Synthetic chars

Poly vinyl chloride Synthetic-char formers >180 >180 450 37-39... 

While neither the MWNT elongated cylinders nor the exfoliated clay sheets resulted in self-extinguishing behavior, they did slow the rate of fire spread by reducing the rate of heat evolution. Both of these nano materials form a kind of synthetic char, more effectively than larger particulate fillers, and act as heat shields. It may be that combinations of several types of materials will prove most effective in reducing fire spread. 

Od condensed from the released volatdes from the second stage is filtered and catalyticady hydrotreated at high pressure to produce a synthetic cmde od. Medium heat-content gas produced after the removal of H2S and CO2 is suitable as clean fuel. The pyrolysis gas produced, however, is insufficient to provide the fuel requirement for the total plant. Residual char, 50—60% of the feed coal, has a heating value and sulfur content about the same as feed coal, and its utilisation may thus largely dictate process utdity. 

Phosphoms compounds are effective flame retardants for oxygenated synthetic polymers such as polyurethanes and polyesters. Aryl phosphates and chloroalkyl phosphates are commonly used, although other compounds such as phosphonates are also effective. The phosphoms compounds can promote char formation, thereby inhibiting further ignition and providing an efficient thermal insulation to the underlying polymer. 

Ar CH=CHAr and ( >Ar C(Ar)=CH2, as main products (Ikenaga et al., 1986). This loss of regioselectivity disqualifies this reaction for synthetic purposes. Surprisingly, however, a-styrylstannanes (10.24, R=CH3, C2H5, n-C4H9) selectively gave the (Z)- rather than the (is)-stilbene derivatives (Scheme 10-63 Kikukawa et al., 1986). 

The carbon in coal can exist in two forms, volatile carbon and base carbon. Volatile carbon is released by pyrolysis while base carbon remains as a residual char or coke. Both forms of carbon in coal have been utilized in the development of synthetic fuel. 

Conversion of polymers and biomass to chemical intermediates and monomers by using subcritical and supercritical water as the reaction solvent is probable. Reactions of cellulose in supercritical water are rapid (< 50 ms) and proceed to 100% conversion with no char formation. This shows a remarkable increase in hydrolysis products and lower pyrolysis products when compared with reactions in subcritical water. There is a jump in the reaction rate of cellulose at the critical temperature of water. If the methods used for cellulose are applied to synthetic polymers, such as PET, nylon or others, high liquid yields can be achieved although the reactions require about 10 min for complete conversion. The reason is the heterogeneous nature of the reaction system (Arai, 1998). 

In this part, we will distinguish between natural and synthetic fibers because different methods are usually involved to provide flame retardancy by intumescence for the two classes. A few papers report recent development and performance of intumescent textiles. Very often the authors describe the mechanism of action of their materials as mechanism via charring enhancement or something similar. Nevertheless based on the chemical nature of the flame retardant used and by the described... 

Owing to the multiple combinations involving interfacial compatibilizers and char promoter agents, including various polymers, this category of FR systems appears promising and yet able to meet industrial demand based on the association of excellent FR and mechanical properties. Moreover, the emergence of synthetic anionic clays, like LDHs, offers new possible combinations. 

---