info:eu-repo/semantics/conferenceProceedings
TOWARDS THE SINTHESIS OF BLOCK COPOLYMERS USING OXOAMMONIO SALTS
Autor
JOSE BONILLA CRUZ
TANIA ERNESTINA LARA CENICEROS
ENRIQUE SALDIVAR GUERRA
Institución
Resumen
Great interest has been focused on end-functional polymers as prepolymer
for the synthesis of block and graft copolymers, polymer networks, and chain-extended
polymers1. Particularly, few works2 have explored the synthesis of block copolymers of
polydimethylsiloxane-block-polystyrene (PDMS-b-PSt), or polyethylenglycol-blockpolystyrene
(PEG-b-PSt) using prepolymer of PDMS or PEG as a macroinitiator in the
presence of nitroxide radicals and styrene monomer (St). On the other hand, considerable
efforts have been committed for the synthesis of this kind of block copolymers: i) some
approaches involve first the chemical modification of PDMS3 or PEG4 with azo-initiator
moieties obtaining thus a macroinitiator, in order to form PDMS-b-PSt or PEG-b-PSt in the
presence of MTEMPO (4-methoxy-2,2,6,6,tetramethylpiperidine-1-oxyl) and St; ii) anionic
ring-opening polymerization in combination with nitroxide chemistry have been used in the
synthesis of hexamethylciclotrisiloxane-styrene diblocks5; iii) The modification of a PDMS
(previously synthesized by anionic polymerization) with a difunctional allyl ether6,
derivative of a difunctional initiator developed by Hawker7. These macroalkoxyamines in
the presence of St leads to PDMS-b-PSt, in which the growth to the PSt block was
controlled by nitroxide radicals. All these efforts involve both ingenious structures and
numerous synthesis pathways.
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