Aqueous Dispersions of Nonspherical Polyethylene Nanoparticles from Free‐Radical Polymerization under Mild Conditions

Abstract

A radical idea: Free‐radical polymerization of ethylene usually requires severe conditions. Here, the efficiency of this reaction was investigated under mild conditions (less than 250 bar) in water for the production of stable polyethylene (PE) aqueous dispersions (see picture, Dp=particle diameter). Latexes of PE nanoparticles with various shapes (cylinder or sphere) and solid contents up to 40 % were prepared.

Poly(vinyl acetate-co-ethylene) particles prepared by surfactant-free emulsion polymerization in the presence of a hydrophilic RAFT/MADIX macromolecular chain transfer agent

“…We successfully undertook several studies based on this concept employing hydrophilic polymer chains obtained by reversible addition-fragmentation chain transfer (RAFT) and macromolecular design by interchange of xanthates (MADIX) in order to produce industrially relevant surfactant-free formulation for the production of film forming latex such as poly (meth)acrylics, [38][39][40][41] poly(vinylidene fluoride) 42 and poly(vinylidene chloride). [43][44][45] In the present paper, we apply this strategy for the first time to the emulsion copolymerization of ethylene and vinyl acetate for the production of VAE, building on our recent works on the polymerization of ethylene by free radical polymerization in water under mild conditions (i.e., temperature <90°C and ethylene pressure <250 bar), [46][47][48] and on PVAc 49,50 and polyethylene (PE) 51 particle synthesis mediated by macromolecular chain transfer agents (macroCTAs). The reactivity of these two monomers restricts the choice of potential macroCTAs to hydrophilic polymer chains carrying dithiocarbonate or dithiocarbamate end groups.…”

New, Aqueous Radical (Co)Polymerization of Olefins at Low Temperature and Pressure

“…Polymerizations can also be performed both in bulk and in aqueous emulsion [3][4][5][6][7][8][9][10][11]. Not only linear polymers but also nanocomposites have been prepared by the polymerization of ethylene in emulsion [12][13][14][15]. There have been many attempts to carry out radical ethylene polymerization under milder conditions (<100 • C and <1000 bar) [16].…”

“…The aforementioned aqueous emulsion polymerization of olefines applies a temperature above 80 • C, pressure around and above 200 bars, and high amounts of hardly removable surfactants [12][13][14][15][16]. Cyclodextrins (CDs) are widely used to complex and solubilize different hydrophobic substances, even monomers, and polymers [30][31][32].…”

Synthesis of ethylene and butyl methacrylate‐based copolymer by emulsion polymerization

“…Copolymerization of ethylene with polar monomer is a major challenge and only a few studies on free‐radical copolymerization of ethylene with polar monomer have been carried out in aqueous medium under relatively high pressure . Also studies on the synthesis of polyethylene based copolymers with precise control over heterogeneity as well as on kinetic study on copolymerization is still scanty.…”