Original route to polylactide-polystyrene diblock copolymers containing a sulfonyl group at the junction between both blocks as precursors to functional nanoporous materials
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- 作者：Rim Majdoub ; Tarek Antoun ; Benjamin Le Droumaguet ; Mourad Benzina ; Daniel Gr ; e
- 关键词：Semi-hydrolyzable diblock copolymers ; Sulfonyl-functionalized junction point ; Ring-opening polymerization/atom transfer radical polymerization tandem approach ; Selective hydrolysis ; Functional nanoporous materials
- 刊名：Reactive and Functional Polymers
- 出版年：2012
- 出版时间：August, 2012
- 年：2012
- 卷：72
- 期：8
- 页码：495-502
- 全文大小：757 K
文摘
Novel functionalized nanoporous polymeric materials could be derived from poly(D,L-lactide)-block-polystyrene (PLA-b-PS) diblock copolymers with a sulfonyl group at the junction between both blocks were synthesized by a combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) using a synthetic difunctional initiator through a three-step sequential methodology. Different ¦Ø-bromo PLA polymers with various molar masses ranging from 3640 to 11,440 g mol?1 were first produced by coupling ¦Ø-hydroxy PLA precursors to a chlorosulfonyl-functionalized ATRP initiator previously prepared, thus leading to the formation of suitable macroinitiators for the subsequent ATRP polymerization of styrene. Consequently, PLA-b-PS diblock copolymers were obtained with a finely tuned PLA volume fraction (fPLA) in order to develop a microphased-separation morphology. The resulting copolymers as well as the intermediate compounds were carefully analyzed by size exclusion chromatography and 1H NMR. Upon shear flow induced by a channel die processing, oriented copolymers were generally afforded as characterized by small-angle-X-ray scattering (SAXS). Such copolymers were finally submitted to mild alkaline conditions so as to hydrolyze the sacrificial PLA block, and the presence of the sulfonic acid functionality on the pore walls of the resulting nanoporous materials was evidenced by means of a post-modification reaction consisting in the corresponding sulfonamide formation.