Ionic crosslinking of bromobutyl rubber (BIIR) composites was prepared using butylimidazole (IM) and ionic liquid (IL), combined with carbon nanotubes (CNT) and conductive carbon black (CCB) to enhance the intrinsic properties and heal ability of the resulting composites. Variation in the BIIR/CNT-CCB/IM/IL ratios was investigated to determine the appropriate formulation for healing the composites. Results showed that the mechanical properties were increased until the IM:IL:CNT/CCB ratio reached 1:1:1/1.5, corresponding to the optimal concentration of 5:5:5/7.5 phr. Thermo-oxidative degradation, as indicated using temperature scanning stress relaxation (TSSR), demonstrated the decomposition of the composites at higher temperatures, highlighting the superior resistance provided by the proper formulation of BIIR composites. Additionally, the conditions for the healing procedure were examined by applying pressure, temperature, and time. It was observed that the composites exhibited good elasticity at 0 °C and 60 °C, with a high rate of re-crosslinking achieved under appropriate pressure and temperature conditions. This research aims to develop a formulation suitable for the tire tread and inner liner of commercial car tires together with artificial skin products.Keywords:bromobutyl rubber;self-healing;re-crosslink;tire application
Flexible self-healing composite was fabricated based on blending the bromobutyl rubber (BIIR) and epoxide natural rubber (ENR) filled with hybrid fillers of carbon nanotubes (CNT) and carbon black (CB). To achieve self-recoverability, modification of BIIR was carried out through butyl imidazole (IM), and the healing capability was then activated by the addition of bis(triethoxysilylpropyl)tetrasulfide (TESPT), which resulted in good dispersion of CNT/CB in BIIR/ENR blends. The silanization of TESPT and CNT/CB hybrid filler surfaces was confirmed by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Adding CNT/CB and incorporating TESPT into the composites effectively improved the curing and mechanical properties of the blends in terms of estimated crosslink density and tensile modulus. Further, the self-healing propagation rate was enhanced by the thermal conductivity of fillers and the ion–dipole intermolecular forces between the rubber chains, leading to the highest abrasion resistance and electrical conductivity. Using an environmentally friendly process, the recyclability of the self-healing composites was improved by the re-compression of the samples. With this, the constant conductivity relating to the rearrangement of the CNT/CB network is examined related to the usability of the composites at 0 and 60 °C. The conductive composites filled with a TESPT silane coupling agent present an opportunity for vehicle tires and other self-repairing applications.Keywords:natural rubber;self-healing;silane coupling agent;butyl rubber;tire application
Bao Qin,Junhao Jiang,Hongbin Hou,Qinggang Wang,Guangye Liu
Rubber materials require nanofiller reinforcement to overcome their intrinsic low modulus and stress-at-elongation limitations. Although traditional carbon black (CB) enhances mechanical properties, its aggregation-induced filler networks exacerbate dynamic hysteresis and heat generation. Silica nanoparticles reduce rolling resistance but face challenges in limited tensile strength improvements. Emerging fillers like carbon nanotubes and graphene suffer from dispersion issues or excessive heat generation. Herein, monodisperse sodium titanate (Na 2 Ti 3 O 7 , NTO) nanorods with high aspect ratios (2–300) were synthesized via a one-step hydrothermal method and incorporated into CB/natural rubber (NR) composites. The NTO(20)/CB(30)/NR system exhibited superior static/dynamic performance: tensile strength (+16%), stress at 100% elongation (+211%), 28% lower compression heat build-up, 204% extended fatigue life, and 11% reduced Akron abrasion loss. These enhancements stem from NTO's high surface area strengthening rubber-filler interactions and rod-like morphology disrupting CB networks. This work demonstrates a scalable hybrid filler strategy to advance sustainable rubber technologies for high-performance industrial and mobility applications.
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