Preparation of branched polystyrene via atom transfer radical polymerisation using diene with electron-rich double bond

Self-designed bis(4-vinylbenzyl)-oxalate (DBE) was synthesized successfully. The branched polystyrene was prepared by using an atom transfer radical polymerization method with copper bromide (CuBr)/2,2'-bipyridine (Bpy) as a catalyst, the DBE as a branched monomer and tert-butyl α-bromoisobutyrate (t-BBiB) as an initiator. The structure of the synthesized branched monomer was determined by nuclear magnetic resonance (NMR) spectroscopy. The conversion of monomer during the polymerization was measured by gas chromatography (GC) while the molecular weight, molecular weight distribution and degree of branching of the polystyrene were characterized by three-detection volume exclusion chromatography (TD-SEC). The results show that bis(4-vinylbenzyl)-oxalate with electron-rich double bond and styrene with electron-rich double bond can be successfully obtained branched polystyrene. The branched structure developed as the reaction proceeded. At the same time, the molecular weight of the branched polystyrene gradually increased as the reaction progressed, and the molecular weight distribution widened consistent with the increased degree of branching.