although the separation criterion in the columns is the hydrodynamic volume of the molecules. Experimental results are found to be consistent with a scaling description of the sol-gel transition.
The degradation of poly(phenylacetylene), a typical autoxidatively degradable polymer of substituted acetylene, is shown to take place inside the SEC (size exclusion chromatography) columns during the polymer analysis carried out with eluent (THF) not protected from air. Three types of experimental evidence are given based on the comparison of results of SEC analyses carried out: (i) with the eluent kept under air or argon atmosphere; (ii) with different flow rates of the eluent; and (iii) with and without the interruption of the analysis for a few hours. Other degradable polymers of substituted acetylene are mentioned and recommendations for their SEC analyses are given.
Phenylacetylene was polymerized with WOCl,/tetraphenyltin (mole ratio 1 : 2) catalyst in benzene and benzene/ 1 ,4-dioxane mixtures. The resulting polymers were characterized by means of multidetector size-exclusion chromatography and ' H NMR and IR spectroscopy. 1,4-Dioxane used as a co-solvent was found to increase both the content of cis units and the molecular weight of poly(pheny1acetylene) (PPhA); a weight-average molecular weight of a, = 1 . lo6 was reached. In spite of the high mole ratio monomer: catalyst (1 260: 1) used in the polymerizations high yields of PPhA were attained. No effect of an alteration in PPhA microstructure upon its degradation in tetrahydrofuran solution exposed to air has been observed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.