2 edition of Studies of block copolymer stabilizers for dispersion polymerization found in the catalog.
Studies of block copolymer stabilizers for dispersion polymerization
Written in English
Thesis(Ph.D.) - Loughborough University of Technology 1977.
|Statement||by G. Taylor.|
The two monomers were homopolymerized and then copolymerized. The obtained homopolymers and the copolymer were mixed with nitrocellulose and evaluated using thermal analysis and Bergmann–Junk techniques as propellant stabilizers in comparison with the common stabilizer Cited by: 9. Dispersion polymerization provides an efficient route for synthesis of spherical polymer particles in the micron-size range with narrow size polydispersities and high conversions. The particles that result from a dispersion polymerization are typically larger than those produced by emulsion polymerization and range in size from nm to 15 μm.
Traditionally, post-polymerization processing routes have been used to obtain a wide range of block copolymer morphologies. However, this self-assembly approach is normally performed at rather low copolymer concentration, which precludes many potential applications. Herein, we report a Cited by: 7. Ionization of the carboxylic acid end-group on the PGMA stabilizer block induces a worm-to-sphere transition, which in turn causes immediate degelation. This morphological transition is fully reversible as determined by TEM and rheology studies and occurs because of a subtle change in the packing parameter for the copolymer by:
These observations suggest that the rate of copolymer chain exchange depends on the degree of polymerization of the core-forming block. Relatively slow copolymer chain exchange was also observed at 80 °C, which is below the T g of the core-forming PMMA block as determined by DSC studies. Systematic variation of the mean degree of polymerization of the core-forming PBzMA block enabled control over the mean particle diameter: small-angle X-ray scattering (SAXS) analysis indicated that PLMA 39 –PBzMA 97 and PLMA 39 –PBzMA formed well-defined, non-interacting spheres at 25 °C with core diameters of 21 ± 2 nm and 48 ± 5.
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Near-monodisperse micrometer-sized polystyrene particles were produced by dispersion polymerization in alcoholic media using poly(2-(dimethylamino)ethyl methacrylate-b-alkyl methacrylate) copolymer stabilizers.
The effect of varying stabilizer concentration, copolymer composition, solvent, and reaction temperature on latex particle size was by: Studies of block copolymer stabilizers for dispersion polymerization Anionic polymerization techniques have been used to prepare AB block copolymers of polystyrene and poly[dimethyl siloxane] having well-defined molecular weight and composition, and narrow molecular weight : Graham Taylor.
Poly(styrene)-b-poly(acrylic acid) block copolymers were synthesized by nitroxide-mediated radical polymerization and employed as stabilizers in the emulsion polymerization of styrene.
The most successful types of stabilizer for non-aqueous dispersion polymerization have been based on block or graft copolymers, one component of which is the soluble stabilizing moiety. The ‘anchor’ component is insoluble in the continuous phase and is adsorbed on, or absorbed into, the disperse phase.
In this Perspective, we discuss the recent development of polymerization-induced self-assembly mediated by reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization. This approach has quickly become a powerful and versatile technique for the synthesis of a wide range of bespoke organic diblock copolymer nano-objects of controllable size, morphology, Cited by: A general overview of emulsion and dispersion polymerization in an aqueous and organic medium with ionic and nonionic block copolymers is presented for the preparation of electrosteric and.
Figure 1. (a) Synthesis of spherical diblock copolymer nanogels via RAFT aqueous dispersion polymerization at 30 or 40 °C. (b) Intensity average size distribution obtained using DLS.
(c) AFM image of the dried nanogel particles. Adapted with permission from ref Journal of the American Chemical Society Perspective. Poly(glycerol monomethacrylate-blockhydroxypropyl methacrylate) [PGMA–PHPMA] diblock copolymer vesicles are prepared by RAFT aqueous dispersion polymerization at 70 °C and then used as precursors for chain extension experiments with a third comonomer.
For self-blocking experiments conducted with water-soluble HPMA, good living character is obtained, as judged by the relatively low Cited by: Well defined AB block copolymers of polystyrene and poly(dimethyl siloxane) have been used as stabilizers in the dispersion polymerisation of styrene in n -alkanes.
The dependences of the particle size and particle size distribution on the relative block lengths in the copolymer have been by: 6. Raw dispersions are produced by dispersion polymerization in the range of PTFE or a TFE copolymer in water. To insure a commercially viable product, the dispersion must be sufficiently stable for transportation, storage, and handling.
A series of emulsion polymerizations with varying stabilizer content suggests that a novel nucleation mechanism occurs in block-random copolymer-stabilized emulsion polymerizations, exhibiting distinctly different behaviors from block copolymers or conventional small-molecule : Connor A.
Sanders, Sean R. George, Gary A. Deeter, J. Campbell, Bernd Reck, Michael F. Cunningham. The early studies of block copolymers as a stabilizer in dispersion polymerization have been carried out by Barrett, Winnik et al.
and Piirma. After them, many researchers studied with various block copolymers under different reaction conditions , .Cited by: ABS copolymers consist of a dispersion of poly-butadiene rubber particles in a matrix of styrene–acrylonitrile copolymer.
Some of the SAN copolymer molecules become grafted to the rubber during polymerization. Abstract. Dispersion polymerization is an attractive method for producing micron-size monodisperse polymer particles in a single batch process.
Great progress in this field has been achieved over the past two decades. Block copolymers are normally prepared by controlled polymerization of one monomer, followed by chain extension with a different monomer(1) to form AB or ABC block copolymers. If you have not read the section on " Chain Extension " in the " Procedures for Initiation of an ATRP " you should return to that section if you wish to efficiently chain.
In polymer science, dispersion polymerization is a heterogeneous polymerization process carried out in the presence of a polymeric stabilizer in the reaction medium. Dispersion polymerization is a type of precipitation polymerization, meaning the solvent selected as the reaction medium is a good solvent for the monomer and the initiator, but is a non-solvent for the polymer.
RAFT dispersion polymerization of glycidyl methacrylate for the synthesis of epoxy-functional block copolymer nanoparticles in mineral oil† Philip J. Docherty, Cited by: 3.
Block copolymers as stabilizers in non-aqueous emulsion polymerization Article in Polymer International 60(11) November with 88 Reads How we measure 'reads'. The copolymer microspheres of styrene (St) and maleic anhydride (MA) were synthesized by stabilizer-free dispersion polymerization, and the polymerization process was explored in detail.
Summary: This article deals with recent progress including the authors' work concerning the application of block copolymers as polymeric surfactants in heterophase polymerizations. The synthesis methods for preparing block copolymers by emulsion and dispersion techniques are outlined, with emphasis on recently developed controlled free radical polymerizations in aqueous by:.
Block copolymers prepared over a range of molecular weights and compositions were characterized by gel permeation chromatography, osmometry and silicon analysis. Such block copolymers have been used as stabilizers for non-aqueous dispersion polymerizations of styrene and methyl methacrylate in aliphatic : Graham Taylor.using block copolymer stabilizers for dispersion poly- The study of optical properties of these new materials showed that the exaltation of the fluorescence is maximal when the [email protected]
Many copolymer morphologies have been reported in the literature. 1−5 However, there have been relatively few studies of block copolymer worms, cylinders, or rods via traditional post-polymerization processing routes, such as a solvent switch in dilute solution.
2,6−13 This is presumably because such highly anisotropic morphologies Cited by: