Past exam of the chemistry course of the year 4 of the natural sciences course of the University of Cambridge / 2022 / Paper 2 / Section A / 19 / c

The ideal number-average molar mass is approximately 25.11 kg mol${}^{-1}$. Quantitative uptake of 100 lactide and 100 styrene molecules per bifunctional initiator givesB has formula ${\mathrm{C}}_{17}{\mathrm{H}}_{27}\mathrm{N}{\mathrm{O}}_2$. Lactide's entire cyclic diester mass is incorporated; multiplying its molar mass by two again would double-count its two lactyl units. The estimate assumes quantitative initiation, conversion, nitroxide recapping and no chain transfer or loss of chain-end fragments.