Within the field of ROP there remain many unanswered questions, including the controlled synthesis of high-molar-mass poly(β-butyrolactone) with a sufficiently reactive yet selective initiator, the user of ‘fast initiators’ in a lactide polymerization that function with high selectivity in the monomer/polymer melt, and identification of the mechanisms of organocatalytically prompted polymerizations.
Source: wiktionary