CHEM 4214 Lecture Notes - Lecture 11: Living Free-Radical Polymerization, Gibbs Free Energy, Radical Polymerization
Document Summary
Friday, february 12, 2016: anionic polymerization, cationic polymerization move active site to end, controlled radical polymerization for normal chain growth polymerization. To control, we need to have rp >> rt to have living polymerization, don"t want termination. Assume from book, kp ~ 103 l/mol s kt ~ 107 l/mol s. X = halide: stable free-radical polymerization (sfrp) Easy control by temperature (>125 degrees c, polymer) tempo usually just works w/ vinyl monomers --> limited. Equilibrium issues dp = depolymerization can cancel out the concentrations of polymers. = for pure solvent or pure reactant (w/o rxn); base gibbs free energy. Polymers gibbs free energy need to satitisfy this to have polymerization. Furthermore, to kave kpoly much greater than 0, need can achieve this in 2 ways which is more likely? before, monomer is free, but after polymerized, more constrained. -> 2nd term can"t be satisfied so focus on enthalpy double bond has more energy than single bond.
