A novel filling antioxidant (Lig‐g‐RT) to improve the mechanical properties and antiaging performance of styrene‐butadiene rubber (SBR) composites was prepared by grafting antioxidant intermediate p‐aminodiphenylamine (RT) on the surface of lignin via the linkage of silane coupling agent. Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) measurements confirmed that RT was successfully grafted on the surface of lignin to produce the functionalized Lig‐g‐RT which shows a better thermal stability than lignin. Compared with SBR/lignin composite, the SBR/Lig‐g‐RT composite using latex co‐precipitation method exhibits a much better filler dispersion, which contributes to the maintain of the physical mechanical properties of SBR vulcanizates. Moreover, the SBR/Lig‐g‐RT vulcanizate exhibits less chemical crosslink concentration and higher entanglement density than SBR/lignin vulcanizate according to the Mooney–Rivlin model analysis. In addition, the stabilizing effect of lignin/Lig‐g‐RT on the carbon‐black filled SBR vulcanizates is comparable with that of commercial antioxidant N‐1,3‐dimethylbutyl‐N′‐phenyl‐p‐phenylenediamine (4020), especially the SBR vulcanizate filled with 10 phr Lig‐g‐RT obtains the optimum thermo‐oxidative aging properties. This functionalized Lig‐g‐RT not only provides an intramolecular synergistic antiaging effect for SBR vulcanizates and an improvement of filler dispersion, but greatly extends the comprehensive utilization of industrial lignin.

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Herein, a molecular dynamics simulation method was used to predict the compatibility of chloroprene rubber (CR) and decabromodiphenyl ethane (DBDPE) and to investigate the mechanical properties of CR-based composites. The limiting oxygen index and cone calorimeter measurement values indicated that the addition of DBDPE was beneficial for reducing the peak heat release rate during combustion and facilitating the formation of compact and strong char layers for carbon black-filled CR composites, resulting in efficient reduction of flammability and fire risk. Incorporation of DBDPE obviously delayed the dehydrochlorination of the CR matrix. Moreover, adding 50 phr DBDPE had little effect on the tensile strength and elongation at the break, and increased the modulus at 100% elongation by 64.3% in contrast to CR without DBDPE. However, the cold properties of CR vulcanizates decreased slightly with an increase in the DBDPE content.

In this study, we present an innovative environmental silicon-, phosphorus-, and nitrogen-triple lignin-based flame retardant (Lig-K-DOPO). Lig-K-DOPO was successfully prepared by condensation of lignin with flame retardant intermediate DOPO-KH550 synthesized via Atherton–Todd reaction between 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and γ-aminopropyl triethoxysilane (KH550A). The presence of silicon, phosphate, and nitrogen groups was characterized by FTIR, XPS, and 31P NMR spectroscopy. Lig-K-DOPO exhibited advanced thermal stability compared with pristine lignin supported by TGA analysis. The curing characteristic measurement showed that addition of Lig-K-DOPO promoted the curing rate and crosslink density to styrene butadiene rubber (SBR). Moreover, the cone calorimetry results indicated Lig-K-DOPO conferred impressive flame retardancy and smoke suppression. The addition of 20 phr Lig-K-DOPO reduced SBR blends 19.1% peak heat release rate (PHRR), 13.2% total heat release (THR), 53.2% smoke production rate (SPR), and 45.7% peak smoke production rate (PSPR). This strategy provides insights into multifunctional additives and greatly extends the comprehensive utilization of industrial lignin.