RESUMO
A combined study of crystallinity index (CI), degree of polymerisation (DP) and thermal stability of cellulose was carried out for monitoring the effect of ball-milling. DP and CI are two fundamental quantities that describe the physico-chemical behaviour of cellulose. Milling is a common strategy to reduce cellulose crystallinity. In this work, four different commercially available celluloses were milled at 30, 60 and 120â¯min, and the changes in DP and CI were monitored using spectroscopic, diffraction and chromatographic techniques. Evolved gas analysis-mass spectrometry (EGA-MS) was also used to evaluate the changes in apparent activation energy (Ea) of the pyrolysis reaction upon different milling times by using model-free isoconversional methods. The results showed substantial decrease in CI values and moderate changes in DP after two-hours of ball-milling. Ea were found in the range 110-140â¯kJ/mol, and were reduced by 10% on average after two hours of ball-milling.
