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Synthesis of polydimethylsiloxane‐ block ‐polystyrene‐ block ‐polydimethylsiloxane via polysiloxane‐based macroinitiator in supercritical CO 2
Author(s) -
Akgün Mesut,
Deniz Sennur,
Baran Nil,
Uzun Nimet I,
Akgün Nalan A,
Dinçer Salih
Publication year - 2005
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.1695
Subject(s) - polydimethylsiloxane , materials science , copolymer , polystyrene , polymer chemistry , styrene , supercritical fluid , polymerization , gel permeation chromatography , radical polymerization , thermogravimetric analysis , chemical engineering , polymer , chemistry , organic chemistry , composite material , engineering
Abstract Polydimethylsiloxane‐ block ‐polystyrene‐ block ‐polydimethylsiloxane (PDMS‐ b ‐PS‐ b ‐PDMS) was synthesized by the radical polymerization of styrene using a polydimethylsiloxane‐based macroazoinitiator (PDMS MAI) in supercritical CO 2 . PDMS MAI was synthesized by reacting hydroxy‐terminated PDMS and 4,4′‐azobis(4‐cyanopentanoyl chloride) (ACPC) having a thermodegradable azo‐linkage at room temperature. The polymerization of styrene initiated by PDMS MAI was investigated in a batch system using supercritical CO 2 as the reaction medium. PDMS MAI was found to behave as a polyazoinitiator for radical block copolymerization of styrene, but not as a surfactant. The response surface methodology was used to design the experiments. The parameters used were pressure, temperature, PDMS MAI concentration and reaction time. These parameters were investigated at three levels (−1, 0 and 1). The dependent variable was taken as the polymerization yield of styrene. PDMS MAI and PDMS‐ b ‐PS‐ b ‐PDMS copolymers obtained were characterized by proton nuclear magnetic resonance and infrared spectroscopy. The number‐ and weight‐average molecular weights of block copolymers were determined by gel permeation chromatography. Copyright © 2004 Society of Chemical Industry