Ketal ester derivatives

A polycarbonate one or more repeat units IA, IB, or a combination thereof:

• wherein
• R1 is a divalent linear, branched, or cyclic alkyl group having 1 to 36 carbon atoms, a linear or branched alkenyl group having 1 to 36 carbon atoms, an aryl group, or an alkaryl group having from 7 to 36 carbon atoms;
• R2 is a covalent bond or a linear, branched, or cyclic alkyl group having 1 to 18 carbon atoms, a linear or branched alkenyl group having 1 to 18 carbon atoms, an aryl group, or an alkaryl group having from 7 to 18 carbon atoms;
• R3 is hydrogen, alkynyl, or a linear, branched, or cyclic alkyl group having 1 to 18 carbon atoms, a linear or branched alkenyl group having 1 to 18 carbon atoms, an aryl group, or an alkaryl group having from 7 to 18 carbon atoms;
• R4 is a group having the formula
• wherein
• a is 0 or 1 and
• R5, R6, R7, R8, R9, and R10 are independently hydrogen, alkynyl, or linear, branched, or cyclic alkyl groups having 1 to 18 carbon atoms, linear or branched alkenyl groups having 1 to 18 carbon atoms, aryl groups, or alkaryl groups having from 7 to 18 carbon atoms;
• α and α′ are independently integers of 1 to about 100;
• and
• γ is an integer of 1 to about 30 and γ is the same or different for repeat unit IA and repeat unit IB.