STUDIES ON MICROGELS .1. MICROGEL FORMATION STUDIED BY GEL-PERMEATION CHROMATOGRAPHY WITH AN ONLINE LIGHT-SCATTERING DETECTOR

The previously described microgel synthesis in which living poly(4-tert-butylstyrene) was reacted with 1,4-divinylbenzene was studied. Samples were taken after the addition of the crosslinker and characterized by gel-permeation chromatography (GPC) with an on-line multi angle laser light scattering (MALLS)- and a differential refractive index (DRI) detector. Primary particle formation was found early in the reaction followed by interparticular crosslinking. The GPC calibration curves allowed the derivation of a branching plot. The branching plots showed, that in addition to interparticular crosslink reactions also intraparticular crosslink reactions are occurring. The plots also showed that the primary particles scale like linear polymers, which led to the conclusion that they consist of comb-like structures with poly(4-vinylstyrene) as the backbone and poly(4-tert-butylstyrene) as branches.