Resins, combustible

Resins, Combustible. Compds corresponding to the formula RCX2N02 (where R denotes H, alkyl, aryl or alkylol, and X stands for H or -CH2OH). Prepn involves 1 to 3 moles of an aliphatic aldehyde, preferably formaldehyde, in an alkaline, neutral or acid medium. Typically,... 

Properties Yellow-brown fused mass, relatively light stable. Mp 86C, bp 350C. Soluble in alcohol, esters, ketones, aromatic hydrocarbons, and vegetable oils insoluble in water. Compatible with a wide variety of resins including most of the cellulosic and vinyl resins. Combustible. 

Properties Colorless, viscous liquid. Bp 227-234C (4.5 mm Hg), fp -60C, refr index 1.480 (20C), d 0.965 (25C), flash p 395F (201C). Insoluble in water compatible with vinyl chloride resins and some cellulosic resins. Combustible. 

Properties Somewhat viscous liquid. Bp 143C (2.5 mm Hg), fp approximately -72C, d 1.170 (25/4C), flash p 347F (175C). Miscible with water, alcohol, and glycerol. Compatible with polyvinyl alcohol, many cellulosic and natural resins. Combustible. 

Properties Straw-yellow liquid. D 1.21 (25C), bp 172C (0.8 mm Hg),refr index 1.541 (25C), viscosity 500 cP (25C), flash p 350F (176C) (COC). Miscible with most organic resins. Combustible. 

Fire resistance of FRP composites is also of concern in aerospace applications a review [120] found severe degradation in postfire flexural properties for FRP epoxy composites which were induced by delamination formation due to resin combustion. 

It has good weathering resistance and does not support combustion. It is resistant to most chemicals and solvents and has greater strength, wear resistance, and creep resistance than the preceding three fluorocarbon resins. 

If a waste sulfuric acid regeneration plant is not available, eg, as part of a joint acrylate—methacrylate manufacturing complex, the preferred catalyst for esterification is a sulfonic acid type ion-exchange resin. In this case the residue from the ester reactor bleed stripper can be disposed of by combustion to recover energy value as steam. 

Two processes may be used in the manufacture of combustible cases the original post-impregnation process and the more recently and more widely employed beater additive process. The processes differ primarily in the point at which the required resin is added to the composition. A schematic of the beater additive process is shown in Figure 11. 

The amount and physical character of the char from rigid urethane foams is found to be affected by the retardant (20—23) (see Foams Urethane polymers). The presence of a phosphoms-containing flame retardant causes a rigid urethane foam to form a more coherent char, possibly serving as a physical barrier to the combustion process. There is evidence that a substantial fraction of the phosphoms may be retained in the char. Chars from phenohc resins (qv) were shown to be much better barriers to pyrolysate vapors and air when ammonium phosphate was present in the original resin (24). This barrier action may at least partly explain the inhibition of glowing combustion of char by phosphoms compounds. 

Because PTFE resins decompose slowly, they may be heated to a high temperature. The toxicity of the pyrolysis products warrants care where exposure of personnel is likely to occur (120). Above 230°C decomposition rates become measurable (0.0001% per hour). Small amounts of toxic perfiuoroisobutylene have been isolated at 400°C and above free fluorine has never been found. Above 690°C the decomposition products bum but do not support combustion if the heat is removed. Combustion products consist primarily of carbon dioxide, carbon tetrafluoride, and small quantities of toxic and corrosive hydrogen fluoride. The PTFE resins are nonflammable and do not propagate flame. 

Low Level Waste Treatment. Methods of treatment for radioactive wastes produced in a nuclear power plant include (/) evaporation (qv) of cooling water to yield radioactive sludges, (2) filtration (qv) using ion-exchange (qv) resins, (J) incineration with the release of combustion gases through filters while retaining the radioactively contaminated ashes (see Incinerators), (4) compaction by presses, and (5) solidification in cement (qv) or asphalt (qv) within metal containers. 

In particular, PB and PMP are inert materials and usually present no health hazard. PMP is employed extensively for a number of medical and food packaging appHcations. Several grades conform to FDA regulations and to the health standards of other countries. Flammability of polyolefin resins is equal to that of PP, around 2.5 cm /min (ASTM D635). However, during combustion or pyrolysis, smoke, fumes, and toxic decomposition products are formed and can pose a health hazard. 

Both urea— and melamine—formaldehyde resins are of low toxicity. In the uncured state, the amino resin contains some free formaldehyde that could be objectionable. However, uncured resins have a very unpleasant taste that would discourage ingestion of more than trace amounts. The molded plastic, or the cured resin on textiles or paper may be considered nontoxic. Combustion or thermal decomposition of the cured resins can evolve toxic gases, such as formaldehyde, hydrogen cyanide, and oxides of nitrogen. 

One possible solution to the problem is to make greater use of intumescent materials which when heated swell up and screen the combustible material from fire and oxygen. Another approach is to try to develop polymers like the phenolic resins that on burning yield a hard ablative char which also functions by shielding the underlying combustible material. 

The only other glycol that is fairly common is propylene glycol which has a molecular formula of C3H (OH)2. It is a combustible liquid with a flash point of 210°F, and its major use is in organic synthesis, particularly of polyester resins and cellophane. 

The fire department blamed the accident on welders cutting in hazardous areas without a fire watch, highly combustible structural components (fiber-glass-resin), high-density storage of highly flammable and detonable material, spilled ammonium perchlorate about the plant, and high w ind conditions. 

Pittius Explosives. C. vanPittius of Holland obtd a BritP in 1910 on expls consisting of combustible mats and oxidizers. The combustible constituent is prepd by mixing resin (lOp) and stearin (5p) together at 150°, and incorporating paraffin (lOp) and a blend consisting of TNT (25p) and NG (5p) or NC (3p). Molten TNT (50p) is then added and blended while maint the mixt at 85°. The reddish-brnmixt is termed TNT paste . To use this expl the TNT paste is mixed with oxidizers, viz, a) TNT paste 20, K nitrate 30, amm perchlorate 30 and K perchlorate 20% b) TNT paste 8 and amm nitrate 92%... 

A number of other monomers may be employed as variations on the materials mentioned so far, to introduce specific properties into the finished resin. For example, halogenated molecules containing either chlorine or bromine atoms may be used to confer fire resistance. As described in Chapter 8, the effect of halogens in the polymer structure is to make the resins difficult to ignite and unable to sustain combustion. 

There are two main varieties of carbon (i) crystalline (e.g., graphite and diamond), and (ii) amorphous. The amorphous variety consists of carbon blacks and charcoals. Carbon blacks are nonporous fine particles of carbon produced by the combustion of gaseous or liquid carbonaceous material (e.g., natural gas, acetylene, oils, resins, tar, etc.) in a limited supply of air. Charcoals are produced by the carbonization of solid carbonaceous material such as coal, wood, nut shells, sugar, synthetic resins, etc. at about 600 °C in the absence of air. The products thus formed have a low porosity, but when activated by air, chlorine, or steam, a highly porous material is produced this porous product is called activated charcoal. Chemically speaking carbon blacks and charcoals are similar, the difference being only in physical aspects. Carbon blacks find use in the rubber industry and in ink manufacture. An important use of charcoals is as adsorbents. 

The chloride ion is one of the most frequently analysed by IC, e.g. following up combustion of polymers [854,855] similar analyses were reported for the bromide ion [854,855] and nitrite [855]. Analysis of polyester resins for halogens or phosphorous components may be carried out via conversion to halides and phosphates, respectively. 

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