Previous report has shown that the low concentration of nitroxide radical on flat surfaces results in an insufficient concentration of deactivator to provide adequate control during the NMRP reaction (23).
Experimental conditions and results for the NMRP of PSMA from [Fe.sub.3][0.sub.4] nanoparticles.
The above results revealed that the process of surface-initiated NMRP of St and MA was controlled.
The core reaction in NMRP is the equilibrium between active and dormant species (Eq.
The experimental data for conversion versus time, [M.sub.n] and [M.sub.w] versus conversion, and PDI versus conversion for the NMRP of styrene at 130[degrees]C and [TEMPO]/[BPO] = 0.9, 1.1, and 1.3 are shown in Figures 13-16.
(1996a,b) had conducted NMRP of styrene at 125[degrees]C, [TEMPO] /[BPO] = 1.1 and 1.3, as part of their kinetic studies.
In order to get a better feel about how narrow the polydispersity values are in NMRP, values from thermal polymerization of styrene (in the absence of initiator and nitroxide), as well as thermal NMRP (nitroxide-mediated polymerization of styrene in the absence of initiator) are also presented in Figure 17b and c.
In developing an NMRP miniemulsion polymerization process suitable for industrial application, it would be desirable to have: (1) a high degree of chain livingness, to enable synthesis of complex microstructures; (2) a high final monomer conversion (>95%) to minimize the cost of monomer stripping; (3) a reasonably short total process time to maximize reactor throughput; and (4) low polymer polydispersity.
Dead chains in NMRP are generated primarily from two mechanisms: irreversible termination and disproportionation.
Experimental and modeling studies conducted in our laboratory have led us to a better understanding of the critical issues in designing miniemulsion NMRP processes.