Natural fibers thermal decomposition

Important in combustion is not so much the thermal stability of the material itself but rather the amount and nature of the decomposition products. It is sufficient to compare the LOI of poly(vinyl chloride), whose thermal decomposition begins at 160-175 °C with that of heat resistant phenol-formaldehyde fibers (Kynol). The thermodynamic approach to the problem seems to be most reasonable. It allows to consider the polymer structure to explain the details of the combustion reactions and to estimate the heat of combustion of polymers. 

WF decompose, both materials emit oxide gases and radicals, which initiate the degradation of PLA to break down the chain. PLA blended with WF is more resistant to decomposition due to the complex lignin structure, which acts as a hydrophobic shield protecting the PLA chains from direct attack of the volatiles. This observation can be further justified by the work of Tao et al. (2009) who compared PLA blended with jute and ramie fibers they found that there was a lack of significant difference in thermal decomposition for both natural fibers (see Figure 3.13). 

It was observed that the weight losses about 310-320°C and near 380°C were ascribed to the thermal decomposition of hemicellulose and a-cellulose, respectively. The TGA result indicated that the hemicellulose component of natural fiber was not removed by silane treatment, unlike in alkali treatment [18]. 

Thermal Decomposition of Natural Fibers Kinetics and Degradation Mechanisms... 

Thermal properties of thermoplastic starch composites reinforced with pehuen husk showed the potential of this bioliber as an excellent reinforcement for composite materials. TPS composites showed a good interaction between the fibers and the plasticized starch matrix due to the natural affinity between husk and starch in the pehuen seed. TPS/PLA/PV A blend showed partial miscibility or co-continuous phase and TPS/PLA/PV A composites presented also discontinuities at the biofiber-polymeric matrix interface. The incorporation of biofiber improved the thermal stability of the composites, increasing the initial decomposition temperature. The biofiber hinders the out-dififusion of the volatile molecules (e.g., glycerol), retarding the decomposition process of starch composites. On the other hand, the degree of crystallinity of composites decreases when pehuen husk content increases (Castano et al. 2012). 

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