Polymer Swelling. 18. Sorption of Geminal and Terminal Polyalkoxy-Substituted Alkanes by Poly(styrene-co-divinylbenzene)

The adsorption parameters (α) of polyalkoxy alkanes CH4-z Z z , CH3-z Z z (CH2) n H, and Z(CH2) n CH3-z Z z , in which Z is either CH3O or CH3CH2O, were established experimentally in the usual way. − In the cases of those homologous series that comprise the structural classifications CH3-z Z z (CH2) n H or Z(CH2) n CH3-z Z z , the α n -values for only two or three of the lower members (n < 5) in a given series were determined experimentally; the rest were established by extrapolation or interpolation using the appropriate log α n vs n linear relationship, as described in the text. The results obtained thereby support the conclusions derived earlier from similar studies6 in which Z was either a chloro or a bromo substituent, namely, that liaison between the adsorbed molecule and the polymer at liquid-saturation is monodentate rather than polydentate. The other Z-substituents on the carbon atoms adjacent to the adsorption site affect α in a manner that reflects not only the net influence of electronic and steric contributions at this site but also the affinity of these substituents for the mobile sorbed-but-not-adsorbed molecules in the liquid-saturated system. Hence, systematic incrementation of these Z-substituents to the allowable limit at constant n does not afford a linear log α z vs z relationship but rather reflects one that exhibits a maximum at z = 2 or 3, depending upon the series. On the other hand, similar systematic incrementations of Z on carbon atoms further removed from the adsorption site do exhibit log α z vs z linear relationships at constant n in the manner previously noted for log α n vs n relationships at constant z.