Purification means

A method of purifying crude polymers derived from acyloxystyrene or alkoxy styrene of the group consisting of

• wherein R is either —C(O)R5 or —R5;
• as a homopolymer or a copolymer with one or more of the following monomers:
• an acrylate monomer having the formula II,
• and/or with one or more ethylenically/unsaturated copolymerizable monomers taken from the group consisting of styrene, 4-methylstyrene, styrene alkoxide wherein the alkyl portion is C1-C5 straight or branch chain, tert.-butylstyrene, cyclohexyl acrylate, tert.-butyl acrylate, tert.-butyl methacrylate, maleic anhydride, dialkyl maleate, dialkyl fumarate and vinyl chloride, wherein:
• i) R1 and R2 are the same or different and independently selected from the group consisting of:
• hydrogen,
• fluorine, chlorine, bromine,
• alkyl and fluoroalkyl group having the formula CnHxFy where n is an integer from 1 to 4, x and y are integers from 0 to 2n+1, and the sum of x and y is 2n+1,
• phenyl, and tolyl;
• ii) R3 is selected from the group consisting of:
• hydrogen,
• methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, and tert.-butyl;
• iii) R4is~selected from the group consisting of methyl, ethyl, n-propyl, iso-propyl, n-butyl, i-butyl, tert-butyl, t-amyl, benzyl, cyclohexyl, 9-anthacenyl, 2-hydroxyethyl, cinnamyl, adamantyl, methyl or ethyl or hydroxyl adamantyl, isobornyl, 2-ethoxyethyl, n-heptyl, n-hexyl, 2-hydroxypropyl, 2-ethylbutyl, 2-methoxypropyl, 2-(2-methoxyethoxyl), oxotetrahydrofuran, hydroxy trimethylpropyl, oxo-oxatricyclo non yl, 2-naphthyl, 2-phenylethyl, and phenyl;
• and
• iv) R5 is C1-C4 alkyl
• consisting essentially of subjecting said crude polymer, after polymerization thereof, to a fractionalization procedure wherein said crude polymer in an alcoholic solvent is (a) suspended therein and additional solvent is added, (b) heated and/or stirred for a sufficient period of time to permit dissolution of the undesirable monomeric impurities and oligomers in said crude polymer, (c) cooling the resultant mixture, (d) separating the alcoholic solvent from said polymer and (e) repeating said steps (a)-(d)until the polydispersity value of the purified polymer is about 10% less than that polydispersity value of the crude polymer.