Showing papers by "Lina Zhang published in 2001"
TL;DR: In this article, 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.
Abstract: 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
239 citations
TL;DR: In this article, the dissolution of cellulose and the structure, transparency, and mechanical properties of regenerated cellulose (RC) films were investigated by 13C NMR, ultraviolet, and infrared spectroscopies; scanning electron microscopy; X-ray diffraction; and a strength test.
Abstract: Regenerated cellulose (RC) films having various viscosity-average molecular weights (Mη) ranging from 2.2 × 104 to 8.2 × 104 g/mol were prepared from cotton linters in 6 wt % NaOH/4 wt % urea aqueous solution by coagulation with 2 M acetic acid and 2% H2SO4 aqueous solution. The dissolution of cellulose and the structure, transparency, and mechanical properties of the RC films were investigated by 13C NMR, ultraviolet, and infrared spectroscopies; scanning electron microscopy; X-ray diffraction; and a strength test. The RC films exhibited the cellulose II crystalline form and a homogeneous structure with 85% light transmittance at 800 nm. 13C NMR spectroscopy indicated that the presence of urea in NaOH aqueous solution significantly enhanced the intermolecular hydrogen bonding between cellulose and the solvent, resulting in a higher solubility of cellulose and the complete transition of its crystalline form from I to II. The tensile strength (σb) of the RC films in the dry state increased with increasing ...
204 citations
TL;DR: It is postulated that the antitumoral effect of NSPs from the sclerotia of P. tuber-regium is probably host-mediated and cytocidal.
Abstract: Mushroom dietary fiber or nonstarch polysaccharides (NSPs) that were soluble in hot alkali and belonged to the β-glucan type were isolated from the sclerotia of an edible mushroom, Pleurotus tuber-regium. The mushroom NSPs were further separated into a number of fractions [hot alkali extracts (HAEs)] with weight-average molecular weights (Mw) ranging from 1 × 104 to 42.2 × 104. The HAE fractions [with Mw of (5.8−17.1) × 104] administered intraperitoneally at a dose of 20 mg/kg of body weight to BALB/c mice implanted with solid tumor Sarcoma 180 were found to be effective in inhibiting tumor proliferation with an inhibition ratio of ≥50%. In vitro experiments using human tumor cell lines HL-60 and HepG2 had shown that HAE fractions with Mw of (5.8−42.2) × 104 also had antiproliferative activity at three different concentrations (50, 100, and 200 μg/mL) toward the tumor cell lines tested. All HAE fractions did not inhibit the growth of a normal kidney cell line (Vero) from monkey. It is therefore postulat...
85 citations
TL;DR: In this paper, the structure and properties of the blend films were studied by infrared (IR) spectra, wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA).
Abstract: Blend films were prepared by blending 4 wt% sodium alginate and 5 wt% gelatin aqueous solutions and dried at room temperature for 2 days to obtain the transparent films. Their structures and properties were studied by infrared (IR) spectra, wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA). Significant changes in the shape and intensity of IR spectra absorption frequencies characteristic of either gelatin or sodium alginate were detected by IR analysis. The crystallinities of the blend films decreased with the increase of sodium alginate content. The thermal stability, mechanical properties of tensile strength, and breaking elongation of the blend films were improved by blending sodium alginate with gelatin. It is worth noting that the breaking elongation reached 16.6% when the weight ratio of sodium alginate to gelatin was 1:1, much higher than that of two components. The structure analysis indicated that the...
84 citations
TL;DR: In this article, Lentinus edodes in water were degraded into seven fractions of different molecular weights by ultrasonic irradiation, and the weight-average mole was calculated for each fraction.
Abstract: beta-(1 -->3)-D-glucan with (1 -->6) branching (L-FV-I) from Lentinus edodes in water was degraded into seven fractions of different molecular weights by ultrasonic irradiation. Weight-average mole ...
72 citations
TL;DR: In this paper, the effects of glycol content on the structure and properties of thermoplastic SPI were investigated by using infrared, X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and tensile test.
Abstract: Thermoplastic sheets prepared from soy protein isolate (SPI) with ethylene glycol (EG) as the plasticizer were obtained by compression molding under a pressure of 15 MPa at 150 °C. The effects of the glycol content on the structure and properties of thermoplastic SPI were investigated by using infrared, X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and tensile test. The results showed that, with increasing EG content, the tensile strength (σb) and Young's modulus decreased and breaking elongation (eb) increased. The water resistance of the thermoplastic sheet of SPI increased with an increase of the EG content and was much higher than that of thermoplastic starch sheets or a cellulose film. Further investigation were carried on the SPI sheet containing 50% EG, which displayed a maximum water resistance in boiling water, good mechanical properties (σb = 4.23 MPa and eb = 220%) caused by interaction of SPI with EG, and light transmittance of 82% at 800 nm owing to inter...
70 citations
TL;DR: In this article, semi-interpenetrating polymer networks (semi-IPNs) were synthesized from castor oil-based polyurethane (PU) and 20 wt % nitrokonjac glucomannan (NKGM) with weight-average molecular weights (Mw) from 2.86 × 104 to 14.1 × 104.
Abstract: Semiinterpenetrating polymer networks (semi-IPNs) were synthesized from castor oil-based polyurethane (PU) and 20 wt % nitrokonjac glucomannan (NKGM) with weight-average molecular weights (Mw) from 2.86 × 104 to 14.1 × 104. Results from the dynamic mechanical analysis, differential scanning calorimetry, wide-angle X-ray diffraction, and ultraviolet spectrometer showed that the semi-IPNs have a single broad α-relaxation peak, one glass transition, and higher optical transmittance (Tr) in the wavelength range of 400−800 nm than PU, suggesting good miscibility in the range of NKGM Mw used. Noted that tensile strength (σb) of the semi-IPNs films was much higher than that of films PU and NKGM, and the Tr, σb, and breaking elongation (eb) obviously increased with decrease of NKGM Mw from 8.44 × 104 to 4.75 × 104 (Tr = 88% at 800 nm, σb = 34 MPa, eb = 110%). This indicated that the NKGM with relatively lower Mw plays an important role in plasticizing, accelerating cure, and enhancement of intermolecular interact...
65 citations
TL;DR: In this paper, a series of casting films blended from starch and waterborne polyurethane (STPU) in aqueous solution were prepared, and the structure and properties of the films were investigated by infrared spectroscopy, ultraviolet spectrograph, scanning electron micrography, strength test, thermogravimetric analysis, and different scanning calorimetry.
Abstract: A series of casting films blended from starch and waterborne polyurethane (STPU) in aqueous solution were prepared. The structure and properties of the films were investigated by infrared spectroscopy, ultraviolet spectroscopy, scanning electron micrography, strength test, thermogravimetric analysis, and different scanning calorimetry. The results showed that the tensile strength and modules of air-dried STPU blend films increased with the increase of starch content, while elongation decreased. When starch content was in the range from 80 to 90 wt %, the blend films showed significantly higher tensile strength, breaking elongation, water resistivity, and light transmittance than that of pure starch film, resulting from the miscibility between starch and waterborne polyurethane. Moreover, the STPU films containing 90 wt % starch have higher thermal stability than pure waterborne polyurethane film, and their light transmittance was close to the polyurethane, due to the existence of a strong intermolecular hydrogen bonding between starch and polyurethane. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2006–2013, 2001
55 citations
TL;DR: In this article, the regenerated cellulose (RC)/alginic acid (AL) blend membranes were satisfactorily prepared from 6 wt % NaOH/4 wt% urea aqueous solution by coagulating with 5 Wt % CaCl2 aqueously solution, and then treated with 3 Wt% HCl, and they were investigated by scanning electron microscopy (SEM), IR and UV spectroscopes, X-ray diffraction, tensile tests, and thermogravimetric analysis (TGA).
Abstract: Regenerated cellulose (RC)/alginic acid (AL) blend membranes were satisfactorily prepared from 6 wt % NaOH/4 wt % urea aqueous solution by coagulating with 5 wt % CaCl2 aqueous solution, and then treated with 3 wt % HCl. Morphology, crystallinity, mechanical properties, and thermal stability of the membranes were investigated by scanning electron microscopy (SEM), IR and UV spectroscopes, X-ray diffraction, tensile tests, and thermogravimetric analysis (TGA). The RC/AL blends were miscible in all weight ratios of cellulose to alginate. The membranes have homogeneous mesh structures, and the mesh sizes of the blend membranes (200–2000 nm) significantly increased with increasing alginate content. The crystalline state of the AL membrane prepared from 6 wt % NaOH/4 wt % urea aqueous solution was broken completely, and the crystallinity of the blend membranes decreased with an increase of AL. Comparing with AL membranes, the tensile strength and breaking elongation of the blend membranes were obviously improved in dry and wet states. Therefore, the RC/AL blends offer a promising way of alginate as separate and functional materials used in the wet state. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 451–458, 2001
54 citations
TL;DR: Polyurethane-nitrolignin (PUNL), a new network polymer, was synthesized from a castor oil-based polyurethanes (PU) prepolymer and nitroligenin (NL) with a weight-average molecular weight of 20.6 × 104 and a content of 1.4-10% as mentioned in this paper.
Abstract: Polyurethane-nitrolignin (PUNL), a new network polymer, was synthesized from a castor oil based–polyurethane (PU) prepolymer and nitrolignin (NL) with a weight-average molecular weight of 20.6 × 104 and a content of 1.4–10%. The structure and miscibility of PUNL films prepared by solution casting were investigated by infrared spectroscopy and transmission electron microscopy. The results indicated that PUNL2 film, which had a 2.8% NL content, was the most miscible, and its tensile strength (σb) and breaking elongation (ϵb) were 2 times higher than that of PU film. The crosslink densities of PUNL films increased with the increase of NL content until about 3%, similar to the variety of the mechanical properties. Thermogravimetric analysis revealed that the thermal stability of PUNL films was slightly higher than that of PU. Covalent bonds occurred between PU prepolymer and the NL in the PUNL films, forming crosslink networks, which resulted in the enhancement of mechanical properties and thermal stability. NL has a far higher reactivity with PU than nitrocellulose. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1213–1219, 2001
53 citations
TL;DR: In this article, a novel blend films of konjac glucomannan (KGM) with gelatin were prepared by using the solvent-casting technique, and the structure and physical properties of the films were investigated by Fourier transform IR, wide angle X-ray diffraction, thermogravimetric analysis, differential thermal analysis, scanning electron microscopy (SEM), and strength tests.
Abstract: Novel blend films of konjac glucomannan (KGM) with gelatin were prepared by using the solvent-casting technique. Transparent blend films were obtained in all blending ratios of the two polymers. The structure and physical properties of the films were investigated by Fourier transform IR, wide angle X-ray diffraction, thermogravimetric analysis, differential thermal analysis, scanning electron microscopy (SEM), and strength tests. The results indicated that intermolecular interactions between the KGM and gelatin occurred that were caused by hydrogen bonding and the physical properties of the films largely depended on the blending ratio. The crystallinities of the blend films decreased with the increase of the KGM. The thermal stability and mechanical properties (tensile strength and elongation at break) of the films were improved by blending KGM with gelatin. It is worth noting that the blend films had a good tensile strength of 38 MPa when the KGM content in the blend films was around 30 wt %. The surface morphology of the blend films observed by SEM displayed a certain level of miscibility. Furthermore, the water absorbability of the blend films was also measured and discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 1596–1602, 2001
TL;DR: In this article, microcapsules of chitosan/sodium carboxymethyl cellulose (NaCMC) were successfully prepared using a novel method of emulation phase separation.
Abstract: Microcapsules of chitosan/sodium carboxymethyl cellulose (NaCMC) were successfully prepared using a novel method of emulation phase separation. Their structure and morphology were characterized by infrared spectroscopy (IR), scanning electron microscopy (SEM), and X-ray diffraction. Bovine serum albumin (BSA) was encapsulated in the microcapsules to test their release behavior. The swelling behavior, encapsulation efficiency, and release behavior of the microcapsules with different chitosan contents and pH conditions were investigated. The results indicated that the microcapsules have a high encapsulation efficiency (75%) and a suitable size (20–50 μm). The BSA in the microcapsules was speedily released at pH 7.2, namely, in intestinal fluid. The BSA release was reduced with increase of the chitosan content from 17 to 38% in the microcapsules. Acid-treated microcapsules have a compact structure, owing to a strong electrostatic interaction caused by —NH2 groups of chitosan and —COOH groups of CMC, and the encapsulated BSA was hardly released at pH 1.0, namely, in gastric juice. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 584–592, 2001
TL;DR: The conformational parameters of the glucan TM8 were found to be 408 (nm−1) for ML, 3.1 (nm) for q, and 16.8 for C∞, suggesting that the polysaccharide exists as a dense random‐coil chain in DMSO, due to branched structure.
Abstract: A water-insoluble polysaccharide (TM8) was isolated from sclerotium of Pleurotus tuber-regium by extraction with 0.5M NaOH aqueous solutions at 120 degrees C. Its chemical structure was confirmed by infrared, high performance liquid chromatography, gas chromatography, and (13)C NMR in dimethylsulfoxide (DMSO) to be composed of beta-(1 --> 3)-D-glucan backbone chain linked with a branched glucose, one out of every three glycosyl units being substituted at C6 position. The glucan TM8 in DMSO was fractionated by nonsolvent addition method into ten fractions, and the solution properties were studied by size exclusion chromatography combined with multiangle laser light scattering (SEC-MALLS) and viscometry in DMSO at 30 degrees C. The dependencies of intrinsic viscosity [eta] and radius of gyration [(s(2)(1/2)(z-2)] on weight-average molecular mass M(w) for this glucan were found to be [eta] = (9.24 +/- 0.2) x 10(-2)M(w)(0.51 +/- 0.02) (cm(3)g(-1)) and [(s(2)(1/2)(z-2)] = (3.67 +/- 0.3) x 10(-2)M(w)(0.56 +/- 0.02) (nm) in the range of M(w) from 1.07 x 10(4) to 77.4 x 10(4). Based on current theories for a wormlike chain, the conformational parameters of the glucan TM8 were found to be 408 (nm(-1)) for M(L), 3.1 (nm) for q, and 16.8 for C(infinity), suggesting that the polysaccharide exists as a dense random-coil chain in DMSO, due to branched structure.
TL;DR: In this article, the physical properties of the blend films from konjac glucomannan and sodium carboxymethylcellulose were investigated by using FT-infrared (FTIR), wide-angle X-ray diffraction (WAXD), differential thermal analysis (DTA), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and measurements of mechanical properties.
Abstract: The novel blend films of konjac glucomannan (KGM) and sodium carboxymethylcellulose (NaCMC) were prepared by casting the mixed polymer aqueous solutions. The physical properties of the blend films from konjac glucomannan and sodium carboxymethylcellulose were investigated by using FT-infrared (FTIR), wide-angle X-ray diffraction (WAXD), differential thermal analysis (DTA), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and measurements of mechanical properties. The experimental results showed that the occurrence of the interactions between KGM and NaCMC molecular chains through hydrogen bond formation, and the physical properties of the films largely depend on the blending ratio. The thermal stability, mechanical properties of both tensile strength, and elongation at break of the blend films were improved by blending KGM with NaCMC. The surface morphology of the films observed by SEM was consistent with the results mentioned above.
TL;DR: In this article, a mixture of soy protein isolate (SPI) with glycerin was compression-molded to obtain thermoplastic sheets, which exhibited a smooth and homogeneous structure.
Abstract: Commercial soy protein isolate (SPI) was fractionated into four fractions by an acidifying method from pH 5.7 to 4.5 with 2M HCl. A mixture of SPI with glycerin (50 g/100 g of dry SPI) was compression-molded to obtain thermoplastic sheets. The weight-average molecular weight (Mw) of the fractions, the structure, and the mechanical properties of the thermoplastic SPI sheets were investigated with light scattering, IR spectroscopy, wide X-ray diffraction patterns, differential scanning calorimetry, ultraviolet spectroscopy, scanning electron microscopy, and tensile testing. After heating compression, the SPI sheets were transparent and exhibited a smooth and homogeneous structure. Moreover, the crystallinity degree of the thermoplastic SPI was obviously higher than that of the premix before compression because of the formation of intermolecular hydrogen bonding. The Mw's of the fractions were 1.17 × 105 to 3.21 × 105, and they increased with increasing pH value in fractionation. The mechanical properties and water resistance (R) of the SPI sheets increased with increasing Mw of the SPI fractions. The tensile strength and breaking elongation of the SPI sheets with an Mw value of 3.21 ×105 were 5.7 MPa and 135%, respectively, and the R value was 0.54 after immersion in water for 15 days. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3373–3380, 2001
TL;DR: In this article, a tensile test and thermogravimetric analysis were performed on polyurethane (PU) films from castor-oil-based PU prepolymer with different hard-segment compositions and nitrolignin (NL) were synthesized.
Abstract: Segmented polyurethane (PU) films from castor-oil-based PU prepolymer with different hard-segment compositions and nitrolignin (NL) were synthesized. Diisocyanates (DIs), such as 2,4-tolylene DI (TDI) and 4,4′-diphenylmethane DI (MDI), 1,4-butanediol (BDO) as a chain extender, and trimethanol propane (TMP) as a crosslinker were used to obtain PU films containing NL (UL) which were named as UL–TB for TDI and BDO, UL–TT for TDI and TMP, UL–MB for MDI and BDO, and UL–MT for MDI and TMP, respectively. The mechanical properties and thermal stability of the films were characterized by a tensile test and thermogravimetric analysis, respectively. The MDI-based UL films exhibited a higher tensile strength (σb) and thermal stability than TDI-based UL. However, the recoverability of the TDI-based UL films was better than that of others. The UL films with TMP (UL–TT and UL–MT) had higher σb and lower breaking elongation (ϵb) than the UL films with BDO (UL–TB and UL–MB), caused by enhancement in the crosslinking network of hard segments and microphase separation between soft and hard segments. The values of σb and ϵb of the UL films that contained NL were much higher than those of the PU films, which indicates that the introduction of NL increased the interaction between hard segments by crosslinking. The hydrogen bonding in the UL films was studied by infrared spectroscopy, which indicated that MDI favored the formation of hydrogen bonds, especially in the ordered domain. Differential scanning calorimetry, dynamic mechanical analysis, and wide-angle X-ray diffraction indicated that the UL films were compatible as a whole, but microphase separation existed between soft and hard segments and significantly affected the mechanical properties. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3251–3259, 2001
TL;DR: In this article, a series of compression-molded sheets coded as STPU were prepared by mixing thermoplastic starch (TPS) with the desired amount of WPU, and the properties and structure of the sheets TPS, STPU and WPU were investigated by tensile tests, wide X-ray diffraction patterns (WXRDPs), differential scanning calorimetry, infrared spectroscopy, ultraviolet spectrograph, and scanning electron microscopy.
Abstract: A polyester-type waterborne polyurethane (WPU) was synthesized with 2,4-tolylene diisocyanate (TDI), poly-1,4-butylene glycol adipate (PBA), and 2,2-bis-(hydroxylmethyl) propionic acid (DMPA). A series of compression-molded sheets coded as STPU were prepared by mixing thermoplastic starch (TPS) with the desired amount of WPU. The properties and structure of the sheets TPS, STPU, and WPU were investigated by tensile tests, wide X-ray diffraction patterns (WXRDPs), differential scanning calorimetry, infrared spectroscopy, ultraviolet spectroscopy, and scanning electron microscopy. The results showed that the tensile strength, breaking elongation, and water resistance of the STPU sheets were all higher than that of TPS, when the WPU content was in the range from 5 to 30 wt %. The STPU sheets were found to have higher crystallinity than WPU and amorphous TPS and slightly lower light transimitance than TPS, suggesting that partially recrystallized starch formed. The WPU plays an important role in the formation...
TL;DR: In this article, the structure and properties of the cellulose/casein blend membranes were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), wide-angle X-ray diffraction, differential scanning calorimetry, and a tensile test.
Abstract: Cellulose membranes and cellulose/casein blend membranes were successfully prepared from a new solvent system (6 wt % NaOH/4 wt % urea aqueous solution) by coagulation with a sulfuric acid aqueous solution. The structures and properties of the membranes were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), wide-angle X-ray diffraction, differential scanning calorimetry, and a tensile test. The experimental results showed that the suitable coagulation condition was 5 wt % H2SO4 for 5 min. When the casein content of the mixture was less than 15 wt %, the blend membranes were miscible because of the interactions between the hydroxyl groups of cellulose and the peptide bonds of casein. The blend membranes with 10 wt % casein had good miscibility, higher crystallinity, and the highest mechanical properties and thermal stability. In this case, the tensile strength and breaking elongation of the blend membranes were 109 MPa and 16%, respectively, and its pore size, obtained by SEM, was 290 nm, which suggests that the blend membranes provide a potential application for the field of separation technology. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3260–3267, 2001
TL;DR: In this paper, a semi-interpenetrating polymer network (semi-IPN) coded as PUNK was successfully synthesized from castor oil-based polyurethane (PU) prepolymer and 10-40 wt % nitrokonjac glucomannan (NKGM) containing a degree of substitution of 2.4 and a weight-average molecular weight of 4.75 × 104.
Abstract: New semi-interpenetrating polymer networks (semi-IPNs) coded as PUNK were successfully synthesized from castor oil-based polyurethane (PU) prepolymer and 10–40 wt % nitrokonjac glucomannan (NKGM) containing a degree of substitution of 2.4 and a weight-average molecular weight of 4.75 × 104. The semi-IPN sheets that were 100 μm thick were cured more speedily than PU, with curing times of 5 h for PUNK and 16 h for PU at 50–70°C. The structure and miscibility of the semi-IPN sheets were studied by Fourier transform infrared spectroscopy, ultraviolet spectroscopy, and scanning electron microscopy. The results showed that a strong intermolecular interaction caused by hydrogen bonding between NKGM and PU exists in PUNK, resulting in good miscibility. When the NKGM content of the semi-IPNs sheets was 20 wt %, the tensile strength and light transmittance were obviously higher than that of the PU sheets. The NKGM in the semi-IPN sheets plays an important role not only in accelerating the cure but also in improving the mechanical properties and biodegradability. As a new material prepared from renewable resources, PUNK has potential applications because of its biodegradability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2076–2083, 2001
TL;DR: In this paper, a mixture of konjac glucomannan (KGM) and poly(vinylpyrrolidone) (PVP) was prepared by using a conventional solvent-casting technique and dried at room temperature.
Abstract: Blend films of konjac glucomannan (KGM) and poly(vinylpyrrolidone) (PVP) were prepared by using a conventional solvent-casting technique and dried at room temperature. The structure and physical properties were studied by infrared spectroscopy (IR), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscope (SEM), and by measurement of mechanical properties. The changes of carbonyl stretching bands of KGM and PVP and hydroxyl stretching region of KGM were detected by FTIR analysis. WAXD analysis revealed that the film KP-2 got the lowest crystallinity of all the films. The tensile strength and breaking elongation of the blend films reaches the maximum value at 10 wt % PVP content. The DTA curves indicated the existence of interaction between two kinds of macromolecules. Higher thermal stability was attained by konjac glucomannan through blending with PVP. These improvements are attributable to the existence of a certain degree of interaction between KGM and PVP molecules resulted from intermolecular hydrogen bonds. Air surface morphology of the films observed by SEM was consistent with the results mentioned above. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1049–1055, 2001
TL;DR: In this paper, the properties of the blend films of konjac glucomannan (KGM) and polyacrylamide (PAAm) were investigated by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and measurement of mechanical properties.
Abstract: The blend films of konjac glucomannan (KGM) and polyacrylamide (PAAm) were prepared by using the solvent-casting technique. Transparent blend films were obtained in all blending ratios. The physical properties of the films were investigated by Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and by measurement of mechanical properties. The results indicated the occurrence of intra- and intermolecular interactions of the pure components, as well as the intermolecular interactions between KGM and PAAm through hydrogen bond formation. The thermal stability and mechanical properties of both tensile strength and elongation at break of the films were improved by blending KGM with PAAm. It was worth noting that the blend film had the greatest tensile strength when the KGM content in the blend films was around 30 wt %. Surface morphology of the films observed by SEM was consistent with the above-noted results. Furthermore, the water absorbability of the blend films was also investigated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 882–888, 2001
TL;DR: In this article, the structure and physical properties of the resulting blend films were analyzed by FT-infrared spectra (FT-IR), wide angle X-ray diffraction (WAXD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and by tensile tester.
Abstract: In this article, blend films were prepared by blending 2 wt% chitosan acetate solution with 2 wt% polyacrylamide (PAAm) aqueous solution. The structure and physical properties of the resulting blend films were analysized by FT-infrared spectra (FT-IR), wide angle X-ray diffraction (WAXD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and by tensile tester. The results showed the occurrence of intermolecular interactions between chitosan and polyacrylamide through hydrogen bond formation. The thermal stability, and mechanical properties were improved by blending chitosan with polyacrylamide. It was worth noting that the blend film exhibited the greatest tensile strength 68 MPa and highest thermal stability when the polyacrylamide content in the blends was around 20 wt%. The results from SEM were consistent with the results above. Meanwhile, the water absorbability of the blend films was also discussed.
TL;DR: In this paper, two semi-interpenetrating polymer networks (semi-IPNs) based on trihydroxyl methylpropane-polyurethane (T-PU) or castor oil-polyuresan (C-PU), were prepared by curing the mixed solution of the PU prepolymer and nitrochitosan (NCH).
Abstract: Two semiinterpenetrating polymer networks (semi-IPNs) based on trihydroxyl methylpropane–polyurethane (T-PU) or castor oil–polyurethane (C-PU) were prepared by curing the mixed solution of the polyurethane prepolymer and nitrochitosan (NCH). During the curing process, crosslinking and grafting reaction between the molecules of the PU prepolymer and NCH occurred, because of the high reactivity of remaining hydroxyl groups in the NCH with NCO groups of PU. The structure of the original semi-IPN sheets and the sheets treated with acetone were studied by infrared, 13C-NMR, scanning electron microscopy, and dynamic mechanical analysis, showing interpenetration of NCH molecules into the PU networks. When nitrochitosan content (CNCH) was lower than 10 wt %, the semi-IPN sheets T-PU and C-PU had higher density and tensile strength (σb) than the systems with CNCH more than 20%. The trihydroxymethyl propane-based PU reacted more readily with nitrochitosan to form the semi-IPNs than castor oil-based PU. The semi-IPN coatings T-PU and C-PU were used to coat cellophane, resulting in intimate interfacial bonding. The mechanical strength and water resistivity of the cellophane coated with T-PU coating were improved remarkably. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3109–3117, 2001
TL;DR: In this article, a linear β-(1→3)-d-glucan PCM3 (pachyman), a major polysaccharide in Poria cocos mycelia, formed aggregates in aqueous solution or dimethyl sulfoxide (DMSO) with absorbed moisture.
Abstract: A linear β-(1→3)-d-glucan PCM3 (pachyman), a major polysaccharide in Poria cocos mycelia, formed aggregates in aqueous solution or dimethyl sulfoxide (DMSO) with absorbed moisture, thereby considerably complicating its fractionation and study of solution properties. In this work, the pachyman PCM3 having narrow polydispersity (M w/M n = 1.9) was carefully fractionated by a preparative size exclusion chromatography (SEC) using dehydrated DMSO as the mobile phase. The weight-average molecular mass M w and intrinsic viscosity [η] of the fractions were measured by static and dynamic laser light scattering, SEC combined with light scattering, and viscometry in DMSO at 25°C, thus eliminating the aggregation. The Mark-Houwink equation for the pachyman in DMSO is established to be: [η] = 6.79 × 10−4 M w 0.95 (mL/g) in the M w range from 1.2 to 3.5 × 105. The characteristic ratio C ∞ of the PCM3 in DMSO at 25°C, from light scattering by using Flory theory, was obtained to be 10.1, thus indicating that it behaves a...
TL;DR: In this paper, a series of O-2-[2-(2-(methoxyethoxy)ethoxy] acetyl celluloses with different degree of substitution (DS) values was synthesized by a homogeneous reaction of cellulose with 2-[2]-2-...
Abstract: In this article, a series of O-2-[2-(2-methoxyethoxy)ethoxy] acetyl celluloses with different degree of substitution (DS) values was synthesized by a homogeneous reaction of cellulose with 2-[2-(2- ...
TL;DR: In this article, the water-soluble coating, including the semi-interpenetrating polymer networks (IPNs) formed by polyurethane (PU) with acrylamide grafted konjac glucomannan (KGM), was prepared and coated to the regenerated cellulose film that was prepared from 7 wt.-% ramie cellulose cuoxam to give water-resistant films.
Abstract: The water-soluble coating, including the semi-interpenetrating polymer networks (IPNs) formed by polyurethane (PU) with acrylamide grafted konjac glucomannan (KGM), was prepared and coated to the regenerated cellulose film that was prepared from 7 wt.-% ramie cellulose cuoxam to give water-resistant films. The structure and properties of the coated films were studied by infrared, differential thermal analysis, transmission electron microscopy, ultraviolet, and tensile rength test. It was shown that there was strong interaction between the regenerated cellulose (RC) film and the semi-IPN coating layer at the interface, where covalent bonds and hydrogen bonds formed between ─NCO groups in the coating and ─OH groups in the RC film. The tensile strength and water resistances evaluated from the mechanical parameters of the coated films were much higher than those of the uncoated films.