Burning resistance

While it is conceivable that an excess of bases in the cell solution might be protective against mild sulfur burn, this possibility has not yet been tested. On the other hand, a small increase in buffer capacity might reduce sulfur burn. An example of this effect may be seen in the buffer curves of the leaf sap in two of the United States Department of Agriculture s muskmelon varieties. No. 5, which is susceptible to sulfur burn, has a buffer curve which lies 0.2 to 0.3 pH unit closer to the acid side than the buffer curve of the sulfur burn-resistant variety, No. 11353 (Figure 1). 

Figure 1. Titration Curves of Leaf Tissue Fluids of Sulfur Burn-Susceptible and Sulfur Burn-Resistant Muskmelon Leaves...

A Japanese patent describes the treatment of metal surfaces with amorphous layers of second metals having a thickness of 0.2-2.5 pm. The metal component includes one, or more, of the following V, Nb, Ta, N, P, As, Sb, Bi, Cr, Mo, W, S, Se, Te, and Po. The introdnction of snch a snrface coating is claimed to improve wear and burning resistance of the metal. Also, the coating serves to increase the retention of oil films by the metal surface thus improving lubrication properties. 

Noryl phenylene ether-based resins are relatively resistant to burning, and their burn resistance can be increased by judicious compounding. They may be modified with glass and other mineral fillers. Because of low moisture absorption, dimensional stability, and ability to be used over a wide temperature range, Noryl phenylene ether-based resins are especially adaptable to metallizing. However, like most amorphous polymers, they show poor solvent resistance. 

Place the candle on a burn-resistant surface, such as a lab table. Carefully strike a match and light the candle. Use a stopwatch or a clock with a second hand to measure the time. Allow the candle to burn for 5 min. Then, blow out the flame. Record your observations. 

For cigarette burn resistance test, a lit cigarette is placed horizontally on the coating surface for 1 min. The tested area is cleaned with water and suitable solvent and then examined for change in surface appearance or visible aspects of coating. 

Figure 5.59 Schematic of an RP composite S-2 glass fiber/burn resistant phenolic adhesive prepreg and aluminum metal lay-up (adhesive by Cytee, formerly American Cyanamid, Havre de Grace, MD) includes use on the Airbus A380 fuselage providing directional properties...

Flammability Classification This classification system defines the level of ignition and burning resistance of a specimen. 

Diamond is very resistant to chemical reagents potassium dichromate and sulphuric acid attack it with the formation of CO2. It burns in air or oxygen at 700 C to CO2 leaving scarcely any ash some forms of bort may leave as much as 4-5% ash. 

Titanium, when pure, is a lustrous, white metal. It has a low density, good strength, is easily fabricated, and has excellent corrosion resistance. It is ductile only when it is free of oxygen. The metal, which burns in air, is the only element that burns in nitrogen. 

The weight and constmction of the fabric affect its burning rate and ease of ignition. Lightweight, loose-weave fabrics bum much faster than heavier weight fabrics therefore, a higher weight add-on of fire retardant is needed to impart adequate flame resistance. 

Nondurable Finishes. Flame-retardant finishes that are not durable to launderiag and bleaching are, ia general, relatively iaexpensive and efficient (23). In some cases, a mixture of two or more salts is more effective than either of the components alone. For example, an add-on of 60% borax (sodium tetraborate) is required to prevent fabric from burning, and boric acid is iaeffective as a flame retardant even at levels equal to the weight of the fabric. However, a mixture of seven parts borax and three parts boric acid imparts flame resistance to a fabric with as Utde as 6.5% add-on. 

Cotton—Wool Blends. Although they command only a very small fraction of the cotton blend market, cotton—wool blends are easier to make fire resistant than cotton itself. As might be expected, twiU fabrics containing both cotton and wool had decreased burning rates and increased 01 values both before and after fire-retardant treatment (147). 

Dead-burned magnesia, characterized by large crystaUite size and very low chemical reactivity, is resistant to the basic slags employed in the metals refining industry. It reacts very slowly with strong acids, and does not readily hydrate or react with carbon dioxide unless finely pulverized. 

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