Free radical retrograde precipitation copolymers and process for making same

A single stage free radical retrograde precipitation polymerization process for producing a copolymer comprising:

• a) admixing
• 1) a solvent,
• 2) a free-radical-forming agent,
• 3) (meth)acrylic acid,
• 4) and at least one non-acid ethylenically unsaturated monomer;
• b) initiating a free-radical precipitation polymerization to form a plurality of polymer radicals;
• c) precipitating a copolymer from said polymer radicals;
• d) maintaining the admixture of reactants at a temperature above the lower critical solution temperature of said admixture;
• and
• e) controlling the reaction conditions of said admixture to control the rate of propagation of the polymer.

A free radical retrograde precipitation polymerization process for producing a block copolymer comprising:

• a) admixing
• 1) a solvent,
• 2) a free-radical-forming agent,
• 3) at least one ethylenically unsaturated monomer;
• b) initiating a free-radical precipitation polymerization to form a plurality of polymer radicals;
• c) precipitating a polymer from said polymer radicals;
• d) maintaining the admixture of reactants at a temperature above the lower critical solution temperature of said admixture;
• e) controlling the reaction conditions of said admixture to control the rate of propagation of the polymer;
• f) rapidly cooling the reactor contents to below the lower critical solution temperature, following at least 3 times the initiator half life to produce the first monomer into polymer,
• g) admixing a second monomer mixture containing at least one ethylenically unsaturated monomer into the cooled reactor contents;
• h) heating the reactor contents above the lower critical solution temperature to continue polymerization.