Abstract: A polymer comprising at least one polymer chain is produced by polymerizing, in the presence of a radical generating source and an iodide compound, at least one monomer M.sub.1 having a radically polymerizable unsaturated bond between a carbon atom and an iodine atom constituting a carbon-iodine bond of the iodide compound to form at least one polymer chain between the carbon atom and the iodine atom, wherein the polymerization reaction is carried out in the presence of a monomer M.sub.2 which is different from the monomer M.sub.1 and has a larger addition reactivity with a carbon radical which is generated by cleavage of the carbon-iodine bond of the iodine compound than that of the monomer M.sub.1.

Abstract: An iodine-containing compound consisting of at least two repeating units selected from the formulae:--(CH.sub.2 CF.sub.2 CF.sub.2 O).sub.a ----(CHClCF.sub.2 CF.sub.2 O).sub.b ----(CCl.sub.2 CF.sub.2 CF.sub.2 O).sub.c ----(CHFCF.sub.2 CF.sub.2 O).sub.d ----(CFClCF.sub.2 CF.sub.2 O).sub.e ----(CF.sub.2 CF.sub.2 CF.sub.2 O).sub.f --wherein a, b, c, d, e and f are each 0 or a positive integer and satisfy the following equations:2.ltoreq.a+b+c+d+e+f.ltoreq.200 and1.ltoreq.a+c+d+fand an iodine atom at at least one end of a molecule, which can provide a block copolymer which is useful as a grease.

Abstract: A fluorovinyl ether of the formula:XCH.sub.2 CF.sub.2 CF.sub.2 --(OCH.sub.2 CF.sub.2 CF.sub.2).sub.m --(OCFYCF.sub.2).sub.n --OCF.dbd.CF.sub.2 (I)wherein X is a hydrogen atom or a halogen atom (e.g. fluorine, chlorine, bromine and iodine); Y is a fluorine atom or a trifluoromethyl group; m is an integer of 0 to 5; and n is 0, 1 or 2, which can modify a polymer of at least one ethylenically unsaturated compound.

Abstract: An iodine-containing compound consisting of at least two repeating units selected from the formulae:--(CH.sub.2 CF.sub.2 CF.sub.2 O).sub.a ----(CHClCF.sub.2 CF.sub.2 O).sub.b ----(CCl.sub.2 CF.sub.2 CF.sub.2 O).sub.c ----(CHFCF.sub.2 CF.sub.2 O).sub.d ----(CFClCF.sub.2 CF.sub.2 O).sub.e ----(CF.sub.2 CF.sub.2 CF.sub.2 O).sub.f --wherein a, b, c, d, e and f are each 0 or a positive integer and satisfy the following equations:2.ltoreq.a+b+c+d+e+f.ltoreq.200 and1.ltoreq.a+c+d+fand an iodine atom at at least one end of a molecule, which can provide a block copolymer which is useful as a grease.

Abstract: An iodine-containing compound consisting of at least two repeating units selected from the formulae:--(CH.sub.2 CF.sub.2 CF.sub.2 O).sub.a ----(CHClCF.sub.2 CF.sub.2 O).sub.b ----(CCl.sub.2 CF.sub.2 CF.sub.2 O).sub.c ----(CHFCF.sub.2 CF.sub.2 O).sub.d ----(CFClCF.sub.2 CF.sub.2 O).sub.e ----(CF.sub.2 CF.sub.2 CF.sub.2 O).sub.f --wherein a, b, c, d, e and f are each 0 or a positive integer and satisfy the following equations:2.ltoreq.a+b+c+d+e+f.ltoreq.200 and1.ltoreq.a+c+d+fand an iodine atom at at least one end of a molecule, which can provide a block copolymer which is useful as a grease.