The kinetics of the early stage of dispersion polymerization in supercritical CO2 as monitored by turbidimetric measurements, 1. Method

Influence of structure and solubility of chain transfer agents on the RAFT control of dispersion polymerisation in scCO2

“…In the absence of DDMAT, all other conditions remaining the same, a turbid system was observed within the rst minute, in agreement with literature observations, 44,45 and led to complete obscurity (i.e. no observable light passed through the view cell) within 10 minutes of reaction start ( Fig.…”

“…42 At that time nucleation has already occurred. In fact, Ballauff and Fehrenbacher have previously monitored the early stages (#300 s) of MMA conventional radical dispersion polymerisation in scCO 2 via turbidimetry, 44,45 and have observed that nucleation started before 0.1% MMA conversion.…”

“…At this point the medium is still homogeneous and the continuous phase is the reaction locus. 44,45 As a result, some chains will certainly escape the expected RAFT equilibrium, and grow by conventional radical polymerisation to yield a high molecular weight population, which will nucleate very efficiently into PMMA particles and form a polymer rich phase. What then happens is that DDMAT, AIBN and MMA could begin to diffuse into those seed particles.…”

Detailed modelling of MMA dispersion polymerization in supercritical carbon dioxide

“…(3) Particle nucleation is not accounted for, i.e., a number of particles equal to the final experimental value is assumed to be present from the beginning. This is because the nucleation period where the particle number changes significantly is expected to be very short in these systems (Fehrenbacher et al, 2000;Fehrenbacher and Ballauff, 2002). As a consequence, the role of the stabilizer in particle formation and stabilization is not explicitly considered.…”

Stabilizer‐Free Dispersion Copolymerization of Maleic Anhydride and Vinyl Acetate. II. Polymerization Features

“…[1][2][3][4][5][6][7][8] In contrast to the multiplephase emulsion polymerization, dispersion polymerization starts from a clear homogeneous solution containing monomer(s), initiator and stabilizer; subsequently, it becomes a turbid heterogeneous colloidal system. The kinetics and mechanism of dispersion polymerization is thus more complex and poorly understood as compared to that of emulsion polymerization.…”