Stabilizer mixtures

Pyrotechnic mixtures may also contain additional components that are added to modify the bum rate, enhance the pyrotechnic effect, or serve as a binder to maintain the homogeneity of the blended mixture and provide mechanical strength when the composition is pressed or consoHdated into a tube or other container. These additional components may also function as oxidizers or fuels in the composition, and it can be anticipated that the heat output, bum rate, and ignition sensitivity may all be affected by the addition of another component to a pyrotechnic composition. An example of an additional component is the use of a catalyst, such as iron oxide, to enhance the decomposition rate of ammonium perchlorate. Diatomaceous earth or coarse sawdust may be used to slow up the bum rate of a composition, or magnesium carbonate (an acid neutralizer) may be added to help stabilize mixtures that contain an acid-sensitive component such as potassium chlorate. Binders include such materials as dextrin (partially hydrolyzed starch), various gums, and assorted polymers such as poly(vinyl alcohol), epoxies, and polyesters. Polybutadiene mbber binders are widely used as fuels and binders in the soHd propellant industry. The production of colored flames is enhanced by the presence of chlorine atoms in the pyrotechnic flame, so chlorine donors such as poly(vinyl chloride) or chlorinated mbber are often added to color-producing compositions, where they also serve as fuels. 

Grease a semisolid or solid lubricant consisting of a stabilized mixture of mineral, fatty, or synthetic oil with soaps, metal salts, or other thickeners. 

During World War II PETN was also used, although to a lesser extent than cyclonite, since the former is more sensitive to impact and has a lower chemical stability. Mixtures of various compositions were employed according to their intended use. The most widely used mixture comprised 50% PETN and 50% TNT. This was employed in the molten state for filling hand and anti-tank grenades, and powdered and compressed, for filling detonators. 

PospfSil J (1990) Stabilizer mixtures and polyfunctional stabilizers, In Oxidation inhibition in organic materials, Vol 1, Pospfiil J and Klemchuk P (Eds), CRC Press Boca Raton, pp 173-192. 

Plasticizers perform this function if a single plasticizer solvates the dissimilar major components of a blend. Phthalate esters help to stabilize mixtures of poly(vinyl chloride) and poly(melhyl methacrylate) for example. These materials are also plasticizers for polystyrene, and stable blends of this polymer with poly(vinyl chloride) can be made by adding dioctyl phthalate to a blend of polystyrene and rigid PVC. 

V. Malatesta, P. Allegrini, and L. Crisci, Stabilizing mixture having photochromatic activity, U.S. Patent 5242640 (1991). 

Pospisil, J. Stabilizers mixtures and polyfunctional stabilizers. In Oxidation Inhibition of Organic Materials, Klemchuk, P., Pospisil, J., Eds. CRC Press Boca Raton, 1990 Vol. 1, 173-224. 

Quinoid compounds are excellent acceptors of electrons and form electron donor-acceptor (EDA) complexes as a consequence of low-lying unoccupied electronic energy levels205. The EDA complexes may be easily formed in interactions with phenolic or amine components of a stabilizing mixture, with other additives which have reactive H atoms, with RO 2 radicals, or with some metallic impurities in polymers via rr-orbital interactions. Quinones efficiently participate in oxidation of polymers by virtue of these processes. 

It is important to recognize that additives suitable for one type of resin may have detrimental effects on another and/or on their additives. Furthermore, the stabilizing systems of one polymer type may neutralize the system of another polymer. For example, to stabilize blends comprising 55-75 wt% PO, 5-25 wt% PS, 5-15 wt% PVC, and 0-10 wt% of other thermoplastics, 0.1-0.5 wt% of a stabilizer mixture was added. The mixmre comprised a sterically hindered phenol [e.g., pentaerythritol ester], and a phosphite [e.g., tris(2,4-di-tert-butyl phenyl)phosphite] at a ratio of 5 1 to 1 5. For other compositions of PCW, different stabilizers, viz., thio-propionic acid, benzophenones, oxahdes, benzotriazoles, HALS, and/or CaO may have to be used [Pauquet et al., 1994]. 

Products and Uses An emulsifier (it stabilizes mixture and keeps it uniform) in cakes, fats (rendered animal), and whipped toppings. 

Azeotrope of AK-225 with ethanol and a stabilizer Mixture of AK-225, ethanol, hydrocarbon, and stabihzers Low viscosity and low surface tension HFE-7100 with trans 1,2-dichloroethylene and ethanol (azeotrope) Low viscosity and low surface tension and increased solubility mixture of... 

Macroemulsion is thermodynamically unstable, but kinetically stabilized mixtures of two or more immiscible liquids. The size of the dispersed droplet is usually 2 to 100 pm. The macroemulsions scatter light from the droplet interface and hence appear milky white. This is due to the larger droplets as compared to the wavelength of the incident light waves. 

FF is unstable in conditions of both light and heat. It will polymerize spontaneously at 230 C and some polymerization is likely to take place at temperatures as low as 60 °C. A stabilizer mixture consisting of N-phenylsubguanidine, N-phenylthiourea and N-phenylnaphthylamine at levels of 0.001-0.1% will prevent polymerization up to 170 °C. It follows, therefore, that care needs to be taken in distilling FF away from heavy residues. This can only be done under vacuum or in a steam distillation. 

Stejskal, J., T. Sulimenko, et al. (2000). Polyaniline dispersions 10. Coloured microparticles of variable density prepared using stabilizer mixtures. Colloid Polymer Science 278(7) 654-658. 

Polymer-stabilizer mixtures were homogenized in the W 50 EH chamber of a Brabender Plasti-Corder laboratory mixer at 190 °C and 60 rpm for 10 min. After removing the material from the chamber, 6 mm thick plaques 8 x 8 cm were molded in a laboratory hot press at 200 °C for 2 min under 50 kN for deairation plus another 2 min nnder 100 kN followed by water cooling to 70 °C for ca. 15 min under 150 kN. 

Anionic surfactants (such as sodium dodecyl sulfate), cationic surfactants (such as cetyltrimethylammonium bromide) (163), and nonionic surfactants (such as the polyoxyethylenated alkylphenols) (136,338) have been used in preparing emulsions. Different types of surfactants can be used in the same recipe (377) to provide additional stability under specific conditions. For example, mixtures of anionic and nonionic surfactants are common. The anionic surfactant controls the particle nucleation stage, and the nonionic surfactant imparts additional electrolyte tolerance, mechanical shear stability (345), and freeze-thaw stability. Mixtures of anionic and cationic surfactants tend to coagulate and are to be avoided. 

Secondary hydroxyl groups Slower urethane reaction Better humidity aging stability Mixture of Ethylene and Propylene Oxide ( ) Faster oxide addition Primary and secondary hydroxyls Lower polyol viscosity Good humidity aging properties... 

The synergic action of three types of mixtures of polyvinyl chloride stabilizers mixtures of two decelerators of thermal dehydrochlorination that do not bond hydrogen chloride, mixtures of two stabilizers that are hydrogen chloride acceptors, and mixtures of hydrogen chloride acceptors with decelerators of dehydrochlorination, possessing no acceptor properties, was investigated in [54, 73, 86]. 

Regarding the mechanical properties of the stabilized mixtures, modrdus, impact strength, and elongation at break show improvements up to 25%, but their values remain low, in particular elongation at break and impact strength. 

While not often described in the scientific literature, the use of mixed silane layers is becoming of significant industrial importance. As described by Pape and Plueddemann [74] mixtures of reactive and non-coupling silanes can still give high property levels with improved hydrolytic stability. Mixtures of two different reactive silanes are also reported as being beneficial. 

MAPP Gas is a stabilized mixture of methy-lacetylene and propadiene. Alkane and alkene hydrocarbons are added as stabilizers. The stabilizers serve to render the methylacetylene and propadiene shock insensitive and to ensure that their concentrations remain nearly uniform at all times during vaporization of the mixture [1]. 

Synergetic mixtures presenting no health hazard are worthy of mention. They are zinc-based compounds mixed mainly with calcium soaps. Since zinc-containing stabilizers function only at very low concentration in PVC (0.1-0.4% by weight), it is necessary to ensure a good dispersion of the stabilizer mixture in the polymer matrix to obtain the best stabilizing effect. Too high a concentration of zinc stabilizer decreases the heat stability of PVC appreciably [55]. To avoid this, epoxide compounds should be used as HCl acceptors in conjunction with the stabilizer mixture. 

Usually the first two objectives must be concomitantly considered and fulfilled. High effectiveness cannot be obtained one-sidedly by the addition of a single additive. That is why complex systems of additives (antioxidants, light stabilizer mixtures, or complex formulations of several additives) are used. 

Transformation products of phenolic antioxidants act differently and in many cases contrary to under photo- and thermo-oxidative conditions, also influencing the efficiency of stabilizer mixtures in different ways. Phenol-HAS mixtures also behave synergetically during thermo-oxidation, but show antagonistic effects during photo-oxidation. 

Binding capacity. Lubricants are suitable binders for powdery solids, used for the production of nondusting forms of some additives. Ready-to-use lubricant/ stabilizer mixtures are delivered as flakes or fine beads. 

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