TG curve of pure cotton fabric (Fig. 2) demonstrates three stages: in the initial stage, where the temperature range is below 300°C, the most important changes are in some physical properties and little mass loss.
Here, the damage to the cellulose occurs mostly in the amorphous region of the polymer.
However the main pyrolysis stage occurs in the temperature range of 300–370°C. In this stage, the mass loss is very fast and significant. In fact most of pyrolysis products of cellulose are formed at this stage.
According to the scientific literature [28], glucose is one of the major products generated, together with all kinds of combustible volatile gases. At 370°C the pyrolysis of char happens.
Above this temperature dehydration and charring reactions continues more obviously.
So the mass decomposition dehydration and probably decarboxylization could be obtained, and more water, carbon dioxide and other residues could be released.
Hence the enrichment of carbon content during the formation of char in the decomposed products is the resultant.
In overall it may be rationalized that: the pyrolysis of cellulose will start from its amorphous regions and continues to crystalline regions.
However it seems that the exact temperature ranges of pyrolysis may vary depending on different cellulosic materials
and various experimental circumstances [28].