By means of a closely intermeshing twin-screw extruder as the reactor

the mixture of styrene (S) and butadiene (B) as the monomer and THF as the polar catalyst

a copolymer (S/B) was synthesized by bulk polymerization with the organic lithium initiator.The PB chain of copolymers was cleaved by reaction with hydrogen peroxide in the presence of osmium tetraoxide

then the small molecules were removed out of the system by purification.The copolymers and the segments after oxidization were characterized by GPC cooperating with a multi-angle laser light scattering instrument (MALLS).It was found that the molecular weight distributions of the S/B copolymers were broadened

on the other hand

the molecular weights of the segments after oxidization decreased by addition of THF.The content of 1

2-PB was derived from 1H-NMR.It was confirmed that the content of 1

2-PB increased obviously as THF was stepped up

but to a great extent the trend of increasing was slow down.Cooperated with the survey of TEM photographs

it was confirmed that the phase of polybutadiene was minished by THF

and its distribution was more uniform.So it could be concluded that the basic mechanism of anionic polymerization during reactive extrusion was consistent with that in anionic solution polymerization

the difference only resulted from process factors during the reactive extrusion.