and inter-molecular hydrogen bonding of cellulose and prevented the approach toward each other of the cellulose molecules, leading to the good dispersion of cellulose to form an actual solution.
808 citations
TL;DR: Assays in vivo and in vitro against the growth of Sarcoma 180 solid tumor as well as the colorimetric 3-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method for lentinan showed that the triple-helix sample exhibited a relatively high inhibition ratio.
272 citations
TL;DR: Investigation at the molecular levels revealed that structural factors such as larger surface area of the beads resulted from microporous-network structure, low crystallinity of cellulose/chitin beads and high hydrophilicity induced by hydrophilic skeleton of cellulOSE played an important role in increasing adsorption ability.
259 citations
TL;DR: In this article, six water-soluble polysaccharides coded as GTM1 to GTM6 were extracted sequentially from the mycelium of Ganoderma tsugae.
118 citations
TL;DR: The results above suggest that protein-rich domains were composed of the compact chains of protein with relatively low compatibility to glycerol and glycerols consisted of relative loose chains that possessed good compatibility with Glycerol.
Abstract: Soy protein isolate (SPI) and glycerol were mixed under mild (L series) and severe (H series) mixing conditions, respectively, and then were compression-molded at 140 degrees C and 20 MPa to prepare the sheets (SL and SH series). The glass transition behaviors and microstructures of the soy protein plasticized with glycerol were investigated carefully by using differential scanning calorimetry and small-angle X-ray scattering. The results revealed that there were two glass transitions in the SPI/glycerol systems. When the glycerol contents ranged from 25 to 40 wt.-%, all of the SL- and SH-series sheets showed two glass transition temperatures (T(g1) and T(g2)) corresponding to glycerol-rich and protein-rich domains, respectively. The T(g1) values of the sheets decreased from -28.5 to -65.2 degrees C with an increase of glycerol content from 25 to 50 wt.-%, whereas the T(g2) values were almost invariable at about 44 degrees C. The results from wide-angle X-ray diffraction and small-angle X-ray scattering indicated that both protein-rich and glycerol-rich domains existed as amorphous morphologies, and the radii of gyration (R(g)) of the protein-rich domains were around 60 nm, a result suggesting the existence of stable protein domains. The results above suggest that protein-rich domains were composed of the compact chains of protein with relatively low compatibility to glycerol and glycerol-rich domains consisted of relative loose chains that possessed good compatibility with glycerol. The significant microphase separation occurred in the SPI sheets containing more than 25 wt.-% glycerol, with a rapid decrease of the tensile strength and Young's modulus. [illustration in text].
116 citations
TL;DR: In this article, the structure and properties of the blend fibers were studied with the aid of infrared spectra, scanning electron micrography, X-ray diffraction, and thermogravimetric analysis.
Abstract: Alginate and gelatin blend fibers were prepared by spinning their solution through a viscose-type spinneret into a coagulating bath containing aqueous CaCl2 and ethanol. The structure and properties of the blend fibers were studied with the aid of infrared spectra, scanning electron micrography, X-ray diffraction, and thermogravimetric analysis. Mechanical properties and water-retention properties were measured. The best values of the tensile strength and breaking elongation of blend fibers were obtained when gelatin content was 30 wt %. The water-retention values of blend fibers increase as the amount of gelatin is raised. The structural analysis indicated that there was strong interaction and good miscibility between alginate and gelatin molecules resulted from intermolecular hydrogen bonds. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1625–1629, 2005
106 citations
TL;DR: In this article, the uniform design method based on theoretical accomplishments in the number-theoretic method was used to optimize the coagulation conditions of H2SO4 aqueous solution with various concentrations (from 1 to 15 wt %), time, and temperature (from 25 to 55 °C).
Abstract: Effects of coagulant components and coagulation conditions on the structure and properties of regenerated cellulose (RC) films prepared from cellulose in 7.5 wt % NaOH/11 wt % urea aqueous solution were investigated by 13C NMR, X-ray diffraction, scanning electron micrograph, tensile testing, etc. The uniform design method based on theoretical accomplishments in the number-theoretic method was used to optimize the coagulation conditions of H2SO4 aqueous solution with various concentrations (from 1 to 15 wt %), time (from 1 to 15 min), and temperature (from 25 to 55 °C). Moreover, a series of RC films coagulated, with 5 wt % H2SO4/Na2SO4, Na2SO4, HOAc, and (NH4)2SO4, respectively; different concentrations (from 1 to 20 wt %) and times (from 1 to 20 min) at 25 °C were also investigated. The results indicated that the optimal coagulant concentrations and coagulation times of the RC films are 5 wt % H2SO4 for 5 min, 5 wt % H2SO4/5 wt % Na2SO4 for 5 min, 5 wt % Na2SO4 for 15 min, 3 wt % HOAc for 5 min, and 5 w...
103 citations
TL;DR: The result from small-angle X-ray scattering indicated that the radii of gyration of protein-rich domain were in the range of 60-63 nm; this suggested the existence of protein macromolecules as aggregates in the stable protein- rich and protein-water domains.
Abstract: The glass transition behavior of the glycerol-plasticized soy protein sheets (SL series) at various relative humidity (RH) was investigated by using differential scanning calorimetry with the aluminum pan and O-ring-sealed stainless steel capsule, and the microstructure of these sheets was detected on small-angle X-ray scattering. The results revealed that there were three glass transitions (Tg1, Tg2 and Tg3), corresponding to glycerol-rich, protein-rich and protein-water domains, in the protein-glycerol-water ternary system. The Tg1 values of the SL-series sheets at 75% RH decreased from -49.3 to -83.8 degrees C with an increase of glycerol content from 10 to 50 wt.-%, whereas Tg2 and Tg3 were almost invariable at about 60 degrees C and 3 degrees C, respectively. In addition, the Tg1, Tg2 and Tg3 values of the SL-25 containing 25 wt.-% glycerol at 0%, 35%, 58%, 75% and 98% RH were in the range of -12.7 - -83.2 degrees C, 65.8 - 53.1 degrees C and 3.5 - 1.9 degrees C, respectively. The result from small-angle X-ray scattering indicated that the radii of gyration (Rg) of protein-rich domain were in the range of 60-63 nm; this suggested the existence of protein macromolecules as aggregates in the stable protein-rich and protein-water domains. With an increase of RH, the tensile strength and Tg values of the SL-series sheets decreased, but the elongation at break increased. In view of the results above, the moisture in ambient environment significantly influenced the Tg values and microstructures of the glycerol-plasticized soy protein sheets, leading to the changes of the mechanical and thermal properties.
72 citations
TL;DR: In this paper, the authors synthesize styrene-butadiene rubber/montmorillonite (SBR/MMT) nanocomposites by in situ living anionic polymerization with n -BuLi as initiator.
66 citations
TL;DR: In this paper, the inorganic-organic hybrid materials composed of cadmium sulfide (CdS) semiconducting nanocrystals and regenerated cellulose (RC) were prepared by using in situ synthesizing method.
Abstract: Summary: Novel inorganic-organic hybrid materials composed of cadmium sulfide (CdS) semiconducting nanocrystals and regenerated cellulose (RC) were prepared by using in situ synthesizing method. Cellulose was dissolved in a 6 wt.-% NaOH/4 wt.-% urea/thiourea aqueous solution at low temperature followed by addition of cadmium chloride (CdCl2), resulting that the CdS nanocrystals were successfully grown in situ in the cellulose solution. Nanocomposite films containing homogeneous CdS nanoparticles were obtained by casting the resulting solution. Their structure and optical properties were characterized by X-ray photoelectron spectroscopy, wide-angle X-ray diffraction, thermogravimetry analysis, dynamic mechanical analysis, atomic force microscopy, transmittance electronic microscope, UV-vis spectroscopy, and photoluminescence spectroscopy. The experimental results confirmed that the CdS nanocrystalline existed in the composite films, and cellulose matrix provided a confined medium for CdS particle growth in uniform size. The CdS/RC composites showed narrow emission in photoluminescence spectra, and their optical absorbance in the UV range was higher than that of the cellulose film without CdS. This work provided a simple method to prepare cellulose functional materials in NaOH/urea aqueous solution.
Photoluminescence of CdS/RC nanocomposites and TEM image of CdS nanocrystals dispersed in RC matrix.
59 citations
TL;DR: In this article, the authors have successfully prepared biocompatible and biodegradable hollow microspheres with sizes between 2 and 5 μm using cyclohexane droplets as a template and the N-methylated chitosan (NMC) cross-linked with gultaraldehyde (GA) as the shell.
Abstract: We have successfully prepared biocompatible and biodegradable hollow microspheres with sizes between 2 and 5 μm using cyclohexane droplets as a template and the N-methylated chitosan (NMC) cross-linked with gultaraldehyde (GA) as the shell. The structure, morphology, and formation process of the hollow microspheres were characterized by FT-IR, 1H and 13C NMR, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results revealed that the microspheres exhibited a very smooth and hollow structure. This work confirmed that the hollow microspheres were accomplished by fabricating on the basis of chemical cross-linking on the surface of the emulsion droplets and by removing cyclohexane as core. The results from SEM and TEM indicated that the emulsion droplets covered with cross-linked NMC in the oil-in-water system aggregated together to form a precipitate of microspheres by coagulating with acetone. Moreover, the cross-linked NMC on the surface of the microspheres continuously cu...
TL;DR: In this paper, the distribution of substituents within anhydroglucose units (AGU) was examined by 13C NMR, and it was found that the relative reactivity of the hydroxyl groups within AGU and the new hyroxyl group was in the order C-x > C-6 > C −2 > C−3, an analogous functionalization pattern as HEC obtained by the heterogeneous slurry process.
Abstract: The 6 wt.% NaOH/4 wt.% urea aqueous solution was proved to be an aqueous non-derivatizing solvent for cellulose by 13C NMR. O-(2-hydroxyethyl)cellulose (HEC) was prepared by a totally homogeneous hydroxyethylation of cellulose using this new solvent for the first time, and the distribution of substituents within anhydroglucose units (AGU) was examined by 13C NMR. It was found that the relative reactivity of the hydroxyl groups within AGU and the new hydroxyl group was in the order C-x > C-6 > C-2 > C-3, an analogous functionalization pattern as HEC obtained by the heterogeneous slurry process. The ethylene oxide efficiency in this homogeneous etherification reaction was 20 – 30%.
TL;DR: In this article, the diffusion of glucose and a series of poly(ethylene glycol)s (PEG, average molecular weight = 200, 600, 1000, 10000) in agarose gels (in the range of 0.5−3%, w/w) have been studied with a novel refractive index method developed in our laboratory.
Abstract: The diffusion of glucose and a series of poly(ethylene glycol)s (PEG, average molecular weight = 200, 600, 1000, 10000) in agarose gels (in the range of 0.5−3%, w/w) have been studied with a novel refractive index method developed in our laboratory. The change of the gel refractive index caused by the change of the diffusing solute concentration in the gel during the diffusion process enables the effective solute diffusion coefficients to be computed. The change in glucose concentration in agarose gel with the diffusion distance and the diffusion kinetics of glucose in agarose gels reveal that glucose diffuses freely within these gel matrixes with a high diffusion coefficient ∼6 × 10-10 m2/s for 0.5% and 1.5% agarose gels. However, the diffusion coefficients of PEGs in the gel are generally in the range of (0.7−5.9) × 10-10 m2/s and decrease with an increase in the network density (higher agarose gel concentration) and/or in the molecular weight of the diffusing solutes. It is observed that the molecular ...
TL;DR: The results revealed that the PU/BS films possessed much higher optical transmittance and tensile strength than the pure PU film, and the interaction between the PU and the BS with relatively low M(w) was stronger than that with high M( w).
TL;DR: Results revealed that Pi‐PCM3‐I existed as an extended flexible chain in 0.25 M LiCl/Me2SO, and its sulfated derivative existed as a semistiff chain in0.15 M NaCl aqueous solution; this suggests promising industrialization of Poria cocos polysaccharides.
Abstract: From Poria cocos mycelia yielded via a pilot scale facility-fermentation tank, a water-insoluble (1-->3)-alpha-D-glucan coded as Pi-PCM3-I was isolated by extraction with 0.5 M NaOH/0.01 M NaBH(4) aqueous solution. Nine fractions from F1 to F9 with a weight-average molecular mass (M(w)) range from 7.75 x 10(4) to 57.3 x 10(4) were prepared from the Pi-PCM3-I sample by a nonsolvent addition method. The fractions were reacted with chlorosulfonic acid-pyridine complex to product water-soluble sulfated derivatives coded as S1 to S8 with M(w) from 2.36 x 10(4) to 14.5 x 10(4) and degree of substitution (DS) of 0.86-1.38. M(w), z-average radius of gyration (s(2) (z) (1/2)), the second virial coefficient (A(2)), and the intrinsic viscosity ([eta]) of the native and sulfated Pi-PCM3-I were measured by laser light scattering (LLS), size-exclusion chromatography combined with LLS (SEC-LLS), and viscometry at 25 degrees C. The Mark-Houwink equations for Pi-PCM3-I in 0.25 M LiCl/dimethylsulfoxide (DMSO) (Me(2)SO) and for its sulfated derivative in 0.15 M NaCl aqueous solution at 25 degrees C were established to be [eta] = 1.33 x 10(-2) M(w) (0.75+/-0.01) (mL g(-1)) and [eta] = 1.46 x 10(-4) M(w) (1.13+/-0.01) (mL g(-1)), respectively. On the basis of theories for a wormlike cylinder model, the conformational parameters of the native and sulfated Pi-PCM3-I were calculated to be 760 +/- 50 and 1060 +/- 30 nm(-1) for the molar mass per unit contour length (M(L)), 6.3 +/- 0.5 and 13.1 +/- 1 nm for the persistence length (q), and 14.9 +/- 0.2 and 31.8 +/- 1 for the characteristic ratio (C( proportional, variant)), respectively. The results revealed that Pi-PCM3-I existed as an extended flexible chain in 0.25 M LiCl/Me(2)SO, and its sulfated derivative existed as a semistiff chain in 0.15 M NaCl aqueous solution. Furthermore, Pi-PCM3-I possessed similar structure and molecular parameters to wc-PCM3-I from a rotary shaker; this suggests promising industrialization of Poria cocos polysaccharides.
TL;DR: In this article, anionic waterborne polyurethane (WPU) was mixed with soy protein isolate (SPI) in an aqueous dispersion at room temperature, and the resulting sheets containing about 60 % SPI were characterized with infrared spectroscopy, scanning electron microscopy, atomic force microscopy and tensile testing, and biodegradation testing of the sheets was performed in a mineral salt medium containing microorganisms.
Abstract: With anionic waterborne polyurethane (WPU) as a plasticizer and ethylene glycol diglycidyl ether (EGDE) as a crosslinker, we successfully prepared crosslinked soy protein isolate (SPI) plastics. Anionic WPU was mixed with SPI and EGDE in an aqueous dispersion at room temperature. The mixed aqueous dispersion was cast and cured, and the obtained material was pickled and hot-pressed to produce the crosslinked SPI/WPU sheets. The resulting sheets containing about 60 wt % SPI were characterized with infrared spectroscopy, scanning electron microscopy, atomic force microscopy, dynamic mechanical analysis, and tensile testing, and biodegradation testing of the sheets was performed in a mineral salt medium containing microorganisms. The results revealed that the crosslinked SPI/WPU plastics with EGDE concentrations of 2–4 wt % possessed high miscibility, good mechanical properties, and water resistivity. In addition, the crosslinked sheets could be biodegraded, and the half-life of the biodegradation for a sheet crosslinked with 3 wt % EGDE was calculated to be less than 1 month. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 465–473, 2005
TL;DR: The results indicated that the preparative SEC has good fractionation efficiency in both organic solvent and alkaline aqueous solution for the various polymers.
TL;DR: In this article, the structure and properties of the blend fibers were studied with the aids of infrared spectra (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM).
Abstract: Water‐soluble chitin (half‐deacetylated chitin) was prepared from chitosan by N‐acetylation with acetic anhydride. Alginate/water‐soluble chitin blend fibers were prepared by spinning their mixture solution through a viscose‐type spinneret into a coagulating bath containing aqueous CaCl2 and ethanol. The structure and properties of the blend fibers were studied with the aids of infrared spectra (IR), X‐ray diffraction (XRD) and scanning electron microscopy (SEM). structure analysis indicated good miscibility existed between alginate and water‐soluble chitin, due to the strong interaction from the intermolecular hydrogen bonds and electrostatic interactions. Best values for the dry tensile strength and breaking elongation were obtained when the water‐soluble chitin content was 30 wt%. The wet tensile strength and breaking elongation decreased with the increase of water‐soluble chitin content. The introduction of water‐soluble chitin in the blend fiber can improve the water‐retention properties of the blend...
TL;DR: In this article, two semi-interpenetrating polymer network (semi-IPN) films, coded as PUNT and PUN, have been prepared from amorphous nitrochitosan (NCH) and semicrystalline poly(ester-urethane) (PU) cross-linked to the hydroxy groups of tris(hydroxymethyl)propane (TMP) and NCO groups of PU prepolymer, respectively, by a casting method.
TL;DR: In this paper, a series of transparent materials with semi-interpenetrating polymer networks (semi-IPNs) from castor-oil-based polyurethane (PU) and benzyl starch (BS) were successfully prepared.
Abstract: We successfully prepared a series of transparent materials with semi-interpenetrating polymer networks (semi-IPNs) from castor-oil-based polyurethane (PU) and benzyl starch (BS). The miscibility, morphology, and properties of the semi-IPN films were investigated with attenuated total reflection/Fourier transform infrared spectroscopy, differential scanning calorimetry, dynamic mechanical thermal analysis, scanning electron microscopy, wide-angle X-ray diffraction, electron spin resonance (ESR), ultraviolet–visible spectroscopy, and tensile testing. The results revealed that the semi-IPN films had good or certain miscibility with BS concentrations of 5–70 wt % because of the strong intermolecular interactions between PU and BS. With an increase in the concentration of BS, the tensile strength and Young's modulus of the semi-IPN materials increased. The ESR data confirmed that the segment volume of PU in the semi-IPNs increased with the addition of BS; that is, the chain stiffness increased as a result of strong interactions between PU and BS macromolecules. It was concluded that starch derivatives containing benzyl groups in the side chains more easily penetrated the PU networks to form semi-IPNs than those containing aliphatic groups, and this led to improved properties. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 603–615, 2005
TL;DR: A water-soluble heteropolysaccharide ac-PCM0 from Poria cocos was successfully fractionated using a preparative size exclusion chromatography column, and their weight-average molecular mass was characterized by analytical SEC combined with laser light scattering (SEC-LLS).
Abstract: A water-soluble heteropolysaccharide ac-PCM0 from Poria cocos was successfully fractionated using a preparative size exclusion chromatography (SEC) column, and their weight-average molecular mass (M(w)) was characterized by analytical SEC combined with laser light scattering (SEC-LLS). The results indicate that the fractions having relatively high M(w) exhibited higher inhibition ratio in vivo antitumor activity than those having M(w) below 3.29 x 10(4). However, the relatively low molecular mass was beneficial to the in vitro antitumor activity. Moreover, ac-PCM0 has a significantly higher enhancement ratio of the body weight than 5-fluorouracil, and its 50% lethal dose is above 1250 mg/kg, indicating a nontoxic nature.
TL;DR: In this article, two kinds of water-insoluble polysaccharides (GM5-1 and GM6-1) were isolated from the mycelium of Ganoderma tsugae with 0.5 m NaOH aqueous solution at 25 and 65 ÂC successively.
TL;DR: In this article, a water-insoluble (1→3)-α-d -glucan (ab-PCM3-I) isolated from the Poria cocos mycelia by extracting with 0.5 sodium hydroxide was fractionated into ten fractions by non-solvent addition method in 0.25 m lithium chloride in dimethylsulfoxide.
TL;DR: In this article, a star-shape styrene-butadiene-styrene triblock copolymer SBS (802) was synthesized and fractionated into four fractions coded as 802-F1 (four arms), 802F2 (two arms), IEEE-F3 (one arm), and 802F4 by repeating fractional precipitation, and the structures and mechanical properties of the sheets were characterized by 1H-NMR, scanning electron microscope, wideangle X-ray diffractometer, tensile testing, and dynamic mechanical thermal analysis.
Abstract: A star-shape styrene–butadiene–styrene triblock copolymer SBS (802) was synthesized and fractionated into four fractions coded as 802-F1 (four arms), 802-F2 (two arms), 802-F3 (one arm), and 802-F4 by repeating fractional precipitation. Their weight-average molecular weight (Mw) was measured by size-exclusion chromatography combined with laser light scattering to be 16.0 × 104, 8.2 × 104, 4.3 × 104, and 1.19 × 104, respectively. The samples were, respectively, compression-molded and solution-cast to obtain the sheets coded as 802C, 802-F1C, 802-F2C, and 802S, 802-F1S, 802-F2S. The structures and mechanical properties of the sheets were characterized by 1H-NMR, scanning electron microscope, wide-angle X-ray diffractometer, tensile testing, and dynamic mechanical thermal analysis. The results indicated that the compression-molded 802-F1C exhibited the higher tensile strength (σb, 28.4 MPa) and elongation at break (eb, 1610%), and its optical transmittance is much higher than those of 802C and 802-F2C. This work revealed that the star-shape SBS with four arms could be helpful in the enhancement of the properties as a result of good miscibility of the compression-molded SBS sheets. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 832–840, 2005
TL;DR: In this paper, the results of TEM and X-ray diffraction revealed disperse silicates and a strong interaction between the terpolymer matrix and clay in the B-M nanocomposites.
Abstract: Styrene-isoprene-butadiene rubber/montmorillonite nanocomposites were synthesized by the addition of toluene into clay and living anionic polymerization. These silicate layers (B-M) were exfoliated within 30 min after polymerization initiation, whereas the layers in the nanocomposites prepared without using toluene (A-M) were only partially exfoliated and not well-dispersed in the matrix. The results of TEM and X-ray diffraction revealed disperse silicates and a strong interaction between the terpolymer matrix and clay in the B-M nanocomposites. The B-M-exfoliated nanocomposites exhibited higher decomposition and glass transition temperatures, storage moduli, tensile strengths and elongations at the break than those of the pure terpolymer and A-M. With an organophilic montmorillonite (OMMT) content of 3 wt.-%, the exfoliated nanocomposite exhibited the best thermal stability and mechanical properties. In addition, GPC and 1 H NMR results showed that the introduction of OMMT caused a slight increase in the M w of terpolymer, but hardly affected the microstructure of the terpolymer independent of the preparation method. Thus, the addition of toluene plays an important role in enhancing the dispersion of OMMT, which leads to the improvement of the structure and properties of the B-M nanocomposites.
TL;DR: In this paper, the structure and properties of the blend fibers were studied with the aid of infrared spectra (IR), scanning electron micrography (SEM), x-ray diffraction (XRD), and thermogravimetric analysis (TGA).
Abstract: Alginate and poly(vinyl alcohol) blend fibers were prepared by spinning their solution through a viscose‐type spinneret into a coagulating bath containing aqueous CaCl2 and ethanol. The structure and properties of the blend fibers were studied with the aid of infrared spectra (IR), scanning electron micrography (SEM), x‐ray diffraction (XRD), and thermogravimetric analysis (TGA). Mechanical properties and water‐retention properties were measured. The best values of the tensile strength of blend fibers, 13.57 cN/tex in the dry state and 3.02 cN/tex in the wet state, respectively, were obtained when the poly(vinyl alcohol) content was 10wt%. The breaking elongation and water‐retention values (WRV) of blend fibers increase as the amount of poly(vinyl alcohol) is raised. Structure analysis indicated that there was strong interaction and a certain level of miscibility between the alginate and poly(vinyl alcohol) molecules.
TL;DR: Seven lentinan fractions of various weight‐average molecular weights (Mw), ranging from 1.45 × 105 to 1.13 × 106 g mol−1 were investigated by static light scattering and viscometry in 0.1M NaOH solution with a certain degree of expansion due to the electrostatic repulsion from the interaction between the OH− anions and lentInan molecules.
Abstract: Seven lentinan fractions of various weight-average molecular weights (M w ), ranging from 1.45 x 10 5 to 1.13 x 10 6 g mol - 1 were investigated by static light scattering and viscometry in 0.1M NaOH solution at 25°C. The intrinsic viscosity [η] - M w and radius of gyration (s 2 ) 1 / 2 z -M w relationships for lentinan in 0.1M NaOH solution were found to be represented by [η] = 5.1 × 10 - 3 M 0 . 8 1 w cm 3 g - 1 and (s 2 ) 1 / 2 z = 2.3 × 10 - 1 M 0 . 5 8 w nm, respectively. Focusing on the effects of the M w polydispersity with the Schulz-Zimm distribution function, the data of M w , (s 2 ) 1 / 2 z , and [η] was analyzed on the basis of the Yoshizaki-Nitta-Yamakawa theory for the unperturbed helical wormlike chain combined with the quasi-two-parameter (QTP) theory for excluded-volume effects. The persistence length, molecular weight per unit contour length, and the excluded-volume strength were determined roughly to be 6.2 nm, 980 nm - 1 , and 0.1, respectively. Compared with the theoretical value calculated by the Monte Carlo model, the persistence length is longer than that of the single (1 → 3)-β-D-glucan chain. The results revealed that lentinan exists as single-stranded flexible chains in 0.1M NaOH solution with a certain degree of expansion due to the electrostatic repulsion from the interaction between the OH anions and lentinan molecules.
TL;DR: In this article, ion exchange beads were prepared from cellulose and alginate in 6.5% NaOH/4.4% urea aqueous solution by using an emulsion phase separation method.
Abstract: Our previous work has proved that mechanical properties of a blending alginate with cellulose was significantly enhanced in a wet state and maintained its biodegradability. In this article, ion‐exchange beads were prepared from cellulose and alginate in 6 wt% NaOH/4 wt% urea aqueous solution by using an emulsion phase separation method. The structure and morphology of the beads were characterized by scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectra, and the adsorption behaviors to Cd2+ and Cu2+ ions were measured by atomic absorption spectrometry (AAS). The effects of pH, adsorption time, ion concentration, temperature, and reusability of the beads on the adsorbed amount of Cd2+ and Cu2+ ions in aqueous solution were investigated by a batch method. The results indicated that the beads had a spherical shape, with ∼4–20 µm of diameter and relatively high ion‐exchange capacity (3.81 mmol g−1). The combined action of Cd2+ and Cu2+ ions on beads generally was found to be...
TL;DR: The experimental results revealed that UBS2 films exhibit stronger interfacial attraction and better phase mixing than the UES films, as a result of specific interactions between the PU hard segments and BS2 phenyl groups.
Abstract: Cornstarch derivative (ES), prepared using diethyl sulfate as an etherifying reagent, was blended with castor oil-based polyurethane (PU) prepolymer to obtain a series of semi-interpenetrating polymer network (semi-IPN) materials, named as UES films. Simultaneously, other kinds of semi-IPN (UBS2) were prepared from PU and benzyl starch (BS2) to compare the effects of the substitute groups. The differences in the miscibility and properties of the two series of materials were investigated using attenuated total reflection Fourier transform infrared spectroscopy, atomic force microscopy, dynamic mechanical thermal analysis, ultraviolet-visible spectroscopy, water-sensitivity and tensile testing. The experimental results revealed that UBS2 films exhibit stronger interfacial attraction and better phase mixing than the UES films, as a result of specific interactions between the PU hard segments and BS2 phenyl groups. The optical transmittance, water-resistivity, tensile strength, and elongation at break of the UBS2 films were clearly higher than those of the UES films containing the same concentration of PU. In particular, the miscibility and properties of the UES film with 40 wt.-% ES, were very poor, whereas the semi-IPN films containing 70 wt.-% benzyl starch still had a certain miscibility and good properties. Therefore, the phenyl groups play an important role in the improvement of the miscibility and properties of the semi-IPN materials.
Patent•
02 Mar 2005
TL;DR: In this article, the preparation process of tuckahoe mycelium extracellular polysaccharide with antitumor activity is described, which has an obvious growth inhibiting effect on Sarcoma 180 implanted inside mouse body and no toxic side effect.
Abstract: The present invention relates to the preparation process of tuckahoe mycelium extracellular polysaccharide with antitumor activity. Wild tuckahoe is deep fermented in corn slurry culture medium of pH 5.0-6.0 inside high pressure sterilized fermentation tank, and the culture liquid is collected and spray dried to obtain coarse extracellular polysaccharide. The coarse extracellular polysaccharide is dissolved in distilled water, filtered, H2O2 decolorized, free protein eliminated via Sevag process, clear water dialyzed for 5-7 days, distilled water dialyzed for 3-5 days, decompression distilled and freeze dried to obtain pure extracellular polysaccharide. Intracorporeal active experiment shows that the water soluble heteropolysaccharide has obvious growth inhibiting effect on Sarcoma 180 implanted inside mouse body and no toxic side effect. Extracorporeal active experiment proves its obvious inhibiting effect on the proliferation of HL-60 and has no damage to health monkey kidney cell.