Provided is an optical article having a substrate, a primer layer generated by curing a polymerizable composition for forming the primer layer, and a photochromic layer containing a photochromic compound in this order, in which the polymerizable composition for forming the primer layer contains a component A: a polyisocyanate, a component B: a hydroxy group-containing polymerizable compound, and a component C: a polymerizable compound having a viscosity of 100 cP or less and being selected from the group consisting of (meth)acrylates and vinyl ethers.

Disclosed herein are isotactic polyvinyl ethers and improved methods of making same. The method disclosed herein can produce polyvinyl ethers having a higher isotacticity as compared to polyvinyl ethers prepared with conventional methods.

A Brønsted-Lowry acid initiator system for cationic polymerization of an ethylenically unsaturated monomer involves an initiator having a structure of Formula (I) in an anhydrous polymerization medium:

##STR00001## where: M is tantalum (Ta), vanadium (V) or niobium (Ni); R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same or different and are independently H, F, Cl, Br, I, alkyl or aryl, or two or more of R.sub.2, R.sub.3, R.sub.4 and R.sub.5 on a same benzene ring are taken together to form a bicyclic, tricyclic or tetracyclic moiety with the benzene ring, with the proviso that all of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 on the same benzene ring are not H; L is absent or a molecule that coordinates to H.sup.+; and, x is 0 when L is absent, or x is 0.5 or more when L is present.

A Brønsted-Lowry acid initiator system for cationic polymerization of an ethylenically unsaturated monomer involves an initiator having a structure of Formula (I) in an anhydrous polymerization medium:

##STR00001## where: M is tantalum (Ta), vanadium (V) or niobium (Ni); R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same or different and are independently H, F, Cl, Br, I, alkyl or aryl, or two or more of R.sub.2, R.sub.3, R.sub.4 and R.sub.5 on a same benzene ring are taken together to form a bicyclic, tricyclic or tetracyclic moiety with the benzene ring, with the proviso that all of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 on the same benzene ring are not H; L is absent or a molecule that coordinates to H.sup.+; and, x is 0 when L is absent, or x is 0.5 or more when L is present.

A Brønsted-Lowry acid initiator system for cationic polymerization of an ethylenically unsaturated monomer involves an initiator having a structure of Formula (I) in an anhydrous polymerization medium:

##STR00001## where: M is tantalum (Ta), vanadium (V) or niobium (Ni); R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are the same or different and are independently H, F, Cl, Br, I, alkyl or aryl, or two or more of R.sub.2, R.sub.3, R.sub.4 and R.sub.5 on a same benzene ring are taken together to form a bicyclic, tricyclic or tetracyclic moiety with the benzene ring, with the proviso that all of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 on the same benzene ring are not H; L is absent or a molecule that coordinates to H.sup.+; and, x is 0 when L is absent, or x is 0.5 or more when L is present.

A draw solute may have a low viscosity, and can be circulated during a forward-osmosis water treatment, and has a sedimentation under heating and a higher osmotic pressure than that of seawater, when used as a draw solution. A draw solute may include at least one of vinyl ether polymer containing an oxyethylene chain in a side chain and having a number average molecular weight (Mn) of 13,000 or less.

A draw solute may have a low viscosity, and can be circulated during a forward-osmosis water treatment, and has a sedimentation under heating and a higher osmotic pressure than that of seawater, when used as a draw solution. A draw solute may include at least one of vinyl ether polymer containing an oxyethylene chain in a side chain and having a number average molecular weight (Mn) of 13,000 or less.

[Object] To provide a method for producing a vinyl ether polymer containing a hydrocarbon group in a stable and efficient manner, wherein decomposition of the monomer and generation of polyacetal are suppressed.

[Means for solving problem] The method for producing a vinyl ether polymer containing a hydrocarbon group according to the present invention comprises the step of polymerizing vinyl ether represented by the following formula (1):

##STR00001## wherein R.sup.1 represents an aliphatic hydrocarbon group having 1 to 10 carbons or an alicyclic hydrocarbon group having 3 to 10 carbons,
in the presence of water as a polymerization solvent and an organic azo-based compound as a radical polymerization initiator, under pH of 6 or more.

[Object] To provide a method for producing a vinyl ether polymer containing a hydrocarbon group in a stable and efficient manner, wherein decomposition of the monomer and generation of polyacetal are suppressed.

[Means for solving problem] The method for producing a vinyl ether polymer containing a hydrocarbon group according to the present invention comprises the step of polymerizing vinyl ether represented by the following formula (1):

##STR00001## wherein R.sup.1 represents an aliphatic hydrocarbon group having 1 to 10 carbons or an alicyclic hydrocarbon group having 3 to 10 carbons,
in the presence of water as a polymerization solvent and an organic azo-based compound as a radical polymerization initiator, under pH of 6 or more.

The present invention relates to a polymer electrolyte for a secondary battery and a lithium secondary battery including the same, and to a polymer electrolyte for a secondary battery, which includes unit A derived from a poly(ethylene oxide)-based polymer, and a lithium secondary battery including the same.