Initiation system and process for anionic (co)polymerization of (meth)acrylic, vinylaromatic and/or diene monomers
AssigneeAtofina
InventorsTHOMAS ZUNDEL, PHILIPPE TEYSSIE, ROBERT JEROME, CHRISTOPHE NAVARRO
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Abstract
The present invention relates to an initiation system composed of the reaction product of at least one cyclic siloxane and at least one organometalic compound of sufficient reactivity to open the siloxane ring. Application of the present invention is to the preparation of homopolymers of (meth)acrylic, vinylaromatic or diene monomers, random or block copolymers of these monomers and, in particular, application to poly(methylmethacrylate) with a high content of isotactic triads.
Claims18
An initiation system for anionic (co)polymerization of (meth)acrylic, vinylaromatic and/or diene monomers, comprising the reaction product
- a) of at least one cyclic siloxane of Formula I:
- 8
- wherein:
- R and R′, identical or different, each represent a C1-C6 linear or branched alkyl radical, or an aryl radical, an arylalkyl or an alkylaryl radical, wherein the alkyl group has from 1 to 6 carbon atoms and
- p is a whole number from 3 to 6, representing the number of siloxane units,
- b) of at least one organometalic compound with sufficient reactivity to open the siloxane ring,
- the molar ratio r=no/n, wherein no is the number of moles of active sites deriving from the organometalic compound reacting with n moles of cyclic siloxane compound, being between 0.8p and 2p, wherein p represents the number of siloxane units.
A process for preparing an initiation system comprising the reaction product
- a) of at least one cyclic siloxane of Formula I:
- 12
- wherein:
- R and R′, identical or different, each represent a C1-C6 linear or branched alkyl radical, or an aryl radical, an arylalkyl or an alkylaryl radical, wherein the alkyl group has from 1 to 6 carbon atoms and
- p is a whole number from 3 to 6, representing the number of siloxane units,
- b) of at least one organometalic compound with sufficient reactivity to open the siloxane ring, the molar ratio r=no/n, wherein no is the number of moles of active sites deriving from the organometalic compound reacting with n moles of cyclic siloxane compound, being between 0.8p and 2p, wherein p represents the number of siloxane units,
- said process characterized in that n moles of cyclic siloxane and no moles of active sites deriving from the organometalic compound are reacted at ambient temperature for sufficient time to achieve an equilibrium favorable to the thermodynamically stable species, the no/n ratio being between 0.8p and 2p, where p is a whole number from 3 to 6 representing the number of siloxane units.
Dependencies are inferred from the claim text.