STRUCTURAL FACTORS IN POLYMERIZATION 



4S 



with alkali, its activity as a matrix increased strikingly, with as much as 50 milli- 

 grams of lignin now being deposited per gram. 



Following these preliminary studies ot matrix activity, a number ol sub- 

 stances was surveyed for suitability and yield (table 2). Of the substances listed, 

 only the high molecular weight polysaccharides direct the formation ol lignin. 

 It was of interest to hnd activity at a high level to be associated most with the 

 less ordered, more dispersible polysaccharides such as starch and mcthylcelluloses. 

 Most attention was given to the methylcelluloses, which were effective in con- 

 centrations of 10 ' to io~"m; concentrations on the order of 10 'm and above, 

 on the other hand, were inhibitory to peroxidation of eugenol. Methylcellulose 

 lignin, like cellulose lignin, was separable into dioxane- and ethanol-HCl-soluble 

 fractions. The dioxane-soluble fraction yielded, on analysis, C, 62.7 ''/f ; H, 6.9%; 

 OCH.;, 15.9 '/f ; the fraction extractable on ethanolysis yielded C, 63.8%; H, 6.4%; 

 OCH;;, 15.4'/* . The latter, again in a state of depolymerization, yielded for 

 molecular weight a value of 763 ±79, corresponding to a degree of polymeriza- 

 tion of 3 to 5. 



When the products obtained with various matrices were compared as to solu- 

 bility classes and ultraviolet spectra, differences observed suggested the existence 

 of a certain degree of specificity. Recognizing three general spectral types (fig. 3), 

 the matrices tested (tables 3 and 4) show considerable variation with respect to 

 detail of absorption and further distinctions attributable to differences between 

 water-soluble and insoluble polysaccharides. Such spectral distinctions are prob- 

 ably based principally upon degree of polymerization, heterogeneity of product, 

 and, to a lesser extent, upon isomerism. 



It was anticipated when matrix studies were first begun that cellulose would 

 be the most suitable matrix, and indeed, it was assumed that the correctness of 

 this view would constitute a test of the biological validity of a matrix system. 

 After study of the far superior methyl-cellulose matrix it seemed possible that 

 part of its greater efficacy might be associated with its dispersion in aqueous media. 

 Of the soluble polysaccharides that would be widespread in young cells and 



Table 2. Matrix activity oi- various substances in lignin formation 



