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Western red cedar panels, one coated with a soft latex-based acrylic polymer clear coating and the other uncoated, were exposed outdoors under a series of cut-off filters for 50 weeks. FTIR-ATR spectra of the panels showed that the extent of delignification increased with decreasing wavelengths of the solar radiation incident at the wood surface. The results support the proposal that it is the UV component of sunlight that is primarily responsible for the degradation of lignin. The extent of loss of lignin from the surface of the exposed coated panel was significantly less than that for the exposed uncoated panel suggesting that the coating confers some protection from weathering to the underlying timber. Colorimetric measurements also showed that the degree of discoloration of the panels is related to the wavelength of the radiation penetrating the wood surface.

The physical chemistry involved in the invention and development of a novel aqueous composite polymer latex technology at Dulux Australia is described. The polymerization process employed leads to a latex wherein each particle contains a blend of two or more copolymers. These particles are sterically stabilized by a new class of non-ionic reactive surfactant which results in excellent colloidal stability. A paint based on this technology has been commercialized in the coil coating industry. The particle size distribution of the latex used in this paint is studied before, during and after polymerization. The evidence obtained confirms that the desired composite polymer particles are formed by a suspension polymerization mechanism and that little or no polymer separation due to secondary nucleation (nucleation of polymer particles from the aqueous phase) takes place.

As we celebrate the 250th anniversary of this birth, Bernard Leary looks at the founder of homeopathy's career. [ABSTRACT FROM AUTHOR]