Molecular design, synthesis and characterization of star-branched styrene-butadiene-styrene copolymer

Abstract

A series of polystyrene macromonomers were synthesized by living anionic polymerization technique using styrene as monomer and p-vinylbenzyl chloride as capping agent.The star-branched styrene-butadiene-styrene (S-g-SBS) copolymer with ordered polystyrene as side chains was designed and synthesized using butadiene and polystyrene macromonomer as monomers and divinyl benzene as coupling agent.The chemical constitution and microstructure of polystyrene macromonomers and S-g-SBS were characterized by proton nuclear magnetic resonance spectrometer, gel permeation chromatographer and differential scanning calorimeter, and the rheological properties of S-g-SBS were analyzed by rotational rheometer.The results showed that polystyrene macromonomers with controlled molecular weight and narrow molecular weight distribution were obtained.The content of 1,2-structure of polybutadiene in S-g-SBS could be regulated between 30% and 70%, and the lower the content of 1,2-structure, the lower the melt viscosity.For the similar molecular structural parameter, the melt viscosity of S-g-SBS was obviously lower than that of linear SBS.

Keywords

• living anionic polymerization
• polystyrene macromonomer
• star-branched structure
• styrene-butadiene-styrene copolymer
• rheological property
• melt viscosity