In the last years, interest have increased about the use of hemp fibres as reinforcement in composite materials, in uses from single pieces (car parts, travel suitcases, instrument cases) to a more complex assemblies such the body of electric cars.
During processing the fibres, the equipment produces damage in the fibres causing dislocations, kink bands or micro-compressions, referring these different denominations to similar damages produced in the structure of the fibre cell wall that can be seen, in case of being severe, as deformations of the fibre bundle. These damages have implications in the performance of the fibres as well as in the composite materials where they are used as reinforcement. In the single bundle fibre level it has been observed that fibres processed industrially exhibit lower mechanical performance than laboratory-manipulated fibres, and this lower performance might be partially related with the presence of dislocations. The impact in the composite materials leads, as well, to a lower performance of the material showing a stress concentration around the dislocation which may initiate a debonding failure. Methods to quantify the damage based on image analysis have been developed using the property that dislocations can be visualized using cross-polarized light microscopy, as well as methods based on using the higher susceptibility of dislocations to be attacked chemically. Using this background, this work explores the opportunities of a FiberLab device when used to quantify the dislocations in hemp fibres produced industrially, measuring the segments of a fibre previously acid hydrolysed and comparing the results with the quantification made with microscope. FiberLab is a fibre analyser device which is used to analyse the fibre characteristics in wood pulp fibres in the papermaking field, and it is a fast method and feasible to be implemented industrially.
Keywords: hemp, dislocations, acid hydrolysis, FiberLab, composites
Authors
Hernandez-Estrada A.
Department of Forest Products Technology, Aalto University School of Chemical Technology, Aalto, Finland
Hughes M.
Department of Forest Products Technology, Aalto University School of Chemical Technology, Aalto, Finland
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