Branched polystyrenes from suspension “Strathclyde” polymerization using a vulcanization accelerator as a chain transfer agent†
Branched polymers exhibit a unique three-dimensional (3D) molecular architecture and distinctive physical/chemical properties, and thus have been applied in a wide variety of fields. Aqueous suspension polymerization provides a cost-effective method for polymer synthesis not only because water is an excellent heat-transfer medium, but also because it circumvents the complicated and time-consuming polymer purification process. Herein, using tetramethylthiuram disulfide (TMDS), a common rubber vulcanization accelerator, as a chain transfer agent (CTA), a series of branched polystyrenes (BPS) were synthesized by suspension polymerization through the “Strathclyde” approach with ethylene glycol dimethacrylate (EGDMA), ethylene glycol diacetate (EGDA), and divinylbenzene (DVB) as branching units, respectively. Melt rheology and differential scanning calorimetry (DSC) characterization further show that the BPS have a low melt viscosity and better chain segment mobility, making them appealing rheological modifier candidates.