Abstract:In this work, the effect of the incorporation of leather wastes from chrome tanning on the mechanical and rheometric properties of natural rubber-based composite was evaluated. Chrome content in leather wastes diminished as a result of a chemical treatment with a sodium bicarbonate solution. The treatment also improved the tensile properties of composites with 0, 20 and 40 parts per hundred rubber of leather wastes with particle size between 590 and 840 µm. In a second stage of the experimental work, 0, 20, 40… Show more
“…The peaks of the EDS spectrum corresponding to these atoms decrease or disappear when the neutralization treatment is carried out with the sodium bicarbonate solution. 12 Figure 4.SEM-EDS from leather wastes (a) untreated and (b) chemically treated with the sodium bicarbonate solution. SEM: scanning electron microscopy; EDS: energy dispersive X-ray spectroscopy.…”
Section: Resultsmentioning
confidence: 99%
“…These composites have exhibited a high compatibility between the residues and the matrix, favoring the improvement in mechanical properties such as hardness and tensile strength. 6–12 Additionally, it has been found that the addition of these residues aids the incorporation of up to 600 phr of recycled rubber into rubber formulations, facilitating their processing without a significant decrease of the vulcanization parameters. 7,8…”
Section: Introductionmentioning
confidence: 99%
“…5,10 For this reason, studies have been carried out where post-industrial leather wastes are evaluated after being subjected to chemical neutralization treatments, to reduce their acidic nature, and thus guaranteeing greater homogeneity in the vulcanization characteristics of rubber composites. 7,8,12…”
In this work, the effect of particle size and the content of leather wastes on the processability, vulcanization, and mechanical properties of a natural rubber/leather wastes composites was studied. From a reduction process, leather waste was later sieved to classify particles smaller than 0.6 mm and particles between 0.84 and 2 mm, hereafter called fine and coarse residues, respectively. The morphology of the wastes was analyzed from scanning electron microscopy micrographs. Natural rubber/leather wastes composites with 20, 40, 60, 80, and 100 phr (parts per 100 parts of rubber) of treated leather wastes were obtained in a torque rheometer. Mixtures with coarse wastes exhibited a slightly higher torque than mixtures with the fine wastes; additionally, increasing the wastes content yields in an increased torque during the final stage of the process. The addition of leather wastes increased the vulcanization time and stiffness of the composites; additionally, materials with fine wastes showed lower vulcanization times compared to materials with coarse wastes. Composites with fine leather wastes exhibited higher density and tensile modulus than materials with coarse wastes; however, only the composites with 80 and 100 phr of wastes showed a statistically significant difference in hardness values. The specific energy consumption (SEC) was calculated from the results obtained with the torque rheometer; it was found that for all the formulations the SEC decreased as the phr of leather residues increased. It was found that it is possible to use leather wastes in natural rubber composites, to obtain adequate materials feasible for some applications.
“…The peaks of the EDS spectrum corresponding to these atoms decrease or disappear when the neutralization treatment is carried out with the sodium bicarbonate solution. 12 Figure 4.SEM-EDS from leather wastes (a) untreated and (b) chemically treated with the sodium bicarbonate solution. SEM: scanning electron microscopy; EDS: energy dispersive X-ray spectroscopy.…”
Section: Resultsmentioning
confidence: 99%
“…These composites have exhibited a high compatibility between the residues and the matrix, favoring the improvement in mechanical properties such as hardness and tensile strength. 6–12 Additionally, it has been found that the addition of these residues aids the incorporation of up to 600 phr of recycled rubber into rubber formulations, facilitating their processing without a significant decrease of the vulcanization parameters. 7,8…”
Section: Introductionmentioning
confidence: 99%
“…5,10 For this reason, studies have been carried out where post-industrial leather wastes are evaluated after being subjected to chemical neutralization treatments, to reduce their acidic nature, and thus guaranteeing greater homogeneity in the vulcanization characteristics of rubber composites. 7,8,12…”
In this work, the effect of particle size and the content of leather wastes on the processability, vulcanization, and mechanical properties of a natural rubber/leather wastes composites was studied. From a reduction process, leather waste was later sieved to classify particles smaller than 0.6 mm and particles between 0.84 and 2 mm, hereafter called fine and coarse residues, respectively. The morphology of the wastes was analyzed from scanning electron microscopy micrographs. Natural rubber/leather wastes composites with 20, 40, 60, 80, and 100 phr (parts per 100 parts of rubber) of treated leather wastes were obtained in a torque rheometer. Mixtures with coarse wastes exhibited a slightly higher torque than mixtures with the fine wastes; additionally, increasing the wastes content yields in an increased torque during the final stage of the process. The addition of leather wastes increased the vulcanization time and stiffness of the composites; additionally, materials with fine wastes showed lower vulcanization times compared to materials with coarse wastes. Composites with fine leather wastes exhibited higher density and tensile modulus than materials with coarse wastes; however, only the composites with 80 and 100 phr of wastes showed a statistically significant difference in hardness values. The specific energy consumption (SEC) was calculated from the results obtained with the torque rheometer; it was found that for all the formulations the SEC decreased as the phr of leather residues increased. It was found that it is possible to use leather wastes in natural rubber composites, to obtain adequate materials feasible for some applications.
“…Currently, rubber composites incorporated with various reinforcing materials are gaining momentum due to the wide array of industrial applications connected to day-to-day life and in fields like aircraft tires, sports goods, gaskets, belts, etc. 15–17 These materials in NR are highly effective in enhancing the processing and mechanical properties of the prepared composites. Numerous reports on the reutilization of various industrial wastes as reinforcing fillers are available in literature.…”
Reutilization of industrial waste is one of the emerging strategies to combat solid waste disposal for the protection of our environment. The present work describes a novel and economic approach to reutilize finely ground shoe sole scrap, a thermoset polyurethane-based waste (PUW) material generated during shoe sole production in footwear industries as an efficient reinforcing filler in natural rubber (NR). Shoe sole scrap was ground to fine powder and characterized by various analytical techniques. NR-PUW composites were prepared using 0–20 phr (parts per hundred of rubber) of PUW. The cure characteristics, mechanical, thermal, and morphological properties of prepared composites were studied. Composite with 5 phr PUW showed a remarkable improvement in tensile strength by 10% and modulus at 300% elongation increased by 9% compared to that of neat sample. A considerable increase in abrasion resistance and tear strength was also observed in 5 phr PUW loaded composites. Other mechanical properties like hardness, heat build-up and compression set showed a regular increase with further filler loading. To estimate the level of interfacial adhesion between the filler and the matrix, the experimental values of tensile strength were compared with Nicolais–Narkis (N–N), Lu, and Turcsányi–Pukànszky–Tüdõs (T–P–T) models and elastic modulus values with Einstein and Guth and Smallwood models. The tensile strength values are in agreement with T-P-T model (B = 4), up to 5 phr PUW proving the better adhesion between NR and PUW at lower filler loadings. At higher PUW loading, the experimental results are approaching Lu and N–N models indicating that this adhesion is collapsed. The incorporation of PUW as a filler in NR does not adversely impact the thermal stability of prepared composites. The results obtained are not only promising from a circular economy perspective, but also is contributive in production of high-performance, low-cost NR composites for various industrial applications.
“…Nevertheless, due to the greater awareness of environmental issues, the management of solid tanned waste over the past few years has taken on a primary role for the tanning industries. Interest has recently renewed for solid tanned waste in the field of polymers [20][21][22][23].…”
Zero-waste is an ambitious goal to encourage sustainable production, consumption optimum recycling and resource recovery. The recycling and resource recovery of chrome-tanned leather waste is a difficult proposition because of the three-dimensional chemical network of collagen, which renders leather waste incompatible to polymer matrices. Many attempts have been undertaken to reuse leather waste, most of them require technological processes and challenging chemical pretreatments, which make the reuse an economically disadvantageous industrial operation. The paper aims to show how a very fine separation of leather solid waste leads to raw materials suitable for mixtures with natural rubber, without any chemical pretreatment. In other words, the paper intends to be a stimulus to manage leather solid waste carefully to start a cleaner and more profitable production. In particular, various industrial compounds containing different concentrations of post-tanning dyeing, or chrome shaving or oil-tanning and natural rubber were vulcanized through a standard preparation. Some compounds were also reinforced with carbon black and the vulcanization kinetics were monitored through rheometer. Experimental results indicate that there exists an optimal concentration of waste such that post-tanning dyeing post-tanning and chrome shaving are suitable for manufacture floor mats, soles and heels while oil-tanning waste can be used for making hose or conveyor belts. The mechanical performances of the articles prepared by direct mixing with leather waste are the same as those of commercially distributed rubber products.
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