Inorganic Agents

Inorganic blowing agents are used mainly in rubber technology [8]. They have limited application in the plastics technology. Here are some examples of the most currently used ones and their decomposition mechanism  

Sodium Hydrogen Carbonate. Sodium hydrogen carbonate decomposes when heated according to 

Ammonium Hydrogen Carbonate. Ammonium hydrogen carbonate begins to decompose at 65 C in the following way  

Sodium Nitrate and Ammonium Chloride Mixture. Since CO2 diffuses very easily out of vulcanized rubber products, this mixture can be used advantageously in those cases. The decomposition reaction proceeds in the two following steps  

NaN02 + NH4CI NH4NO2 + NaCl NH4NO2 2H2O -I- N2 

Takano et al. (2002) determined the cytotoxicity of heavy metals by measuring the lactate dehydrogenase release and Cr release from lysed rat alveolar 

Inhalation of cadmium oxide smoke in man has been known to produce progressive emphysema (Lane and Campbell 1954), a condition which, as Macklin (1954) has pointed out, would be expected to follow from localised defects in the lung lining. 

Exposure of the human cell line A549 to 1-10 liM CdCb triggered a slight accumulation of glutathione, whereas this compound was depleted after exposure to concentrations of 25-100/tM of cadmium (Gaubin et al. 2000). treatment of cells with 20 or 40 mM W-acetyl-L-cysteine, which traps free radicals, was found to increase by 30 % the glutathione level and to suppress the overexpression of stress proteins. 

Isolated rat type II lung cells were more sensitive than Clara cells to cadmium-induced apoptosis and cell viability (LIg et al. 2002). On exposure to 10 jUmol/1 cadmium acetate, the levels of the apoptosis-modulating proteins p53 and Bax were increased at 2 h and 5-12 h, respectively. The expression of p53 preceded the expression of Bax and the apoptotic process. The exposure to 10/ nol/l cadmium acetate did not significantly increase the formation of cellular reactive oxygen species. However, after the exposure to a high concentration of cadmium acetate (100/anol/1), a 30% increase of the reactive oxygen species level was observed. Catalase, superoxide dismutase, dimethyl sulphoxide, or tetramethylthiourea did not protect against cadmium-induced apoptosis. 

Exposure of an immortalised rat type II alveolar epithelial cell line to 10 fM CdClj for 24 h caused a significant decrease in viability (Timblin et al. 1998). After 48 h of exposure to 1,5, or 10 /iM CdCU a dose-dependent decrease in viability was observed at dl concentrations as determined by trypan blue exclusion and cell counting. Significant increases in reduced and oxidised glutathione levels were observed at 24 and 48 h in rat lung epithelial cells exposed to CdC. Hart et al. (1999) observed a maximum level of apoptosis (5-fold higher than control) in cultures exposed for 48 h to 20/ M 

---

Tolerance in insects to increasing amounts of DDT, BHC, and several of the inorganic agents, such as arsenic, is known to occur. However, in animals, this phenomenon has not been demonstrated to the same degree. Ability of the cells of insects to function in the environment of a toxic agent, without alteration of cellular function, is one of the most striking of biologic phenomena. 

Organic chemicals (alcohol, tars, dyes, solvents.. . ) Inorganic agents (metals - arsenic, nickel.. . ) Hormones... 

Polon JA. The mechanisms of thickening by inorganic agents. J Soc Cosmet Chem 1970 21 347—363. 

AJ Michell. FTIR Spectroscopic Studies of the Reactions of Wood and of Lignin Model Compounds with Inorganic Agents. Wood Sci. Tech. 27 69-80, 1993. 

Gilson 1992 Organic and inorganic agents in molecular sieve synthesis [20J... 

Bates B (1998). Heavy metals and inorganic agents. In Clinical Management of Poisoning and Drug Overdose, Vol. 55, pp. 750-756. 

ORGANIC AND INORGANIC AGENTS IN THE SYNTHESIS OF MOLECULAR SIEVES... 

The role of organic and inorganic agents is therefore multifarious but can be summarized as follows ... 

---