Synthesis and Properties of SEPS-g-PEO Copolymers with Varying Branch Lengths  

作　　者：Zhong-Fu Zhao Pei-Ying Liu Chun-Qing Zhang Wei Liu Yan-Hui Wang Tao Tang Yi-Fu Ding Yan-Dong Zhang Fan-Zhi Meng 

机构地区：[1]State Key Laboratory of Fine Chemicals,School of Chemical Engineering,Dalian University of Technology [2]State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences [3]Department of Mechanical Engineering,University of Colorado Boulder

出　　处：《Chinese Journal of Polymer Science》2018年第8期934-942,共9页高分子科学（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Nos.51673034 and 51233005);the Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry (Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,No.110000R088)

摘　　要：Poly（ethylene oxide） （PEO） was controllably grafted from styrene-b-（ethylene-co-propylene）-b-styrene （SEPS） backbones by combining lithiation of styrenic units and living monomer-activated anionic ring-opening polymerization of ethylene oxide （EO） monomers with the aid of co-initiators triisobutyl aluminum. The as-synthesized SEPS-g-PEO copolymers were characterized by SEC, 1H-NMR, FTIR, SAXS, AFM and DSC. When the branch length is relatively small, increase of PEO fraction leads to the increase of the correlation length between neighboring hard domains, but the degree of correlation reduces. When the branch length is relatively large, the phase-separated structures become random both in terms of size and spatial correlation, and macro-phase separated structures appear. The crystallization behavior of the PEO branches can be effectively inhibited in SEPS-g-PEO, so no significant crystallization takes place until the fraction of PEO branches is 20.1 wt%, which greatly promotes the rapid delivery of hydrophilic drugs in the hot-melting pressure- sensitive adhesives （HMPSAs） based on SEPS-g-PEO. Their cumulative release amount of a model drug could achieve 80%, more than twice the value in the HMPSAs based on linear PEO-containing styrenic block copolymers.Poly（ethylene oxide） （PEO） was controllably grafted from styrene-b-（ethylene-co-propylene）-b-styrene （SEPS） backbones by combining lithiation of styrenic units and living monomer-activated anionic ring-opening polymerization of ethylene oxide （EO） monomers with the aid of co-initiators triisobutyl aluminum. The as-synthesized SEPS-g-PEO copolymers were characterized by SEC, 1H-NMR, FTIR, SAXS, AFM and DSC. When the branch length is relatively small, increase of PEO fraction leads to the increase of the correlation length between neighboring hard domains, but the degree of correlation reduces. When the branch length is relatively large, the phase-separated structures become random both in terms of size and spatial correlation, and macro-phase separated structures appear. The crystallization behavior of the PEO branches can be effectively inhibited in SEPS-g-PEO, so no significant crystallization takes place until the fraction of PEO branches is 20.1 wt%, which greatly promotes the rapid delivery of hydrophilic drugs in the hot-melting pressure- sensitive adhesives （HMPSAs） based on SEPS-g-PEO. Their cumulative release amount of a model drug could achieve 80%, more than twice the value in the HMPSAs based on linear PEO-containing styrenic block copolymers.

关 键 词：Living anionic polymerization SEPS-g-PEO copolymers Phase structures Drug delivery 

分 类 号：O631[理学—高分子化学] TQ460.1[理学—化学]