An innovative material based on natural rubber and leather tannery waste to be applied as antistatic flooring

Abstract

In recent decades, the production chain of beef and bovine leather has grown significantly because of an increase in the world's population and improved access to consumption. However, the generation of waste derived from this sector has grown simultaneously, and consequently, improved ways of adding value, reusing, and disposing these waste materials are being sought. In this article, we present a new and innovative composite material based on vulcanized natural rubber (NR), carbon black (CB), and leather waste (NR/CB/leather). The NR/CB/leather composites were prepared by thermal compression with 60 phr of CB and 60 or 80 phr of leather waste. In accordance with Brazilian sanitary laws, we exposed these composites for 24 h to bleach (B) and a disinfectant with the aim of simulating a true everyday cleaning use. The deconvolution of the impedance semicircles was carried out, and two relaxation phenomena around linear relaxation frequencies of about 10 5 and 10 6 Hz were found and associated mainly with charge carriers from CB and leather waste. With the addition of leather, the electrical conductivity of the composites increased two orders of magnitude from 5.70 3 10 26 for the NR/CB to 7.97 3 10 24 S/cm for NR/CB/leather-60 phr B. These results point to the possibility of using these composites as an antistatic flooring once they exhibit acceptable values of electrical conductivity and once they withstand, from the structural, morphological, and electrical point of view, exposure to sanitizing agents. Furthermore, the production of these composites will add value to and enable an environmentally acceptable disposal of leather waste.

Processing and characterization of waste leather based polycaprolactone biocomposites

“…This is due to the agglomeration of WLB fibers at higher loading (above 20%) which increased the defects in composites. Zhang et al observed a decrease in EB value for PLA natural fiber composites with increase in natural fiber content . They attributed it to the nucleating ability of natural fiber which increases the crystallization of PCL which in turn decrease the EB value.…”

“…Composites based on leather wastes as fillers are reported to be useful for many applications such as in construction materials, automobile interior moldings, heat and sound insulating boards, shoe soles, flooring materials, and moldings with good anti‐static properties, air permeability and good appearances . Ruiz et al developed material based on natural rubber and leather tannery waste to be applied as antistatic flooring. However, utilization of waste leather as filler in biodegradable polymer based composites has not been reported till now.…”

Review - Characterization of rubber compounds with post-industrial leather waste // Revisión - Caracterización de compuestos de caucho con residuos de cuero posindustrial

“…La preparación de los compuestos fue llevado a cabo en un molino abierto de acuerdo a la norma ASTM D 3182 [58], El sistema de vulcanización consistió de óxido de zinc (5 phr), ácido esteárico (3 phr), azufre (2.5 phr) y ZMB-2 (1 phr), y un sistema de aceleración que consistió en MBTS (1.2 phr) y TMTD (0.4 phr). Los tiempos de vulcanización de los compuestos fueron obtenidos antes del moldeo por compresión mediante ensayos reométricos [59].…”

“…Los materiales antes y después de la exposición a los diferentes agentes químicos fueron caracterizados mediante FTIR, SEM-EDX, medidas eléctricas de corriente directa y alterna, dureza, resistencia a la tracción, a la compresión y a la abrasión [59]. A partir de los resultados de las micrografías SEM y las difracciones de rayos X, se puede concluir la presencia de metales como Na, Al, Si, k, Ca, Fe y Zn, adicionalmente fue encontrado un pico de cromo y este fue relacionado a la base CrOHSO4 utilizada en el proceso de teñido del cuero.…”

“…Las características eléctricas y de resistencia frente a los agentes de limpieza, permiten establecer que estos compuestos pueden ser utilizados en la fabricación de pisos antiestáticos. [59] Los compuestos elaborados a partir de caucho natural y residuos de cuero, fueron empleados en otro trabajo para la elaboración de un material compuesto espumado. Los residuos de cuero fueron incorporados en los compuestos en proporciones de 20, 40 y 60 phr, estos residuos de cuero fueron analizados para obtener información de su pH, de su contenido de humedad, de cenizas, de cromo y adicionalmente del nitrógeno total.…”