This work is an attempt to study the effect of different latex types containing various auxiliary monomers and emulsifiers on their pigmentation and their corresponding behavior on scrub resistance. The auxiliary monomers investigated were acrylic acid (AA), methacrylic acid (MAA), and itaconic acid and the emulsifiers contained sodium lauryl sulfate (SLS) and sodium dodecylbenzene sulfonate (SDBS). It was shown that a semibatch polymerization technique which led to smaller particles and sharper size distributions is preferable. The best wet scrub results were obtained by using MAA and SLS. It was also shown that the proper selection of an auxiliary monomer generally depended on the range of incorporated pigment volume concentration (PVC). At high PVCs, AA gave better performances compared with MMA. The reverse effect was shown to occur at low PVCs.
A novel fluorescent coloured copolymer based on naphthalimide was prepared. Acenaphthene was brominated and oxidised to prepare 4-bromo-1,8-naphthalic anhydride and further reacted with butanethiol, 2-aminoethanol and acryloyl chloride, in order to obtain a new polymerisable fluorescent dye. The synthesised dyes were characterised by differential scanning calorimetry, absorption spectroscopy (Fourier Transform-infrared, proton and carbon nuclear magnetic resonance, ultravioletvisible spectroscopy) and fluorimetry. Molar extinction coefficients and wavelength maxima were obtained by examining the dye solution in ethanol. The solvatochromic effects of the prepared dyes have also been investigated. Finally, the dye was copolymerised with methyl methacrylate and an intrinsically coloured copolymer was obtained. The photophysical characteristics of the obtained copolymer have also been considered. It is assumed that 99% of the copolymerised dye is chemically bonded to polymer chains. The fluorescent characteristics of the copolymer in the solid state were determined by fluorometer and it was found that it has relatively high fluorescent intensity. The physical properties of the synthesised copolymer have been evaluated by differential scanning calorimetry and gel permeation chromatography.
The pigment loading capacity (PLC) of dispersion binders is an important factor in the formulation of a latex paint. However, there has been no reliable method for the quantitative evaluation of this property; this has led to difficulty in comparing latex binders in this regard. In this article, a new parameter, the latex dispersability index (LDI), is proposed as a quantitative measure of PLC of latex binders. In this test method, the capability of latex to disperse pigments (or extenders) is quantified on the basis of the idea of the minimum viscosity method for dispersants. The face-centered cube experimental design was used to synthesize 26 binders. On the basis of this design, the synthesized latexes had a maximum diversity of properties, especially with regard to PLC. The binders were formulated with three mineral powders (i.e., TiO 2 , CaCO 3 , and talc). The curves of viscosity versus mass of the resin for all of the samples were prepared. The general trend of the curves was universal and only depended on the nature of the powders. The geometry of the curves and PLC had quantitative correlations. To make a quantitative correlation between the curves and PLC, LDI was defined as a function of the area under the curve, the height of the curve, and the length of the end point. Four ranges of LDI were assigned to the conventional quantitative phrases for PLC. The usefulness of this parameter was then verified by some well-known commercial binders with different PLCs. The results were in a good agreement with the expected behaviors.
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