Thermo-Mechanical and Morphological Properties of Polymer Composites Reinforced by Natural Fibers Derived from Wet Blue Leather Wastes: A Comparative Study

Abstract

The present work investigated the possibility to use wet blue (WB) leather wastes as natural reinforcing fibers within different polymer matrices. After their preparation and characterization, WB fibers were melt-mixed at 10 wt.% with poly(lactic acid) (PLA), polyamide 12 (PA12), thermoplastic elastomer (TPE), and thermoplastic polyurethane (TPU), and the obtained samples were subjected to rheological, thermal, thermo-mechanical, and viscoelastic analyses. In parallel, morphological properties such as fiber distribution and dispersion, fiber–matrix adhesion, and fiber exfoliation phenomena were analyzed through a scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS) to evaluate the relationship between the compounding process, mechanical responses, and morphological parameters. The PLA-based composite exhibited the best results since the Young modulus (+18%), tensile strength (+1.5%), impact (+10%), and creep (+5%) resistance were simultaneously enhanced by the addition of WB fibers, which were well dispersed and distributed in and significantly branched and interlocked with the polymer matrix. PA12- and TPU-based formulations showed a positive behavior (around +47% of the Young modulus and +40% of creep resistance) even if the not-optimal fiber–matrix adhesion and/or the poor de-fibration of WB slightly lowered the tensile strength and elongation at break. Finally, the TPE-based sample exhibited the worst performance because of the poor affinity between hydrophilic WB fibers and the hydrophobic polymer matrix.

A Study of the Flexural Properties of PA12/Clay Nanocomposites

“…In previous works, the influence of the mixing parameters used on polyamide nanocomposites has been investigated, but only on tensile or thermal properties and with different reinforced particles (forming natural particles and fibers into carbon nanotubes) [ 6 , 26 , 27 , 28 , 29 ].…”

Leather-like composite materials prepared from natural rubber and two leather wastes: Wet blue leather and finished leather

“…[1][2][3][4] Nevertheless, the leather industry has been considered as one of the highly polluting industries owing to the large amounts of solid, liquid, and gaseous wastes generated at various production steps, particularly the tanning step, causing severe environmental damages to soil, rivers, groundwater, and atmosphere. [1][2][3][4][5][6][7][8][9][10][11] As a consequence, sustainable technologies have been developed in order to minimize the leather solid wastes by recovering and recycling instead of disposal to landfills owing to an increasing concern about the control of environmental pollution especially from industrial activities. [1][2][3][4]6,8 Tanning is an important process that stabilizes the proteins, particularly collagen, of the raw hides and skins.…”

“…[1][2][3][4][5][6][7][8][9][10][11] As a consequence, sustainable technologies have been developed in order to minimize the leather solid wastes by recovering and recycling instead of disposal to landfills owing to an increasing concern about the control of environmental pollution especially from industrial activities. [1][2][3][4]6,8 Tanning is an important process that stabilizes the proteins, particularly collagen, of the raw hides and skins. 2,3,12 The tanned leather is no longer susceptible to putrefaction or rotting and is then suitable for a wide variety of utilizations.…”

“…1,7,11,13 Generally, chromium in Cr +6 form is much more hazardous and carcinogenic to living beings and biological systems than in Cr +3 form, because of the water insolubility and low ability to penetrate cell membranes of Cr +3 ions. 8,9,11 Besides, the finished leather (FL) scraps are also discarded as waste from the production factory, leading to environmental problem. 2,14 Several studies have investigated the incorporation of leather solid wastes as filler into various polymeric materials, such as high density polyethylene, 3 polycaprolactam, 11 poly (vinyl chloride) (PVC), 5 poly (lactic acid) (PLA), 8 polyamide 12 (PA 12), 8 thermoplastic elastomer (TPE), 8 thermoplastic polyurethane (TPU), 4,8 poly (vinyl butyral) (r-PVB), 13 acrylonitrile-butadiene rubber (NBR), 15,16 and natural rubber (NR) 1,6,7,9,10,17 to produce composite materials.…”

“…8,9,11 Besides, the finished leather (FL) scraps are also discarded as waste from the production factory, leading to environmental problem. 2,14 Several studies have investigated the incorporation of leather solid wastes as filler into various polymeric materials, such as high density polyethylene, 3 polycaprolactam, 11 poly (vinyl chloride) (PVC), 5 poly (lactic acid) (PLA), 8 polyamide 12 (PA 12), 8 thermoplastic elastomer (TPE), 8 thermoplastic polyurethane (TPU), 4,8 poly (vinyl butyral) (r-PVB), 13 acrylonitrile-butadiene rubber (NBR), 15,16 and natural rubber (NR) 1,6,7,9,10,17 to produce composite materials. Babanas et al 5 incorporated different loadings of WBL scraps (20À60 parts by weight per hundred (phr) of resin) into plasticized PVC to produce leather-like material that could be used in footwear industry.…”