In the last decade, natural fibers have had a significant impact on the research and development of innovative composites made with natural rubber, improving their properties over those of their counterparts that incorporate polluting synthetic fibers. In recent years, this fact has stimulated the research into several modified natural rubber composites reinforced with vegetable fibers. This paper reviews the scientific literature published in the last decade about the properties and characteristics of natural vegetable fibers and natural rubber used in composites. Nowadays the use of alternative materials has become necessary, considering that synthetic materials have caused irreversible damage to the environment, being associated with global warming, for this reason research and development with materials that print a lower carbon footprint during the manufacturing process and subsequent product manufacturing. This review is an invitation to the use of vegetable fibers, as well as vegetable-type matrices, in this case natural rubber as a binder system, it is fantastic to know the different works carried out by other scientists and engineers, in this way to project new compounds linked to innovation in processes that reduce the carbon footprint and its negative impact on our planet.

Nowadays, biocomposites represent a new generation of materials that are environmentally friendly, cost-effective, low-density, and not derived from petroleum. They have been widely used to protect the environment and generate new alternatives in the polymer industry. In this study, we incorporated untreated jute fibers (UJFs) and alkaline-treated jute fibers (TJFs) at 1–5 and 10 phr into TSR 10 natural rubber as reinforcement fillers. These composites were produced to be used in countersole shoes manufacturing. Untreated fibers were compared to those treated with 10% sodium hydroxide. The alkali treatment allowed the incorporation of fibers without compromising their mechanical properties. The TJF samples exhibited 8% less hardness, 70% more tensile strength, and the same flexibility compared to their pure rubber counterparts. Thanks to their properties and ergonomic appearance, the composites obtained here can be useful in many applications: construction materials (sound insulating boards, and flooring materials), the automotive industry (interior moldings), the footwear industry (shoe soles), and anti-static moldings. These new compounds can be employed in innovative processes to reduce their carbon footprint and negative impact on our planet. Using the Lorenz–Park equation, the loaded composites examined in this study exhibited values above 0.7, which means a competitive load–rubber interaction. Scanning electron microscopy (SEM) was used to investigate the morphology of the composites in detail.

The substantial waste generated during the processing of hides and skins as well as at other stages of manufacturing is a recurring issue in the leather industry that this article attempts to address. To investigate the mechanical and thermal characteristics of the resultant composites, this study suggests using leather waste from the bovine leather industry, analyzes the tanning process, and assesses the viability of mixing this waste with natural rubber (TSR-20). Without the inclusion of leather waste, the resulting composites had exceptional tensile strength, surpassing 100% of rubber’s strength. The effective interaction of the recycled leather particles with the natural rubber matrix was evidenced using the Lorentz–Park equation. This better performance points to a competitive relationship between rubber and leather waste. The samples’ density was 10% greater than that of polybutadiene elastomers and 10% greater than that of natural leather, while the hardness was comparable to that of PVC, which is frequently utilized in the design of general-purpose soles. This suggests that waste from the leather industry can be efficiently utilized in sustainable applications, particularly in the production of leather goods and shoes, helping to valorize waste that is typically discarded. Furthermore, by encouraging the use of recycled resources in the creation of new compounds, this plan provides the rubber sector with a sustainable option. To optimize this proposal, perhaps will be necessary to identify different vulcanization systems to improve the physical mechanical properties and other uses derived from the optimizations realized. This composite can be applied in the fashion industry in order to develop new trends around the application of waste and residues for a natural design line. Through the research process, it was possible to integrate the residues into the natural rubber matrix, as evidenced in the characterization process.