Particle number polymeric reagents

Process models are also important components of reactor control schemes. Kiparissides et al. [17] and Penlidis et al. [16] have used reactor models for control simulation studies. Particle number and size characteristics are the most difficult latex properties to control. Particle nucleation can be very rapid and a strong function of the concentration of free emulsifier, electrolytes and various possible reagent impurities. Hence the control of particle number and the related particle surface areas can be a difficult problem. Even with on-line light scattering, chromatographic [18], surface tension and/or conversion measurements [19], control of nucleation in a CSTR system can be difficult. The use of a pre-made seed or an upstream tubular reactor can be utilized to avoid nucleation in the CSTR and thereby imjHOve particle number control as well as increase the number of particles formed [20-22]. Figures 8.6 and 8.7 illustrate open-loop CTSR systems for the emulsion polymerization of methyl methacrylate with and... [Pg.564]

Figo 7o Dependence of the particle number on sodium dodecyl sulfate concentration in aqueous phase polymerization of MMA at various monomer concentrations. Initial monomer concentrations, [M]q, are O 0,100, O 0,080M, Initiator system hydrogen peroxide-iron (II) (Fenton s reagent), with rate of initiation, R = lo6 x 10 radicals/l/seco Crosshatched region indicates monodisperse particle size distributions. [Pg.85]