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:
Phenolic and amino resins on the basis of α,β-unsaturated aldehydes were synthesized in bulk or solution. Catalysts were HCl, H3PO4, or formic acid, and in some cases NaOH. The course of the reactions was followed by GPC and NMR while the structure of the reaction products was determined by one- and two-dimensional NMR. The course of the reactions is influenced by experimental conditions: the type of monomers, their molar ratio, the type and quantity of the catalyst, the reaction time and temperature, and the reaction medium. At the beginning of the reaction the addition of a nucleophile to an aldehyde takes place through parallel 1,2-addition to and 1,4-addition to group. Oligomers with —OH, , and —CHO functional groups are able to add new monomer units or to react mutually to form higher molecular weight addition and condensation products. The overall rate constants for the beginning of the reactions were between 10-3 L/mol s for the high reactive mixtures and 10-7 L/mol s for the less reactive mixtures. The resins were cured by heating at temperatures above 135°C with the addition of hexamethylenetetramine.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1992.070450406
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