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  • 1
    Electronic Resource
    Electronic Resource
    Multiphase materials with lignin. VIII. Interpenetrating polymer networks from polyurethanes and polymethyl methacrylate (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 2813-2828 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Several types of interpenetrating polymer networks (IPNs) from polyurethane/polymethyl methacrylate (LPU/PMMA) on the basis of lignin were prepared. All composites were judged to possess two phase morphology. The composition and the presence of crosslinking were found to influence the thermal and mechanical properties of the solvent-cast films. The mechanical properties were assessed by dynamic mechanical analysis and by tensile testing, and they were found to vary consistently with composition and the presence of crosslinks. The modulus behavior of the different IPNs could be explained by models which accounted for either dual phase continuity or phase inversion.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070411124
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  • 2
    Electronic Resource
    Electronic Resource
    Novel cellulose derivatives. I. Liquid crystal phase formation in tri-O-α-naphthylmethyl cellulose solutions (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 49 (1993), S. 1671-1678 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Tri-O-α-naphthylmethyl cellulose was prepared by homogeneous phase reaction using SO2-diethylamine (DEA)-dimethyl sulfoxide (DMSO) as the solvent system. Observations made by dynamic mechanical spectrometry and by cross-polarized optical microscopy revealed liquid crystalline behavior for the concentrated solutions of tri-O-α-naphthylmethyl cellulose in dimethylacetamide (DMAc). Experimental and calculated (predicted) critical volume fraction of the derivative, Vcp, did not show agreement. It is determined that Vcp is affected by bulky substituents on the cellulose backbone to some extent. © 1993 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070490920
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  • 3
    Electronic Resource
    Electronic Resource
    Intramolecular effects in cellulose mixed benzyl ethers blended with poly(ε-caprolactone) (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 58 (1995), S. 1063-1075 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Tri-O-benzyl cellulose, tri-O-p-fluorobenzyl cellulose, and a corresponding series of cellulose mixed benzyl ethers were synthesized and blended with poly(ε-caprolactone) (PCL). Mechanical and thermal analyses indicated that none of the cellulose benzyl ethers of the cellulose mixed benzyl ethers was miscible with PCL. However, there was evidence of a limited degree of compatibility that exhibited a dependence on the substituent ratio, or copolymer composition, of the cellulose mixed benzyl ethers. The weak interactions in these blends were found to be nonspecific, and thus the limited compatibility is thought to arise from intramolecular interactions within the cellulose mixed benzyl ethers. The treatment of cellulose mixed derivatives as copolymers and the potential use of intramolecular effects in cellulose derivative blending is discussed. © 1995 John Wiley & Sons, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070580613
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  • 4
    Electronic Resource
    Electronic Resource
    Cellulose-based fibers from liquid crystalline solutions. III. Processing and morphology of cellulose and cellulose hexanoate esters (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 48 (1993), S. 683-699 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Cellulose and a cellulose hexanoate ester (DS 0.69) exhibited liquid crystalline behavior in dimethylacetamide/lithium chloride and dimethylacetamide, respectively. The experimentally observed critical volume fraction (Vcp) of cellulose was lower than that predicted by Flory's theory, whereas the experimental and theoretical values of Vcp were within 70% of prediction for cellulose hexanoate. The Vcp value obtained for cellulose hexanoate was lower than that previously reported for cellulose acetate butyrate with a maximum degree of butyration (CAB-3). This indicates that bulky substituents may lower Vcp values. Fibers were spun from isotropic and anisotropic solutions of cellulose and cellulose hexanoate by a dry jet/wet spinning method. There was an increase in mechanical properties through the isotropic to anisotropic transition with moduli reaching 152 g/d (20.8 GPa) for cellulose fibers. The formation of cellulose fibers with high modulus at large extrusion rates and large takeup speeds (draw ratio) is explained with molecular organization prior to coagulation. This unexpected enhancement is attributed to the air gap that exists in the dry jet/wet spinning process. Similar improvements were not observed for cellulose hexanoate fibers. This is explained with incomplete development of liquid crystalline structure at the solution concentrations from which the fibers were spun. © 1993 John Wiley & Sons, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1993.070480411
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  • 5
    Electronic Resource
    Electronic Resource
    Chitin derivatives. I. Kinetics of the heat-induced conversion of chitosan to chitin (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 75-85 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The water-soluble solids comprised of the ionic complex between chitosan and acetic acid, chitosonium acetate, are converted into chitin by heating. The thermally-induced conversion of a water-soluble chitosonium acetate in film form into a water-insoluble chitin film was examined by thermal analysis (DMTA, TGA, DSC, and TMA) and by solid state 13C-NMR spectroscopy. Results indicate that tan δ-transitions occur at increasingly high temperatures, and over progressively wider temperature ranges, as the transformation progresses. Likewise, the storage modulus, log E′, increases as the chitosonium acetate film undergoes “cure” and converts to chitin. Cure kinetic parameters are obtained using the model proposed by Provder et al. modified for glass transition temperature (Tg). The results suggest the existence of two sequential first order reactions, an initial and a late cure reaction, having activation energies of approximately 15 and 21 kcal/mol, respectively. © 1996 John Wiley & Sons, Inc.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hydrogels from polysaccharides. I. Cellulose beads for chromatographic support (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 60 (1996), S. 63-73 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Cellulosic hydrogels in bead form were prepared by dropwise addition of cellulose solutions in N,N-dimethylacetamide (DMAc) and lithium chloride (LiCl) to azeotropic methanol or isopropanol as nonsolvent. Bead properties were examined in relation to cellulose solution concentration, viscosity, and molecular weight. Bead properties were defined in terms of solids content, flow characteristics, mechanical strength, bead size, and pore dimensions. Results suggest that (a) beads can be prepared with solids content ranging from 2 to 12 wt %, depending on solution concentration; (b) uniform spherical shapes require a viscosity range between 100 and 300 cS: (c) beads can be produced in different sizes, within the diameter range of 100 to 1,500 μm; (d) linear flow velocities of packed bead columns are in the range of 70 to 350 cm/min; and (e) pore sizes of beads vary between 8 to 200 Å. Beads with low cellulose concentration show a wide fractionation range of up to 200,000 g/mol for polyethylene oxide. © 1996 John Wiley & Sons, Inc.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Hydrogels from polysaccharides. II. Beads with cellulose derivatives (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 81-86 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The generation of hydrogels from solutions of cellulose ester derivatives of various types using an atomization device, in which the solution travels through air before phase inversion occurs in a nonsolvent, was unable to produce beads in spherical shape. Instead, irregularly shaped particles were formed. The cellulose derivatives included a series of cellulose esters with a high and low degree of substitution (DS) and with acyl substituents ranging in size from C3 to C12 (laurate). Starch was tested as a noncellulosic polysaccharide, and the list of cellulose derivatives included a fluorine containing ester. The formation of spherical hydrogel beads by this method became possible only when cellulose derivatives or starch were blended in solution with unmodified cellulose. The resulting beads had dynamic flow characteristics, for instance, linear velocity vs. pressure drop relationships, that closely followed the rule of mixing. An exception was cellulose laurate, which retained most of the strength of unblended cellulose even at 60% derivative content. The results suggest (a) that cellulose is needed for the formation of droplets with sufficiently high surface tension capable of withstanding the collision with the nonsolvent surface; (b) that cellulose derivatives require the presence of unmodified cellulose to attain sufficient gel strength; and (c) that waxy ester substituents provide the basis for hydrophobic interactions which contribute to gel strength retention. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Engineering plastics from lignin. I. Synthesis of hydroxypropyl lignin (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 1111-1123 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Hydroxypropylation of lignin in a batch reactor under alkaline conditions at 180°C was studied using propylene oxide (PO) by itself, and PO in combination with several ligninlike model compounds and with kraft lignin. While the PO homopolymerization rate increased rapidly at temperatures above 85°C, and was too fast to be determined accurately at 180°C, the addition of model compounds and lignin was found to delay homopolymerization in relation to the presence of ionizable functional groups. The observations are consistent with a reaction mechanism involving first order kinetics with regard to each alkoxide and PO concentrations. Where the reaction rates toward PO increase with increasing pKa values, the reaction sequence proceeds in the order of declining basicity. Thus lignins with high acidity were found to be subject to greater degrees of modification than those with more neutral character. This explains the earlier observed beneficial effect of lignin carboxylation on the properties of lignin-PO reaction mixtures.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1984.070290408
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  • 9
    Electronic Resource
    Electronic Resource
    Engineering plastics from lignin II. Characterization of hydroxyalkyl lignin derivativesThis study was financially supported by the National Science Foundation, Washington, D. C., under Grant No. PFR 79-13135; and by the USDA-SEA under Grant No. 59-2511-1-2-121-0. This manuscript is based, in part, on a paper presented at the International Symposium on Wood and Pulping Chemistry, held in Tsukuba Science City, Japan, May 23-27, 1983. (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 29 (1984), S. 1815-1830 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Several types of hydroxyalkyl lignin derivatives were synthesized from milled wood, organosolv, steam explosion, acid (H2SO4) hydrolysis, and kraft lignin with ethylene oxide, propylene oxide, and butylene oxide by either batch reaction in toluene at 180°C using KOH as catalyst, or in aqueous alkali at room temperature. The isolated derivatives were characterized in terms of their chemical structures by H-NMR and FT-IR spectroscopy. Thermal properties were determined by differential scanning calorimetry. Molecular weights were measured by gel permeation chromatography on polystyrene/lignin model compound calibrated high pressure μ-spherogel columns. Solubilities in various organic solvents spanning a solubility parameter (δ) range from 9.3 to 14.5 and a hydrogen bonding index (γ) range from 1.5 to 18.7 were tested using UV280 absorption of solutions of up to with degrees of substitution of between 1 and 2.6 (except for ethylene oxide derivatives which were higher) and with lignin contents of around 60%. The drastic reduction of glass transition temperature of between 50° and 100° is explained with increased free volume of the copolymer and with disruption of hydrogen bonds involving especially phenolic hydroxy groups. The greatly enhanced solubility in organic solvents indicates absence of the gel structure typical of network polymers. No molecular breakdown was observed as a consequence of oxyalkylation. The derivatives had molecular weights (Mw) of between 2000 and 50,000 at dispersity factors of between 2.5 and 25. The derivatives seem to constitute useful prepolymers for thermosetting engineering plastics.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1984.070290533
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  • 10
    Electronic Resource
    Electronic Resource
    Thermal and dynamic mechanical properties of hydroxypropyl cellulose films (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 36 (1988), S. 749-758 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) were used to characterize the morphology of solvent cast hydroxypropyl cellulose (HPC) films. DSC results were indicative of a semicrystalline material with a melt at 220°C and a glass transition at 19°C (T1), although an additional event was suggested by a baseline inflection at about 80°C (T2). Corresponding relaxations were found by DMTA. A secondary relaxation at -55°C was attributed to the interaction between hydroxyl groups of the polymer and residual diluent. The tan δ peak at T2 was found to arise from an organized phase, presumably from a liquid-crystal mesophase formed while in solution. Crosslinking with a diisocyanate increased the peak temperature of the two primary relaxations, and resulted in a more clearly defined peak for the T2 transition. From this behavior it was concluded that both T1 and T2 are similar to glass transitions (Tg's) associated with an amorphous component and a more highly ordered phase (due to a residual liquid crystal superstructure) in the HPC bulk.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1988.070360402
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