Effect of sample preparation and heating rate on the differential thermogravimetric analysis of flax fibres

Thermograms of fine, medium and coarse fibres prepared by cutting, milling and freeze-grinding at 5 degrees, 20 degrees and 50 degrees C/min heating rates were compared. Scanning electron microscopy revealed that fibre ends prepared by the three methods were distinctly different from each other and, in addition, the mean length of the fibres was lowest in cut samples. Thermal analyses at the three heating rates have shown that weight loss and peak temperature in the primary peak were higher in fine fibres and the reverse was observed in coarse fibres. Statistical analysis of the results revealed that interaction of heating rates, fibre grades and preparation methods were highly significant. This suggests that fibre characteristics including fineness may be extrapolated from the pyrolysis data obtained at a medium heating rate.