BLOOM-FREE

The reduction of rubber-sulphur ratio gives an advantage of bloom-free products in soft rubber goods. But this is an exception in the case of hard rubber or ebonite. 

Solid adducts Isolated amine products, in particular, offer advantages such as low colour, low free amine content and low irritation potential they also provide non-yellowing, bloom-free films with good chemical and solvent resistance Amine adducts solvent-based, two-pack coatings, e.g. primers, finishes and coal tar epoxy coatings... 

Ancient iron structures sometimes show no sign of corrosion or at most, very little. The clean atmosphere of past centuries may be responsible in that it allowed a very thin adherent layer of oxide to develop on the surface [22], This layer very often protects against even today s increasingly aggressive industrial pollutants Very often the conditions of the initial corrosion are the ones that determine the lifespan of metals [23], A well-known example is the sacred pillar of Kutub in Delhi, which was hand forged from large iron blooms in 410 a.d. In the pure dry air, the pillar remains free of rust traces but shows pitting corrosion of the iron... 

Although metal-free azo pigments have good chemical resistance their completely covalent nature leads to a tendency to bleed in organic solvents and to migration and blooming in... 

The environmental occurrence of the lower A9PEO oligomers in several types of sediments was studied in the Venice lagoon [2]. A distinction was made between sediments covered with a layer of macroalgae (which are blooming massively in spring-summer), and sediments free of macroalgae. 

Effects of Pentavalent Sb Ions on the Adsorption of Divalent Co-57 on Hematite. Benjamin and Bloom reported that arsenate ions enhance the adsorption of cobaltous ions on amorphous iron oxyhydroxide (J 6). Similarly, when divalent Co-57 ions were adsorbed on hematite together with pentavalent Sb ions, an increase of adsorption in the weakly acidic region was observed. For example, when 30 mg of hematite was shaken with 10 cm3 of 0.1 mol/dm3 KC1 solution at pH 5.5 containing carrier-free Co-57 and about 1 mg of pentavalent Sb ions, 95 % of Co-57 and about 30 % of Sb ions were adsorbed. The emission spectra of the divalent Co-57.ions adsorbed under these conditions are shown in Figure 8 together with the results obtained under different conditions. As seen in Figure 8, the spectra of divalent Co-57 co-adsorbed with pentavalent Sb ions are much different from those of Co-57 adsorbed alone (Figure 3). These observations show a marked effect of the.co-adsorbed pentavalent Sb ions on the chemical structure of adsorbed Co-57. 

Since 2000, the field of asymmetric catalysis has bloomed extensively (and perhaps unexpectedly) with the introduction of a variety of metal-free catalysis concepts that have collectively become known as organocatalysis. Perhaps more impressive... 

Light. Ultraviolet (uv) light promotes free-radical oxidation at the mbber surface which produces discoloration and a brittle film of oxidized mbber (35). This skin cracks in random directions to form a pattern called crazing, which can be prevented by the addition of carbon black fillers or uv stabilizers. Black stocks are more resistant to uv light than are gum or light-colored stocks. Nonblack compounds require larger quantities of nonstaining antioxidants which should bloom to the surface as the surface uv stabilizers deplete. 

Bloom s syndrome is a rare autosomal recessive disease characterized by a high level of spontaneous chromosomal aberrations and sister chromatid exchange (SCE). Bloom s syndrome involves exhibiting numerous clinical features including predisposition to cancer. The importance of oxidative stress in Bloom s syndrome follows from the overproduction of superoxide, an increase in free radical-mediated damaging processes, and SOD induction... 

The most important chain transfer antioxidants are phenols and aromatic amines (B-81MI11502). They act by donating hydrogen to the peroxy radical with the formation of a stable free radical which does not take part in further chain reactions (equation 4). Two amine antioxidants, used in the rubber industry, are 6-dodecyl-l,2-dihydro-2,2,4-trimethylquinoline (1) and polymeric l,2-dihydro-2,2,4-trimethylquinoline (2). Because of its polymeric structure (2) is thermally stable, has low volatility and is non-blooming, i.e. it shows little tendency to migrate. 

Because antiozonants and waxes, which to be effective must form a surface bloom, are used to enhance ozone resistance it is usual to condition test pieces in the strained state before exposure. The usual conditioning period is between 48 and 96h and the test pieces should be kept in the dark and in an ozone-free atmosphere. For this treatment to be effective, the test piece surface must not of course be touched in the course of subsequent handling. Where specifications wish to specifically exclude compounds which rely on an adequate wax film for protection, the conditioning period is dispensed with. Hill and Jowett47 in a criticism of ozone test methods strongly make the point that the conditioning process should be relevant to service conditions if a discriminating evaluation of waxes is to be made. 

Laanbroek, H. J., J. C. Verplanke, P. R. M. de Visscher, and R. de Vuyst. 1985. Distribution of phyto- and bacterioplankton growth and biomass parameters, dissolved inorganic nutrients and free amino acids during a spring bloom in the Oosterschelde basin, the Netherlands. Marine Ecology Progress Series 25 1-11. 

Middleboe, M., M. Sondergaard, Y. Letarte, and N. H. Borch. 1995a. Attached and free-living bacteria Production and polymer hydrolysis during a diatom bloom. Microbial Ecology 29 231-248. 

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