An ethylenically unsaturated polymer includes at a terminus the radical of an allylic compound that includes a functional group free of active hydrogen atoms that is bonded to the allylic C atom through a S, P, Si or Sn atom and a vinyl aromatic compound. The polymer can be used as a component of a variety of elastomeric compounds used in the production of vulcanizates.

The invention relates to a method of polymerizing at least one monomer comprising a vinylidene fluoride monomer, the method comprising putting in contact the at least one monomer with a polymerization initiator -and an oxidizing agent, the polymerization initiator having the formula (I):

##STR00001##

wherein R.sub.f is a fluoroalkyl group comprising from 1 to 3 carbon atoms; and M.sup.x+ is chosen from a monovalent cation, or a divalent cation, or a trivalent cation, or a tetravalent cation.

Provided is an ethylene-vinyl alcohol copolymer with an ethylene unit content of 15 to 60 mol % and a saponification degree of 85 mol % or more.

An ethylenically unsaturated polymer includes at a terminus the radical of an allylic compound that includes a functional group free of active hydrogen atoms that is bonded to the allylic C atom through a S, P, Si or Sn atom and a vinyl aromatic compound. The polymer can be used as a component of a variety of elastomeric compounds used in the production of vulcanizates.

An ethylenically unsaturated polymer includes at a terminus the radical of an allylic compound that includes a functional group free of active hydrogen atoms that is bonded to the allylic C atom through a S, P, Si or Sn atom and a vinyl aromatic compound. The polymer can be used as a component of a variety of elastomeric compounds used in the production of vulcanizates.

An ethylenically unsaturated polymer includes at a terminus the radical of an allylic compound that includes a functional group free of active hydrogen atoms that is bonded to the allylic C atom through a S, P, Si or Sn atom and a vinyl aromatic compound. The polymer can be used as a component of a variety of elastomeric compounds used in the production of vulcanizates.

Provided is an ethylene-vinyl alcohol copolymer with an ethylene unit content of 15 to 60 mol % and a saponification degree of 85 mol % or more.

A method for producing a polymer containing metal atoms or halogen atoms at the terminals thereof with excellent efficiency while minimizing or eliminating side reactions or the like is provided. The method can also freely control molecular weight characteristics of the polymer.

The invention relates to a method of polymerizing at least one monomer comprising a vinylidene fluoride monomer, the method comprising putting in contact the at least one monomer with a polymerization initiator and an oxidizing agent, the polymerization initiator having the formula (I):
(R.sub.fSO.sub.2.sup.).sub.xM.sup.x+(II)
wherein R.sub.f is a fluoroalkyl group comprising from 1 to 3 carbon atoms; and M.sup.x+ is chosen from a monovalent cation, or a divalent cation, or a trivalent cation, or a tetravalent cation.