Synthesis of High Molecular Weight Poly(glycerol monomethacrylate) via RAFT Emulsion Polymerization of Isopropylideneglycerol Methacrylate

Abstract

High molecular weight water-soluble polymers are widely used as flocculants or thickeners. However, synthesis of such polymers via solution polymerization invariably results in highly viscous fluids, which makes subsequent processing somewhat problematic. Alternatively, such polymers can be prepared as colloidal dispersions; in principle, this is advantageous because the particulate nature of the polymer chains ensures a much lower fluid viscosity. Herein we exemplify the latter approach by reporting the convenient one-pot synthesis of high molecular weight poly(glycerol monomethacrylate) (PGMA) via the reversible addition–fragmentation chain transfer (RAFT) aqueous emulsion polymerization of a water-immiscible protected monomer precursor, isopropylideneglycerol methacrylate (IPGMA) at 70 °C, using a water-soluble poly(glycerol monomethacrylate) (PGMA) chain transfer agent as a steric stabilizer. This formulation produces a low-viscosity aqueous dispersion of PGMA–PIPGMA diblock copolymer nanoparticles at 20% solids. Subsequent acid deprotection of the hydrophobic core-forming PIPGMA block leads to particle dissolution and affords a viscous aqueous solution comprising high molecular weight PGMA homopolymer chains with a relatively narrow molecular weight distribution. Moreover, it is shown that this latex precursor route offers an important advantage compared to the RAFT aqueous solution polymerization of glycerol monomethacrylate since it provides a significantly faster rate of polymerization (and hence higher monomer conversion) under comparable conditions.

Triphilic pentablock copolymers with perfluoroalkyl segment in central position

“…But as shown in Table 1 the molar mass increases upon deprotection from 20,800 to 37,200 g/mol. This is an apparent increase of the molar mass also observed by GPC in DMF for other block copolymers upon PGMA deprotection 50 . A possible reason is that DMF is a better solvent for PGMA containing block copolymers compared with the respective species containing PSMA blocks.…”

“…This is an apparent increase of the molar mass also observed by GPC in DMF for other block copolymers upon PGMA deprotection. 50 A possible reason is that DMF is a better solvent for PGMA containing block copolymers compared with the respective species containing PSMA blocks. Thus, PGMA containing block copolymers occupy a larger hydrodynamic volume.…”

RAFT Dispersion Polymerization in Silicone Oil

“…[55][56][57] Thus it seems likely that the few cases where the onset of micellization has apparently coincided with the presence of higher order morphologies (rather than the formation of spheres) are actually artifacts caused by the ingress of hot solvent at elevated temperature into the nanoparticle cores. 21,[58][59][60] Each aliquot removed for these kinetic studies was also analyzed via GPC to assess the evolution of Mn and Mw/Mn during the DMA polymerization (see Figure 3b). A linear evolution of Mn with conversion was observed, as expected for a RAFT polymerization.…”

The emulsion polymerization induced self-assembly of a thermoresponsive polymer poly(N-vinylcaprolactam)

“…The synthesis of high molecular mass PNVCL Surfactant-free RAFT emulsion polymerization is known to be well-suited to the synthesis of high molecular mass polymers. [36][37][38][39] Observations from previous polymerizations were used to design the synthesis of a high molecular weight polymer. The selected monomer/PEG 113 -X/initiator ratio was 6000/1/0.9 and the initial NVCL concentration was 0.1 g ml −1 .…”

“…Surfactant-free RAFT/MADIX emulsion polymerization has been recently reviewed by Zhou et al 37 This method has been used, for example, to produce high molecular mass polystyrene 38 and poly(glycerol monomethacrylate). 39 Here, the surfactant-free RAFT/MADIX emulsion polymerization of NVCL is studied for the synthesis of high molecular mass PNVCL. Another appealing aspect of surfactant-free RAFT emulsion polymerization, and the main motivation for this work, is the formation of particles during synthesis.…”