Estimation of Particle Dimension and Particle Size Distribution (PSD) of Ground Leather using a Digital Image Processing Method (DIP) Rosario Mascolo, Felicia Vietri, Luca Giorleo and Alfonso Martone

Abstract

In the tanning industry, the use of solid waste as a polymer filler/ reinforcement to produce new circular materials is widespread. For example, leather fiber boards have already been on the market for some time, which are sheets for upholstery use consisting in shaving powder (generally chrome-tanned) incorporated in a polymeric matter. To respond to the need for circular and sustainable processes, numerous studies on composites with polymeric matrix filled with particulate reinforcement or tanned leather fibers have been carried out. These studies focus mainly on the characterization of the mechanical properties of the final product containing different concentrations of the filler. In literature, only in a few cases has the Particle Size Distribution (PSD) of fibers/particles (namely the dimensional distribution curve of the size of the particulate) been characterized. The dimensional quantification has always been performed on linear measurements using a microscope, but, considering a filler of milled leather fibers, linear measurements are not adequate for the characterization of the PSD, because the milling process of leather does not produce linear fibers, but agglomerates of different densities also linked by fibrous elements. The PSD analysis using a Digital Image Processing Method (DIP) on three ground samples at different sieves (4.0, 1.5 and 0.5) showed that the use of the thinner mesh led to a uniform particulate (7k square microns) but with a lower aspect ratio while a sieve of 1.5 mm allows a uniform distribution combined with slender particulates.