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Rice Husk At The Serice Of Chemical Industry

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28.05.2008

Solid products of pyrolysis of rice husk, and cellulose and lignine educed from it can be successfully used for production of various rubber types.

Such a conclusion has been made by specialists of the Republican State Enterprise “National Center for Mineral Raw Materials Complex Recycling of Republic of Kazakhstan” with participation of their colleagues from the A.V. Topchiev Institute of Petrochemical Synthesis (Russian Academy of Sciences).

Contemporary production of rubber and other plastic materials uses filling agents, which improve properties of the material. Among others, technical carbon or carbon white (hydrated silicon o?ide) are used as filling agents for rubber. Recent years witnessed significant raise of interest to creating composite materials with filling agents made of carbonic and siliceous nanostructures. A rather promising source of raw materials for their receiving is large-tonnage waste of rice production – rice husk, which includes polysacharides, lignine, neutral and tarry matter and silicon dioxide. High-clean silicon dioxide, silicon carbide and silicon are already produced from rice husk. Now, it is time to get a nanostructural silicocarbonous material.

To make a filling agent from rice husk, the raw material is to be carbonized, i.e., the carbon content should be increased in it. When selecting optimal conditions, the researchers exposed rice husk to thermal decomposition in the temperature interval of 450 to 1,000ºC at the heating rate of 15 to 20ºC per minute in the atmosphere of outlet gases, controlling the output and content of obtained solid products. As temperature increases, the silicocarbonous material output decreases, the organic carbon content remains practically constant, and the silicon dioxide content rises. Tests have shown that it is better to process rice husk at the temperature of 650ºC. Under these conditions, nanodimensional particles of amorphous carbon and silicon dioxide are received, which are easily distributed in the caoutchouc matrix and improve rubber compound’s processing characteristics, including durability and plasticity. Tire rubber and general mechanical rubber goods with application of carbonizers from rice husk and its derivatives as a filling agent exceed by quality analogous products manufactured with technical carbon or carbon white. Besides, new silicocarbonous filling agents (due to higher content of hydrocarbon phases) enable to reduce plasticizer consumption or to do without it at all.

The obtained results allow to consider carbonizers from rice husk and its derivatives as promising nanostructural filling agents for elastomers.

Olga Myznikova | Source: alphagalileo
Further information: www.informnauka.ru

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