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  • 1
    Electronic Resource
    Electronic Resource
    Volume and heat capacity changes upon ionization of water, acetic acid, n-propylamine, and 4-methylimidazole in water and 8 M urea: consequences of ionization on properties of proteins (1984)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 88 (1984), S. 3348-3356 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j150659a043
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  • 2
    Electronic Resource
    Electronic Resource
    Phenol-formaldehyde resin curing and bonding under dynamic conditions (1996)
    Springer
    Wood science and technology 30 (1996), S. 423-442 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary To better understand the curing and bonding behavior of phenol-formaldehyde (PF) resin under dynamic conditions, flakeboards were manufactured either by conventional pressing at 7% or 12% mat moisture content or by steam injection pressing with 10 or 20 seconds steaming duration. Resin-impregnated glass-cloth samples and lap-shear tension specimens were embedded in the core of each flakeboard. After the flakeboards were pressed for various periods of times, the samples and specimens were quickly retrieved. The degree of resin cure was determined on the resin-impregnated glass-cloth samples by dynamic mechanical analysis. The bond strengths were measured from the lap-shear tension specimens on a mechanical testing machine. The results of resin curing and bonding were then correlated to the performance of the resin-bonded boards, which were evaluated by internal bond, modulus of rupture, modulus of elasticity, and thickness swelling. Resin curing and lap-shear bonding did not proceed simultaneously. In conventional pressing, the mat moisture content (MC) at 12% favored resin curing, but slightly retarded lap-shear bonding, as compared to 7%MC. In steam injection pressing, the rates of resin curing and lap-shear bond strength development were much faster for 20 seconds than for 10 seconds of steaming duration. Longer press times were needed to obtain boards with maximum strength in the 12%MC conventional pressing and the 20-s steam duration steam injection pressing than in those conditions where moisture content was lower or steam time was less. The need for longer press times must be attributed to higher internal vapor pressures and/or lower wood and resin component strengths, rather than to incomplete cure or bonding.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00244438
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  • 3
    Electronic Resource
    Electronic Resource
    The effects of temperature and humidity on phenol-formaldehyde resin bonding (1995)
    Springer
    Wood science and technology 29 (1995), S. 253-266 
    Details
    ISSN: 1432-5225
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Summary The effects of temperature and relative humidity on phenol-formaldehyde resin bonding were evaluated. Two flakes in a lap-shear configuration were bonded under an environment of controlled temperature (110 °C, 120 °C, 130 °C, 140 °C) and relative humidity (41%, 75%, 90%) for a series of time periods (0.25 to 16 min). The lap-shear specimens were then shear-tested on a mechanical testing machine and the results were used to establish a family of bond strength development curves at each temperature and level of relative humidity. At 110°C, the higher relative humidity appeared to retard resin bonding. The effects of relative humidity diminished as temperature increased to 140 °C. Bond strength development was chemical ratecontrolled. The rate of bond strength development at each relative humidity follows a first order reaction mechanism. The activation energy of resin-wood bonding, determined by bonding kinetics, was higher than that of resin alone, determined by differential scanning calorimetry. This comparison indicates that to form a strong resin-wood bond, a higher energy level might be required.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202085
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of weight average molecular mass of phenol-formaldehyde adhesives on medium density fiberboard performance (1998)
    Springer
    Holz als Roh- und Werkstoff 56 (1998), S. 155-161 
    Details
    ISSN: 1436-736X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: ) of phenol-formaldehyde (PF) adhesives on the performance of medium density fiberboard (MDF). To obtain different PF resins, a series of PF resoles were prepared by blending low (LMW) and high (HMW) resins in different proportions. Six blending ratios of LMW:HMW were chosen: 100:0, 80:20, 60:40, 40:60, 20:80, and 0:100. The prepared resins were characterized with size exclusion chromatography (SEC) for their determination and differential scanning calorimetery (DSC) for thermal cure kinetics. As the proportion of HMW was increased, and hence the viscosity of adhesives increased. The thermal curing kinetics of the blended resins obtained by DSC showed that total thermal energy (ΔH) and activation energy (Ea) of cure decreased with increasing resin as determined by SEC. Test result for a series of fiberboards prepared with the blended resins showed that the LMW:HMW blending ratio of 40:60 gave the highest internal bond (IB) strength. The optimum viscosity of PF resin was approximately 300 mPa.s. The maximum values of MOR and MOE were found at a blending ratio of 80:20 (LMW:HMW). The density profile indicated that MOR and MOE were influenced by the maximum density of the board surfaces while the IB correlated to the minimum density in the core regions of the board.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001070050289
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  • 5
    Electronic Resource
    Electronic Resource
    Thermodynamic study of poly(vinyl chloride)/polyester blends by inverse-phase gas chromatography at 120°C (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 24 (1986), S. 2565-2582 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polymer/polymer interaction parameters χ′23 have been measured at 120°C as a function of polymer concentration for six different poly(vinyl chloride)/linear aliphatic polyester blends. The technique used is inverse-phase gas chromatography with several molecular probes. The polymers investigated are poly(DL-lactide), poly(ethylene succinate), poly(ethylene adipate), poly(butylene adipate), poly(δ-valerolactone), poly(ε-caprolactone) and poly(hexamethylene sebacate). Probe/polymer interaction parameters χ12 and polymer/polymer interaction parameters χ′23 values are dependent upon the methylene to carbonyl ratio of the polyester, reaching a minimum for a value of 5, this ratio corresponding to poly(ε-caprolactone) blends. Results are interpreted in terms of pairwise interactions between carbonyl, methylene, and [CHCl] groups.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1986.090241113
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  • 6
    Electronic Resource
    Electronic Resource
    Temperature dependence of the interaction between n-heptane, carbon tetrachloride, and benzene and poly(vinyl methyl ether) between 120 and 180°C (1990)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 28 (1990), S. 2411-2420 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The corresponding-states theory of Flory has been used to characterize the interaction between three different probes, n-heptane, carbon tetrachloride, and benzene, with poly(vinyl methyl ether). Different results are obtained if the characteristic parameters are corrected for their temperature dependences, which are compared for the three different probes. It turns out that the variation with temperature of the interaction energy parameter X12 is also different when using temperature-dependent or temperature-independent reduction parameters. The interaction is weak and very sensitive to small deviations from ideality in the corresponding-states theory. These results suggest that a weakening of polymer-polymer interactions, and not free volume differences, is responsible for the phase separation in polystyrene/poly(vinyl methyl ether) blends.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1990.090281217
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  • 7
    Electronic Resource
    Electronic Resource
    Thermodynamics of miscible polymer blends using a concentration-dependent χ parameter (1988)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 26 (1988), S. 1769-1780 
    Details
    ISSN: 0887-6266
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Flory equation-of-state theory, as expressed by Patterson and co-workers, has been applied to two miscible polymer blends: poly(vinyl chloride)/poly(ε-caprolactone) and poly(methyl methacrylate)/poly(vinylidene chloride). For both blends, the variation of the polymer-polymer interaction parameter, χ′23, as a function of composition, is mostly small and can be accounted for by the Flory theory. However, for poly(vinyl chloride)/poly(ε-caprolactone) blends, at high poly(ε-caprolactone content), the large variation of χ′23 as a function of concentration can be explained by a variation of the surface-to-volume ratio of the polymers in the mixture with blend composition. The variations of the surface-to-volume ratios determined in this study agree with those reported in the literature using small-angle x-ray scattering.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1988.090260816
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  • 8
    Electronic Resource
    Electronic Resource
    Molecular size and solvation of low molecular weight poly(ethylene oxide) and phenol-formaldehyde resols in different solvents (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 39 (1990), S. 341-353 
    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 solvent systems are presently used to characterize the molecular weight of phenol-for-maldehyde resins. However, results reported in the literature for different molecular weights may not be representative of true molecular weight, but rather may be distorted by aggregation and solvation. In this report an effort to clarify this situation was conducted, first by using a suitable calibration with poly(ethylene glycol) and then using this polymer as a molecular size standard to determine the size of phenol-formaldehyde oligomers in solution. In the calculation of the molecular sizes of phenol-formaldehyde resols, proper accounting of the variation of the Mark-Houwink parameters with molecular weight for low degrees of polymerization must be made for poly(ethylene glycol). The Mark-Houwink constants for poly(ethylene glycol) are very similar in presence or absence of salts, and are considered to be unaffected by solution ionic strength. It is not the case for phenol-formaldehyde, whose apparent molecular size varies with the nature of the solvent. The actual molecular weight and molecular dimension distribution are discussed for different type A resols used as adhesives in the wood composite industry.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070390211
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  • 9
    Electronic Resource
    Electronic Resource
    Surface analysis of press dried-CTMP paper samples by electron spectroscopy for chemical analysis (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 61 (1996), S. 545-552 
    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 effect of press-drying temperature on the surface chemistry of chimicothernomechanical pulp fibers has been studied using electron spectroscopy for chemical analysis (ESCA). The chemical composition showed no significant variation for press-dried samples at temperatures between 25 and 140°C. On the other hand, ESCA showed that lignin content increased whereas hemicelluloses content decreased on the surface of press-dried samples at 175°C. By its hydrophobic nature, lignin gives to paper and paperboards better dimensional stability and resistance to moisture and water. However, lignin does not intervene in fiber bonding because the specific bond strength does not vary with press-drying temperature. © 1996 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Changes in molecular weight and molecular size with reaction time of a phenol-formaldehyde resol (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 3271-3273 
    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
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1991.070421221
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