Butyl methacrylate water-dispersed

In Fig. 12 the stability of the concentrated emulsions is plotted against the concentration of methyl cellulose in the aqueous continuous phase. Obviously the viscosity of the continuous phase increases with increasing concentration. Concentrated emulsions did not form for high concentrations of methyl cellulose owing to the difficulty of incorporating the dispersed phase into the continuous phase. For instance, styrene-water and n-butyl methacrylate-water did not form concentrated emulsions for methyl cellulose concentrations in the... 

Fig. 12. Weight per cent of bulk phases separated from o/w concentrated emulsions by heating for 24 h at 50 °C plotted against the concentration of methyl cellulose in the aqueous phase containing SDS (3.47 x 10-1 mol T1 water). The concentrated emulsions were prepared at 25 °C and had a volume fraction of the dispersed phase of 0.9. O and denote styrene and n-butyl methacrylate as the dispersed phases of concentrated emulsions, respectively...

Figure 14.8 Two plots which summarize the influence of blend composition on the drying rates for mixtures of hard and soft latex particle dispersions. The hard latex is poly (methyl methacrylate) (d = 110 nm), and the soft latex is poly-[(butyl methacrylate) o-(hutyl acrylate)] (d = 43 nm, Tg = —33 C). Each data point represents a snapshot of the drying process, (a) refers to the instantaneous rate of water evaporadon at SO wt%, 7S wt% and 90 wt% solids, for blends cotiprising different volume fracdons (4 hud) of hard latex, (b) refers to the time needed for the dispersions, originally at S wt% to reach SO wt%, 7S wt% and 90 wt% solids at 22 °C, 50% reladve humidity in sdll air. Both plots indicate that c. 1 1 mixtures dry at the slowest rate...

The use of either styrene or butyl methacrylate as monomer led to stable latexes that were not covered by silica particles. Bon and coworkers proposed a mechanism for the solids-stabilized, or Pickering, emulsion polymerization that effectively combines coagulative nucleation with heterocoagulafion throughout the polymerization process. The growing latex particles become unstable and collide irreversibly with the nanoparticles that are dispersed in the water phase. The key to successful polymerization is that this collision process is fast with respect to the timescales of particle nucleation and growth. 

Figure 5.21 TEM images of poly(w-butyl methacrylate)-grafted MWCNTs with azido groups (MWCNT-Az-PnBMA) (a), MWCNTs grafted with both poly( -butyl methacrylate) and poly(ethylene glycol) brushes (MWNT-PnBMA-PEG) (b, c). (d) Cartoon for the local phase separation and assembly of amphiphilic polymer brushes into Janus polymer structures on CNTs as shown in (c) (marked by arrows), (e) Photograph of MWCNT-PnBMA-PEG dispersed in a mixed solvent of water (upper layer) and chloroform (bottom layer). Reprint with permission from Zhang et al...

An acrylic-alkyd graft copolymer which is water-dispersible was prepared by Walus (30) by copolymerizing methyl methacrylate, butyl methacrylate and methacrylic acid in the presence of an epoxy-modified dehydrated castor oil alkyd which was pre-reacted with lEM. When formulated with NH this gives an air-dry water-dispersible alkyd... 

Hybrid aqueous dispersions were prepared containing both acrylic resins and polyurethane to provide enhanced properties for coating applications. Nanosized (approximately 50 mn) hybrid latexes were prepared at 30 C by the redox-initiated miniemulsion polymerisation of n-butyl methacrylate monomer in the presence of a urethane prepolymer. A stabiliser, of low molecular weight and low water solubility, was required to obtain stable particles of the required size. 7 refs. 

Living polymerization in water also led to polymers with a relatively narrow molecular mass distribution (1.1-1.3) and molecular masses, which showed linear increase with conversion, indicating the living character of this polymerization [320]. Recently, Matyjaszewski et al. reported both reverse and direct ATRP of n-butyl methacrylate in an aqueous dispersed system via the miniemulsion approach, characterized by a linear increase of the molecular mass with conversion and a narrow distribution of molecular masses [321]. The suspension-type process of living polymerization of MMA in water not only led to well controlled and high molecular masses and low PDIs, but also the polymerization proceeded without the addition of Al(0-i-Pr)3 and clearly faster than ATRP in organic solvents [322]. 

Kawaguchi S, Winnik MA, Ito K. Dispersion copolymerization of n-butyl methacrylate with poly(ethylene oxide) macromonomers in methanol-water, comparison of experiment with theory. Macromolecules 1995 28 1159-1166. 

Numerous recipes have been pubUshed, primarily ia the patent Hterature, that describe the preparation of acrylate and methacrylate homopolymer and copolymer dispersions (107,108). A typical process for the preparation of a 50% methyl methacrylate, 49% butyl acrylate, and 1% methacrylic acid terpolymer as an approximately 45% dispersion ia water begias with the foUowiag charges ... 

Butyl acrylate-methyl methacrylate copolymer latices with a core-shell structure were prepared by a sequential emulsion polymerisation technique. SEM and transmission electron microscopy studies undertaken on the polymer dispersions, powders obtained by spray drying and latices prepared by redispersing the powders in water revealed the influence of polymerisation parameters on the micromorphology of the starting latices, and correlations between the dimensional and micromorphological characteristics of the starting latices, the powders and the redispersed latices. 8 refs. 

H) TeRP in aqueous dispersed systems The TeRP proceeds by the two aaivation-deactivation processes, namely, thermal dissodation of the C-TeCHs terminal bond and degenerative transfer of the terminal -TeCHs group. However, when an external source of free radicals is used at low temperature, it only proceeds by degenerative transfer. Okubo a used a water-soluble poly(methacrylic add) with a -Te-CH3 terminal group to synthesize poly(/i-butyl acrylate) latex partides by chain extension of the hydrophilic segment in emulsion polymerization. The system resulted in very small partides with controlled polymer chains exhibiting an amphiphilic stmcture. 

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