4. a) Consider the following reactivity ratios for the copolymerization of three monomer pairs: Case I 11 rl (MI) 0.0 2.0 0.7 1.0 r2 (M2) 0.0 0.5 0.3 1.0 111 iv Specify the type of copolymers that would possibly result in the cases i to iv. Which of the two monomers (M1 or M2) would be present in higher mole fraction in each case. Explain your answer. Assume that polymer samples are isolated both at low and high conversions with feed ratio 1:1, respectively