Assessing the susceptibility of hemp fibre to the formation of dislocations during processing

•Explored Bauer McNett fibre classifier to assess the impact of processing in the formation of dislocations in hemp fibres.•Related the segmentation after fractionation in Bauer McNett with the processing of the fibres.•First processing (decorticator) has the highest impact in inducing dislocations.•Further coarse separation and carding has lower impact, but add more dislocation-like damage.

A method to assess the impact of processing on hemp fibres is presented. A testing process based on acid hydrolysis followed by fractionation, employing a Bauer McNett apparatus, was used to assess the extent to which dislocations formed in hemp fibre that had undergone different degrees of mechanical processing. Using the potential of acid hydrolysis to break the fibres preferentially at dislocations, fractionation was used to classify the resulting segments by size into eight fractions. Overall, the assessment method was shown to be a feasible and robust, as well as a reasonably fast technique. Using the same method, samples of hemp fibre taken from different stages of the production chain were used to assess the impact of the production processes on the formation of dislocations in the fibres. The results show that the first stage of processing (decortication) has the greatest impact on the formation of dislocations and that further processing steps (carding or coarse separation) also add more dislocations but with a lower impact.