Summary The plasma-initiated emulsion polymerization of MMA in the presence of 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) was first
investigated. The polymers were characterized by GPC, 1H NMR, DSC and SEM. The results exhibit controlled polymerization characters: well-controlled molecular weight, relatively
narrow polydispersity, molecular weight linearly increasing with conversion and successful chain extension reactions. The
influence of the amount of the sodium dodecyl sulfate (SDS), CPDN concentration, plasma duration time on the polymerization
rate, and micro-shape of the particle was investigated in this work. The plasma-initiation emulsion polymerization of octyl
acrylate (OA) in the presence of CPDN is also carried out. 相似文献
Summary
This article deals with the living radical emulsion
photopolymerization of methyl methacrylate (MMA) using a RAFT
agent which plays the role of an initiator in the absence of an
additional thermal initiator, a chain-transfer agent, and a
surfactant. The mechanism of the formation of stable spherical
polymer beads without coagulation in the absence of a surfactant
and the effects of the added surfactant are studied. The
molecular weights of the prepared PMMA beads are in the same
range (Mn: 105
- 106 g/mol) as those obtained from a
conventional emulsion polymerization. However, the molecular
weight distribution
(Mw/Mn;
polydispersity index; PDI) is controlled to be less than 2.0.
The polymer beads in diameter was significantly reduced from 300
nm without a surfactant to decreased to 50 nm upon the addition
of sodium dodecyl sulfate (SDS) keeping the molecular weight and
the molecular weight distribution constant. Also, the addition
of SDS in the preparation of PMMA colloid results in the
enhancement of the stability by exhibiting increased -potential
values in water 相似文献
Summary: Reversible addition fragmentation chain transfer (RAFT) polymerizations of methyl acrylate (MA) in solution containing either 22 vol.‐% CO2 or toluene were performed at 80 °C and 300 bar using cumyl dithiobenzoate (CDB) at concentrations between 1.8 × 10?3 to 2.5 × 10?2 mol · L?1 as the RAFT agent. Product molecular weight distributions and average molecular weights indicated the successful control of MA polymerization in CO2, even at low CDB concentrations. RAFT polymerization rates were strongly retarded by CDB and were lower in CO2 than in toluene solution. The enhanced fluidity associated with the addition of CO2 to the polymerizing system provided access to mechanistic details of RAFT polymerization. The data of the present study into MA, together with our recent results on RAFT polymerization of styrene in solution of CO2 and of toluene, suggest that self‐termination of intermediate RAFT radicals is responsible for retardation in case of high concentrations of this intermediate and in case of enhanced fluidity, which may be achieved by polymerization in solution of CO2.
