ISSN:
0959-8103
Keywords:
solution viscosity
;
Mark-Houwink-Sakurada equation parameter
;
acetylated o-cresol-formaldehyde resin
;
unperturbed dimension
;
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:
o-Cresol-formaldehyde resin (OC) and five kinds of acetylated OC (AC-X-OC; X is the degree of acetylation) were prepared. The Θ-temperature for each resin was determined by means of the Shultz-Flory method, and their molecular conformations in both tetrahydrofuran (THF) and Θ-solvent were estimated from the values of the exponents in the Mark-Houwink-Sakurada equations. The effect of the degree of acetylation on the exponent was negligible in THF, but was remarkable in Θ-solvent. In THF, the molecular chains of these resins are relatively extended, because the hydrogen bond between phenolic hydroxyl groups is loosely formed. In Θ-solvent, however, the molecular conformation is compact and the resins are considered to form a pseudo cross-linked network structure through inter- and/or intra-molecular hydrogen bonds. The Mark-Houwink-Sakurada equation for AC-100-OC in 2-ethoxyethanol at 92.0°C was found to be [η]θ = 0.0773 M̄0.50n, where [η]0 is the limiting viscosity number under the Θ-condition, and M̄n is the number-average molecular weight. The unperturbed dimension, (〈r20〉/M̄n)1/2, 〈r20〉 being the unperturbed mean square end-to-end distance, for AC-100-OC was found to be 0.659×10-8 cm g-1/2 mol1/2.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pi.1995.210360405
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