Plastics, burning mechanism degradation

Resins heated above or will rapidly lose dimensional and mechanical integrity. The poor thermal conductivity of most resins (typically 0.1-0.2Wm K ) and consequently of most reinforced plastics means that under high radiant heat, high surface temperatures are soon reached and degradation becomes rapid. As we have seen, most organic resins will rapidly degrade with the evolution of volatiles at temperatures typically between 300-400°C. These compounds, typically hydrocarbons or oxyhydrocarbons, burn readily in air. 

In the last two decades, RH and the products of its thermal degradation are often used as fillers in paper, paint [5], polymers [42, 43], polymeric composites [44 7], mbber [48-50], cement [51, 52], adhesives, and fertilizers [5]. By the addition of fillers, the mechanical, thermal, chemical, and other properties of the material are improved. Controlled burning of RH in air or inert atmosphere yields two grades of fillers, namely white rice husk ash (WRHA) and black rice husk ash (BRHA). Both these RHA have been used as fillers in polyethylene [53-55], polypropylene [56-61], polystyrene [62, 63], etc. [64, 65]. Tremendous opportunities exist in more exhaustive research on the RHA-polymer composites, which can lead to the futuristic organic-inorganic hybrid materials with specific properties. In this respect, the aim of the present work is to describe the possibility for utilization of RRHs and the products of its thermal degradation as fillers in different polymer plastic composites. 

Thermal Stability - There are several mechanisms by which polymers degrade, an important one in fire is thermal decomposition into gaseous fragments that burn. Commodity Plastics generally start to decompose as measured by TGA at 200 to 300°C, Engineering Plastics at 300 to 400°C, and ULTEM exhibits stability above 400 C - a reluctant fuel source. 

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