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 study investigates a sustainable hybrid-filler strategy for natural rubber (NR) compound by partially replacing petroleum-based carbon black (CB) with talc and introducing a silane coupling agent to mitigate interfacial incompatibility. Compounds containing CB, CB+talc and CB+talc+increasing silane were produced via two-stage mixing and characterized for morphology (dispersion/mapping), curing and flow behavior (differential scanning calorimetry DSC/moving die rheometer, MDR/Mooney), crosslink density (Flory–Rehner), physical–mechanical properties, dynamic performance (Payne effect/heat build-up/tension–fatigue), and thermal stability (aging/thermogravimetric analysis,TGA). Talc reduced the compound viscosity, offering processing benefits. The swelling test indicated that talc decreased crosslink density, but silane recovered it, forming covalent linkages. Tensile strength and elongation at break were improved without altering hardness. Dynamically, talc increased heat build-up, whereas silane inverted the trend and reduced the temperature rise gradually from 41.5 to 29.4°C at 2 phr. Fatigue life was improved with talc (~10%), and further with silane (up to 36% at 2 phr), highlighting a favorable stiffness–fatigue balance with compatibilization. Overall, partial CB replacement by talc, in combination with silane, delivers meaningful sustainability gains with improved dynamic performance while preserving key mechanical properties of NR compounds.

This study investigates eugenol as an alternative to mitigate environmental pollution and worker hazards associated with antioxidant N-(1,3-dimethyl)butyl-N′-phenyl-p-phenylenediamine (4020) while aligning with trends toward sustainable additives. Silica/natural rubber (NR) composites with varying ratios of eugenol and 4020 were prepared to assess their aging resistance, mechanical properties, and the synergistic antioxidant effects. Thermogravimetric analysis, cross-linking density experiments, thermo-oxidative aging tests, and oxidation induction tests revealed the highest thermo-oxidative aging resistance when 0.5 phr of 4020 was substituted with eugenol. When 1.0 phr of 4020 was replaced by eugenol, the antioxidant properties of the composites matched those containing 2.0 phr of 4020. However, when eugenol exceeded 1 phr, the antioxidant properties gradually decreased. DIN wear tests showed optimal wear resistance when 1 phr of 4020 was replaced with eugenol. These findings suggest that 50% of conventional antioxidants can be substituted with eugenol without compromising material properties. The partial substitution of eugenol in silica/NR composites proves eugenol can act as a sustainable alternative, providing comparable antioxidant capacity while reducing environmental impact.

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.

Thermoplastic natural rubber (TPNR) is widely used across industries due to its unique blend of elasticity and processability. Thermoplastic vulcanizates (TPVs) based on thermoplastic polyurethane (TPU) offer excellent mechanical properties and flexibility, yet often require enhanced elasticity and durability. Blending TPU with natural rubber (NR) is promising; however, phase incompatibility reduces mechanical strength and thermal stability. To address this, epoxidized NR (ENR) was employed as a compatibilizer in TPU/NR blends. ENR’s hydrocarbon backbone interacts with crosslinked NR, while epoxy groups enhance adhesion with TPU. Incorporating 3 phr of ENR significantly improved crosslinking, increased tensile strength by 41.1%, enhanced stress relaxation, and lowered the glass transition temperatures of both TPU and NR phases in the TPU/NR blends. These effects are attributed to improved chemical bridging between TPU and NR. However, excess ENR disrupts phase compatibility, causing polymer entanglement and reduced strength. Optimizing ENR content is essential for developing high-performance TPU/NR blends. Printability was demonstrated using the material extrusion additive manufacturing (MEx-AM) fused deposition modeling (FDM), showing potential for flexible applications like splints and medical devices.