Preparation of silica-supported 2-mercaptobenzimidazole and its antioxidative behavior in styrene-butadiene rubber

Synthesis and Properties of a Novel Reactive and Low-Migration-Resistant Antioxidant and Its Application in Rubber Composites

The addition of antioxidants to rubber is one of the most economical and effective methods for delaying rubber aging. However, antioxidant migration can cause environmental pollution. To address this issue, a new reactive antioxidant was synthesized via the chemical bonding of glycidyl methacrylate (GMA) and p-aminodiphenylamine (PPDA). The product was characterized by Fourier-transform infrared spectroscopy, which confirmed the successful reaction between GMA and PPDA, resulting in a compound with the expected structure. The mixture was then combined with a composite of styrene-butadiene rubber and carbon black. The tensile strength, antioxidant properties, migration, and RPA of the resulting materials were tested and compared with those of the commercial antioxidants N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-isopropyl-N'-phenyl-1,4-phenylenediamine, and poly(1,2-dihydro-2,2,4-trimethylquinoline). After the glycidyl methacrylate antioxidant was grafted onto p-aminodiphenylamine, it became highly compatible with and dispersed in the rubber matrix. The antiaging and antimigration properties of the rubber antioxidants were enhanced without damaging the mechanical properties of the rubber matrix. The short-term and long-term antiaging and antimigration properties of this antioxidant are superior to those of commercially available antioxidants.

The Improvement of Kaolinite Supported Cerium Oxide for Styrene-Butadiene Rubber Composite: Mechanical, Ageing Properties and Mechanism

Kaolinite supported cerium oxide (CeOx/Kaol) was successfully prepared via a deposition method and used to improve the mechanical and aging properties of styrene-butadiene rubber (SBR) composite. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results showed that cerium oxide has a successfully loading and fine distribution on the edge and surface of kaolinite. Fourier transform infrared (FT-IR) spectroscopy indicated that cerium oxide may interact with the surface hydroxyls of kaolinite. The CeOx/Kaol material had a uniform dispersion in the resulting SBR composite. The loading of cerium oxide on Kaol increases the scorch time (t₁₀) and curing time (t₉₀) of the filled SBR composites relative to the pure SBR. The mechanical parameters of the filled SBR composites were increased significantly. The tensible strength and tear strength at 40 phr content with 4% CeOx loading reached 12.85 Mpa and 51.16 kN/m, which were increases of 35.9% and 38.3%, respectively, relative to that of the SBR filled with raw Kaol. The anti-ageing characteristic of the resulting composite showed an obvious improvement with the loading of CeOx. Meanwhile, the reinforcement and anti-ageing mechanisms of the CeOx/Kaol were proposed. These results were attributed to the complexation between Ce elements on the surface of Kaol and rubber chains through a double bond. This could improve the incorporation between rubber molecules and filler particles, and restrict rubber chain motion via trapping rubber chains.

Enabling Superior Thermo-Oxidative Resistance Elastomers Based on a Structure Recovery Strategy

Thermo-oxidative process leads to the structure damage of elastomers, such as the scission of main chains and destruction of crosslinks. The problem that damaged structure brings about the deterioration of mechanical properties has not been solved by the conventional anti-aging methods. Inspired by self-healing process, a structure recovery strategy for recovering the damaged structure induced by thermo-oxidative process is proposed, which endows elastomers with superior thermo-oxidative resistance. The high reactivity between 1,3-diisopropenylbenzene and free radicals realizes high recovery efficiency (from 83% to 118%); the changes in topology structure during recovery process make much more rubber chains bear external stress and improve mechanical properties significantly (from 18.5 to 29.6 MPa). This work paves the way for the development of elastomers with superior thermo-oxidative resistance, meanwhile this work is helpful to push the theoretical research of self-healing to practical application.

Novel Hybrid Biomass Anti-Aging Filler for Styrene-Butadiene Rubber Composites with Antioxidative and Reinforcing Properties

Antioxidants are normally utilized to extend the service life of polymers due to the strong reducibility of the phenolic hydroxyl group of the hindered phenol structure. Inspired by this characteristic, we have introduced green tea polyphenol (TP) supported on a silica surface containing considerable phenolic hydroxyl groups to obtain a novel biomass anti-aging filler (BAF, denoted as silica-s-TP) to reinforce and improve the anti-aging property of rubber composites. The applying of silica-s-TP to enhance the thermal-oxidative stability and ultraviolet light (UV) aging resistance of styrene-butadiene rubber (SBR) was evaluated. The hybrid biomass anti-aging filler could not only uniformly disperse in the rubber matrix, giving rise to the excellent mechanical properties, but also enhance the properties of thermal-oxidative stability and UV aging resistance with the increasing silica-s-TP content of SBR distinctly. This study provides a mild and environmentally friendly strategy to prepare the functional biomass filler, which could be applied as not only a reinforcement filler but also an anti-aging additive in "green rubber".