This study explores the application of thermo-oxidative reclaimed ground tire rubber (RGTR) in natural rubber (NR)/styrene butadiene rubber (SBR) composite, focusing on its impact on morphology, mechanical properties, rheological behavior, vulcanization characteristics, aging resistance, tear strength and abrasion resistance. The findings revealed that RGTR enhances the tear strength and abrasion resistance of NR/SBR composites while maintaining comparable tensile strength, elongation at break, and modulus. The incorporation of RGTR reduced Mooney viscosity of the NR/SBR composites and improved flowability. It also shortened the vulcanization time and enhanced vulcanization efficiency. The NR/SBR composites with RGTR loadings below 60 phr exhibited optimal performance, achieved a maximum tear strength of 93.77 N/mm and improved abrasion resistance. However, higher RGTR content led to increased agglomeration, as evidenced by scanning electron microscopy (SEM), which showed finer dispersion at lower RGTR contents and larger aggregates at higher loadings. These findings demonstrate the potential of RGTR as a sustainable additive for enhancing specific properties in NR/SBR composites, contributing to both performance optimization and waste tire management.

Ground sugarcane bagasse (GSB), an agro-waste rich in lignocellulosic components, was studied as a sustainable bio-filler in natural rubber (NR) tread compounds to lessen reliance on petroleum-derived carbon black (CB). A control formulation with 45 phr CB was compared to hybrid formulations with 40, 35, and 30 phr CB mixed with 5, 10, and 15 phr GSB. Tensile strength 13.1 MPa, elongation at break 700%, and hardness 67 Shore A were all optimally balanced by the compound containing 10 phr GSB (S2), while also exhibiting good cure behavior and thermal stability. Improved tire performance characteristics were confirmed by a dynamic mechanical study, which showed that tan δ at 60 °C decreased by 8.0% (resulting in lower rolling resistance) and increased by 3.9% (improving wet traction) at 0°C. The Payne effect showed improved filler dispersion as a result of GSB partially replacing CB. The results show that appropriately dispersed GSB can partially reinforce NR, enhancing energy efficiency and sustainability. However, larger GSB loadings decrease modulus, tear strength, and abrasion resistance due to lower interfacial adhesion and the presence of micro-voids. According to this study, pulverized sugarcane bagasse shows promise as an environmentally friendly filler for green tire applications, promoting the circular economy and lowering the carbon footprint of rubber compounding.

The present study has proposed a straightforward method to improve the reprocessability of modified natural rubber (NR) by blending it with gelatin (GT). The reprocessable characteristics of these blends were evaluated based on their remolding capabilities and mechanical recovery performance. In this method, poly(vinylbenzyl chloride) (PVBC) was first grafted onto NR chains to create graft copolymers known as NR-g-PVBC. The benzyl chloride groups in the graft copolymers were subsequently converted into quaternary ammonium groups, referred to as NR-g-QPVBC. This modification enabled ionic crosslinking when NR-g-QPVBC reacted with ethylenediamine tetraacetic acid. Blends were created by incorporating GT powder into the NR-g-QPVBC latex. The optimal loading level of GT was determined to be 30 wt%, as the resulting film exhibited the highest recovery of tensile properties. Initially, the film's tensile strength was measured at 15 MPa. After being remolded at 160 °C, the tensile strength decreased to 9.3 MPa, resulting in a recovery rate of 60.7% and withstanding a tensile strain of 144%. Although the NR-g-QPVBC/GT films could be remolded, their tensile properties declined with increasing remolding cycles. Therefore, this work demonstrated a practical method for producing NR-based films that could be reshaped through hot-pressing after being formed into products, increasing their reusability.

This work introduces an innovative method to enhance the compatibility of nylon-12/natural rubber thermoplastic elastomers by utilizing hydroxyl telechelic natural rubber as a reactive compatibilizer and natural fibers as reinforcement. Hydroxyl telechelic natural rubber was synthesized from natural rubber via oxidative cleavage to carbonyl telechelic natural rubber, followed by reduction with sodium borohydride. Proton nuclear magnetic resonance (¹H-NMR) and Fourier transform infrared spectroscopy (FTIR) verified the structure. Incorporating hydroxyl telechelic natural rubber into nylon-12/natural rubber (40/60 wt%) blends significantly enhanced interfacial adhesion, improving tensile strength and elongation at break compared to the uncompatibilized mix. Dynamic vulcanization using phenolic resin achieved an optimal balance of strength and ductility. The incorporation of areca husk fiber enhanced tensile strength, hardness, and solvent resistance, with a slight decrease in ductility and tear strength. Rheological analysis indicated that hydroxyl telechelic natural rubber increased melt viscosity due to improved phase interactions, while dynamic vulcanization reduced the melt flow index through network formation. Solvent uptake experiments confirmed that hydroxyl telechelic natural rubber, areca husk fiber, and SP-1045 vulcanizing agent minimized swelling in isooctane, toluene, and diesel oil.

Powder-free natural rubber gloves for chemical migration resistance of food-contact grade are prepared using a variety of fillers, including ground calcium carbonate (GCC), precipitated calcium carbonate (PCC), aluminum silicate (AS), and barium sulfate (BS)-filled natural rubber (NR), respectively. The properties of NR gloves, including mechanical, dynamic mechanical, and thermal properties, were investigated. Furthermore, the overall migration test of NR gloves was conducted according to the regulations for food contact gloves (EU Regulation No. 10/2011), using 3% acetic acid as the simulant. Among the fillers studied, the plate-like particles of AS facilitated the most effective filler-rubber interactions and reinforcement in AS-filled natural rubber (NR/AS). Consequently, the highest crosslink density, force at break, and damping properties of NR gloves were achieved by applying AS in the NR matrix. Moreover, the lowest overall migration level was observed for NR/AS with a value of 5.35 mg/dm², which complies with EU Regulation (overall migration of food simulants shall not exceed 10 mg/dm²). Therefore, NR gloves filled with AS are suitable for food-contacting NR gloves.