ADSORPTION BEHAVIOR OF END-FUNCTIONALIZED POLYMERS MODIFIED BY IMINIUM ION

In order to clarify the end-functionalization effect of polymers modif ied by iminium ion, a model compound with a modified chain end was pre pared by directly reacting n-butyllithium with N-methyl-2-pyrrolidone and then quenching by the addition of methanol. It is shown that the m odel compound includes the iminium ion group and that the adsorption b ands in the IR-spectra of the chemically modified polymer were similar to those of model compound. The adsorption behavior of end-functional ized polystyrene(PS-X) and diblock copolymer of PS and polybutadiene(P B) which were modified by iminium ion(PS-PB-X), were examined over a w ide range of molecular weights of these polymers. It is evident that t he amount of adsorption increased significantly by the end-functionali zation and this trend was especially strong in the low molecular weigh t polymers (M(W) less than or equal to 10(5)). The preference for the end-functionalized polymer was also examined by competitive and sequen tial adsorption experiments between different molecular weight species . It is shown that a prefered adsorption of PS-X with low molecular ma ss is pronounced over the adsorption of PS or PS-X with high molecular weight and in the combination of high and low molecular weight specie s of PS-X, a special enhancement of total adsorption can be observed. This enhancement is based on a combination of different adsorption lay ers formed by these two molecular weight species.