Calculate the concentration of benzoyl peroxide required to prepare polystyrene with a number-average molar mass of 750 kg mol−1 by bulk polymerization at 60 °C. Assume: (i) the initiator is 60% efficient; (ii) the rate coefficients for initiator dissociation, propagation and termination are, respectively, 2 × 10−6 s−1, 341 dm3 mol−1 s−1 and 4 × 107 dm3 mol−1 s−1; (iii) the density of styrene at the polymerization temperature is 0.88 g cm−3; and (iv) that termination by disproportionation, and chain transfer to initiator and monomer, are negligible. Radical Polymerization 119 (b) Calculate initial values of (i) the radical concentration and (ii) the rate of bulk polymerization expected for bulk polymerization