Copolymer latex particles

Duracher D, Sauzedde F, Elaissari A, Perrin A, Pichot C (1998) Cationic amino-containing A-isopropyl acrylamide-styrene copolymer latex particles 1-particle size and morphology vs. Polymerization process. Colloid Polym Sci 276(3) 219-231... 

The object of this study was to clarify some aspects of the mechanism of shear-induced flocculation in colloidal dispersions. Vinyl chloride homopolymer and copolymer latices were prepared by emulsion polymerization using sodium dodecyl sulphate as emulsifier. Agglomeration behavior in these latices was studied by measuring the mechanical stability using a high speed stirring test. The latex particle size was measured by an analytical centrifuge. Molecular areas of emulsifier in the saturated adsorption layer at the surface of homopolymer and copolymer latex particles were estimated from adsorption titration data. 

Structure in VAc copolymer latex particles has been investigated in die past and continues to be an area of intense study. General areas of investigation are inadvertent structure, such as that caused by the difference in reactivi ratios and monomer solubili differences, and intentional structure, that produced by polymerizing monomers in a controlled manner to obtain the desired structured particles. 

Fig. 9 TEM images of the polymer films formed from the polyBA232-f>-poly(BA25-co-styrene257) diblock copolymer latex particles (a) after drying at room temperature for 4 days, and (b) after solvent-casting in dichloromethane and drying at 15°C for 48 h...

No.25, 1997, p.6097-102 COLLOIDAL AND ELECTROKINETIC BEHAVIOUR OF METHYL METHACRYLATE-BUTYL ACRYLATE COPOLYMER LATEX PARTICLES... 

Methyl methacrylate-butyl acrylate copolymer latex particles were synthesised by both seeded and unseeded semicontinuous emulsion copolymerisation. Particle size and surface charge densities were characterised by TEM and potentiometric and conductimetric titrations. An investigation of the effect of surface density on zeta-potential is described. 18 refs. 

Fig. 5 TEM micrograph of the styrene/PBBA copolymer latex particles. Bar indicates 100 nm...

B. Elmas, M. A. Onur, S. Send and A. Tuned, Thermosensitive N-isopro-pylacrylamide-vinylphenyl boronic acid copolymer latex particles for nucleotide isolation. Colloids Surf., A, 2004, 232(2-3), 253-259. 

DnracherD, SanzeddeE, ElaissariA, PerrinA, PichotC. Cationic amino-containing A-isopropylacrylamide-styrene copolymer latex particles. 1. Particle size and morphology vs. polymerization process. Colloid Polym. Set 1998 276 219-231. 

Castanheira EMS, Martinho JMG, Duracher D, Charreyre MT, Elaissari A, Pichot C. Study of cationic A-isopropylacrylamide-styrene copolymer latex particles nsing fluorescent prohes. Langmuir 1999 15(20) 6712-6717. 

Ehnas B, Onur MA, Send S, Tuncel A. Thermosensitive A-isopropylcarylamide-vinylphenyl boronic acid copolymer latex particles for nucleotide isolation. Colloid Surf. A Physicochem. Eng. Aspects 2004 232 253-259. 

The emulsion polymerisation process strategy, can have a considerable effect on molecular structure and particle morphology. The intrinsic factors as well as the process conditions determine the colloidal aspects of the copolymer latex (particle diameter, surface charge density, colloidal stability etc.), the characteristics of the polymeric material in the particles and the structure of the particles (copolymer composition as a function of particle radius etc.). In turn, these factors determine the properties of the latex and the copolymer product. 

For instance, this procedure is followed in manypapers dealing with the semi-continuous emulsion copolymerisation of vinyl acetate and butyl acrylate (e.g. El-Aasser et al, 1983). Two main situations can be distinguished with respect to the monomer addition rate, (a) Flooded conditions the addition rate is higher than the polymerisation rate, (b) Starved conditions the monomers are added at a rate lower than the maximum attainable polymerisation rate (if more monomers were to be present). The latter process (starved conditions) is often applied in the preparation of homogeneous copolymers/latex particles. In this case after some time during the reaction, because of the low addition rates, a steady state is attained in which the polymerisation rate of each monomer is equal to its addition rate and a copolymer is made with a chemical composition identical to that of the monomer... 

The latex stability characteristics related to surface chemistry were analyzed by Polatajko-Lobos and Xanthopoulo [47] by studying the relationships between the concentration of surface-bound functional groups on carboxylated styrene-butadiene copolymer latex particles and the mechanical and chemical stability of the latexes synthesized. 

Zhao, J. and Brown, W. 1995. Adsorption of a nonionic surfactant (C12E7) on carboxylated styrene-butadiene copolymer latex particles. J. Colloid Interface Sci. 169 39-Al. 

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