Synthesis of macrocyclic polymers having low hysteresis compounded properties
AssigneeBridgestone Corporation
InventorJames E. Hall
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Abstract
The present invention provides a method of anionic synthesis of stable macrocyclic polymers that are compounded to form vulcanizable elastomeric compounds exhibiting reduced hysteresis properties. Cyclic organometallic compounds containing divalent metal atoms of Groups IIA and IIB of the Periodic System are employed as initiators of anionic polymerization of conjugated diene, vinyl aromatic and/or triene monomers. Coupling of the living ends of the resulting macrocyclic polymers or copolymers with a coupling agent or a coupling agent that is also a functionalizing agent results in stable macrocyclic polymers with improved hysteresis properties.
Claims19
A method for preparing a vulcanizable elastomeric compound having reduced hysteresis properties, comprising the steps of:
- forming a solution of one or more unsaturated anionically polymerizable monomers in a solvent;
- polymerizing the monomer in the presence of an initiator comprising a cyclic organometallic compound that comprises a divalent metal atom (Mt) and a reactant (Rct) contained in a ring, having the formula ##STR7## where m and n each independently represent at least one;
- terminating the polymerization reaction with a coupling agent;
- and
- adding from about 5 to about 80 parts by weight of a filler selected from the group consisting of silica, carbon black, and mixtures thereof, to form a vulcanizable elastomeric compound.
A method of preparing a functionalized macrocyclic polymer having improved hysteresis properties, the polymer formed by the polymerization of at least one unsaturated anionically polymerizable monomer in the presence of an anionic polymerization initiator comprising a cyclic organometallic compound that comprises a divalent metal atom (Mt) and a reactant (Rct) contained in a ring, having the formula ##STR8## where m and n each individually represent at least one, the improvement comprising terminating the polymerization with a functionalizing agent.
Dependencies are inferred from the claim text.