Continuous spin fractionation and characterization by size-exclusion chromatography for styrene-butadiene block copolymers |
| |
Authors: | Xiong Xiaopeng Eckelt John Wolf Bernhard A Zhang Zhengjun Zhang Lina |
| |
Institution: | Department of Chemistry, Wuhan University, 430072 Wuhan, China. |
| |
Abstract: | Linear and star-shaped styrene-butadiene block copolymers synthesized by anionic polymerization of butadiene and styrene were fractionated by applying a newly developed large-scale fractionation technique, named continuous spin fractionation (CSF). Their molecular weight and polydispersity index (d=M(w)/M(n)) were measured with size-exclusion chromatography and static light scattering. For the linear triblock copolymer a fractionation via temperature variation turned out to be better suited than the usual isothermal procedure. The star-shaped polymer with the d value of 1.33 was fractionated in two CSF steps to get the targeted sample, which has a considerably more uniform structure and a narrower molecular weight distribution (d=1.11). The corresponding starting linear diblock copolymer was fractionated in one step reducing d from 1.68 to 1.17. With one set of simple laboratory equipment, 1kg polymer can be fractionated per day. Utilizing CSF, for the first time, we fractionated successfully the block copolymers. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|