Latex Characterisation

The characterisation of latex particles (i.e., the quantification of the latex properties) (153), is necessary to distinguish one latex from another. The fundamental latex properties discussed below are directly related to the latex performance in its intended application (245). By knowing the factors that cause one latex to perform better than the others, the latex formulation and processing can be optimised. 

The desired reactor temperature (270,271) is a balance between the heating time, the propagation rate constant, the initiator dissociation constant, and the heat removal capabilities of the reactor. Polymerisations are usually 

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The polymerisation of vinyl acetate in microemulsions stabilised with cetyltrimethylammonium bromide surfactant was investigated as a function of concentrations of monomer and initiator and temperature. Molar mass distributions, phase behaviour and latex characterisations were analysed. 44 refs. 

This paper is the seventh in a series discussing colloid chemistry, and focuses on latex paints. These are defined, and then discussed under the following headings terminology, general features, inherent contradictions, emulsion paints as latex-based compositions, latex characterisation, colloid characteristics, latex modification, latex stability, latex paints as polymers and pigment mixed dispersions, functional additives, and paint stability. 5 refs. 

E. Daniels, E. D. Sudol, and M. S. El-Aasser, eds.. Polymer Latexes Preparation, Characterisation and Applications, ACS Symposium Series, Vol. 492, American Chemical Society, Washington, D.C., 1992. 

The useful range of the transmission electron microscope for particle size measurement is c. 1 nm-5 p,m diameter. Owing to the complexity of calculating the degree of magnification directly, this is usually determined by calibration using characterised polystyrene latex particles or a diffraction grating. 

U. Buranov Anvar and B.J. Elmuradov, Extraction and characterisation of latex and natural rubber from rubber bearing plants, /. Agric. Food Chem. 58(2), 2010 (www.ncbi.nlm.nih.gov). 

Poly (vinyl alcohol-co-vinyl acetate) polymers are surface active species which can be used to stabilise latex and oil in water dispersions. In order to understand the properties of these materials, it is necessary that their sequence distributions are well characterised. A number of NMR studies on the microstructure of PVA/PVAc copolymers have been made [51-53] (see also chapter 3). Moritani and Fujiwara [51], for example, have used proton and carbon-13 NMR spectroscopy to extract dyad distributions for a range of copolymers with different degrees of deacetylation. Samples were prepared using one of three routes direct saponification of PVAc alcoholyis of PVAc using sodium methoxide and reacetylation of PVA. From the polymer composition and the dyad distribution, the parameter rj was calculated for each polymer as follows ... 

Frankema, W. van Bmijnsvoort, M. Tijssen, R. Kok, W.T. Characterisation of core-shell latexes by flow field-flow fractionation with multi-angle tight scattering detection. J. Chromatogr. A, 2002, 943, 251-261. 

This article will provide a general overview of the emulsion polymerisation process and explain how the resulting latexes are used in industrial applications. An introduction to the basic concepts of emulsion polymers will be given, followed by a description of the various production processes and characterisation methods. The classes of emulsion polymers will be surveyed, and the commercial technologies and potential future uses discussed. A number of comprehensive texts on emulsion polymers are available for more in-depth study (60, 89, 94,95, 364, a.l-a.ll). 

Journal of Applied Polymer Science 84, No.8,23rd May 2002, p. 1620-8 SYNTHESIS AND CHARACTERISATION OF URETHANE/ACRYLATE COMPOSITE LATEX I.imin Wu Bo You Dan Li Fudan,University... 

Aniline was added to a monodisperse cationic polystyrene latex and polymerisation initiated by the addition of ammonium persulphate solution, forming a core-shell latex, which was characterised by infrared spectroscopy, and scanning and transmission electron microscopy. The composites exhibited electrical conductivity comparable to that of pure polyaniline, with a percolation threshold of approximately 3 wt% polyaniline. 12 refs. 

Orlando, EL., Fall 1996, p.101-102. CHARACTERISATION OF SEMIBATCH PBA LATEX PARTICLES STABILIZED BY A POLYMERIZABLE SURFACTANT Chen Y C Chem C S Taiwan,National Institute of Technology... 

The objective of this work was to characterise the sodium dodecyl allyl sulphosuccinate (Eliminol JS-2) stabilised poly(butyl acrylate) (PBA) lattices produced in a semibatch reactor. The PBA latex particles were prepared using a semibatch pulsion polymerisation process. It was found that the concentration of JS-2 or sodium dodecyl sulphate present in the initial reactor charge is very important in determining the final latex particle size. The higher the particle size polarity is, the larger is the saturated particle surface area covered by one JS-2 molecule. It was also found that at a common surfactant concentration, the JS-2 stabilised latex displays reduced chemical stability than the sodium dodecyl sulphate stabilised latex. The results of such research should be useful to tape and label manufacturers. 3 refs. 

The application of the miniemulsion polymerisation technique to the encapsulation of titanium dioxide inside PS latex particles was investigated. The dispersions were prepared by sonication of the titanium dioxide in the presence of polybutene-succinimide pentamine stabiliser. Latexes were characterised in terms of the encapsulation efficiencies and particle size. 36 refs. 

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