Monomer mass balances determination

Values for the propagation rate constant can be determined from bulk or solution experiments. Values of k have been published for a wide variety of monomers as a function of temperature. With standard emulsion polymerization recipes the value of [M]p is determined from equilibrium swelling measurements if a free monomer phase is present and by a mass balance if all the monomer is in the polymer particles. One normally assumes that [M] is not dependent on particle size in latexes comprised of different-sized particles. This assumption will be questionable in some systems, especially those involving high-swelling particles. 

To obtain the true concentrations zin, a system of equations much more complicated than for pure components must be solved. Again, the true monomer concentrations zn are the key concentrations. After they have been determined, the concentrations of the other species can be derived by the equilibrium conditions Eqs (13.24) and (13.39). For each component, a true monomer concentration exists, no matter if it associates or not. Therefore, one equation must be available for each component. The first equation of the system is a simple mass balance. The sum of the true concentrations of all species is 1 ... 

For low molecular mass amphiphiles, hydrophobic interactions and surface effects determine the critical concentration at which micellar aggregates are favored over the molecularly dispersed amphiphilic solutes. For polysurfactants, however, the amphiphiles are linked together and the dynamic exchange of associated and non-associated amphiphilic monomer units is prevented. Consequently the micelle formation does not only depends on the hydrophilic/ hydrophobic balance of the monomer... 

Isothermal phase-change calorimeters based on liquid + vapour equilibria have been used for the determination of energies of polymerization. The monomer was sealed into an ampoule immersed in the calorimetric liquid e.g. carbon tetrachloride, benzene, toluene) contained in a tube, which was suspended from a balance and surrounded by vapour of the same refluxing liquid. As the polymerization proceeded the heat liberated by the reaction caused liquid to vaporize from the tube and was measured by the consequent loss in mass. ... 

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