Novel process for producing anhydride-containing polymers for radiation sensitive compositions

A polymerization process for preparing an anhydride-containing polymer, the process comprising:

• a) providing a reaction mixture comprising:
• an ethylenically unsaturated anhydride monomer, at least one ethylenically unsaturated non-anhydride monomer, a free radical initiator, and an alkyl substituted THF solvent of formula 1:
• 8
• where R1, R2, R3, and R4 are independently chosen from the group consisting of hydrogen and C1-C4 linear or branched alkyl with the proviso that at least one of R1, R2, R3, and R4 is not H;
• and optionally a co-solvent;
• b) polymerizing the reaction mixture;
• and
• c) removing unreacted monomers, the alkyl substituted THF solvent, and any low-boiling volatile reaction products having a lower boiling point than the boiling point of any optional co-solvent employed.