ISSN:
0022-3832
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
When a crosslinking agent is added to a very dilute solution of a linear high polymer, there will be practically exclusively a self linking of the individual statistical coils, i.e., the molecules of the crosslinking agent will link different parts of the same macromolecule, transforming the original linear high polymer into a three-dimensional network, practically without a change of its molecular weight. The process of self-linking of a single coil is associated with a contraction of its average external dimensions and therefore with a decrease of the intrinsic viscosity. If the crosslinking produced by the action of v molecules of the crosslinking agent on one linear polymer molecules occurs statistically and if the original linear high polymer molecule is made of Nm statistical chain elements, a decrease of the intrinsic viscosity should occur from the value [η]open to [η]v crosslinks, statist, where \documentclass{article}\pagestyle{empty}\begin{document}$ [\eta ]_{\nu {\rm crosslinks, statist}} = [\eta ]_{{\rm open}} [1 - \nu (\sqrt 2 /\sqrt {N_m } )] $\end{document}. In order to test the validity of this formula a dilute, slightly acid solution of polyvinyl alcohol with M = 100,000 was crosslinked by means of terephthalaldehyde [CHO—C6H4—CHO]. The agreement of the values of [η] observed in very dilute solution with the theoretical value indicates the actual statistical formation of cycles through the reaction of terephthalaldehyde on dissolved solitary linear polyvinyl alcohol molecules.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pol.1962.1205716524
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