No abstract

In this work, a novel silicone rubber composite with low smoke, good mechanical property, and excellent flame retardant was prepared by introducing melamine (MEL), starch (St), and sepiolite (SEP) into SR. The effect of the amount of SEP on the mechanical properties of SR composites was investigated. The results showed that the mechanical properties were optimal when the amount of SEP was 30 phr. The tensile sections of the composites were characterized by SEM. The flame retardant properties of the composites were evaluated by oxygen index, vertical combustion, and cone calorimetry test (CCT). The thermal stability of the composites was tested by TGA. The flame retardant mechanism of the composites was also discussed. It was found that the strength and stability of the carbon layer of the composite were remarkably enhanced, and the flame retardant properties of the materials were improved with the addition of SEP. The SEM images of CCT carbon residues revealed that the carbon layer of the composite with SEP was more stable and had fewer cracks than that without SEP. This work provides new insights for the preparation of high‐performance SR composite.

With the increasing demand for eco-friendly, non-petroleum-based natural rubber (NR) products, sepiolite, a naturally abundant, one-dimensional clay mineral, has been identified as a suitable material for reinforcing NR through the latex compounding method. To create superior NR/sepiolite composites, three silane coupling agents with different functional groups were used to modify sepiolite in situ via grafting or adsorption during the disaggregation and activation of natural sepiolite, which were subsequently mixed with natural rubber latex (NRL) to prepare the composites. The results showed that the modified sepiolite improved the dispersion and interfacial bonding strength with the rubber matrix. VTES-modified sepiolite containing C=C groups slightly improved the performance but retarded the vulcanization of the NR composites, and MPTES and TESPT-modified sepiolites containing -SH and −S4− groups, respectively, effectively accelerated vulcanization, inducing the composites to form a denser crosslink network structure, and exhibiting excellent dynamic and static properties, such as the modulus at a 300% increase from 8.82 MPa to 16.87 MPa, a tear strength increase from 49.6 N·mm−1 to 60.3 N·mm−1, as well as an improved rolling resistance and abrasive resistance of the composites. These findings demonstrate that modified sepiolite can be used to produce high-quality NR/sepiolite composites with enhanced properties.

The pressure function method being different from traditional (experienced) design method. Natural balance outline design method is a tyre structure design method. Based on mathematics and mechanics reasonings, the structure and shape of the tyre were controlled by pressure function and then the structure design was further achieved. The mathematic-physical equations of the pressure function method were established. According to numerical calculation, the reasonable structure of tyre and the prediction of tyre-inflated shape could be accomplished. The pressure function method can reduce the cost and improve the design efficiency.

A new modification strategy of natural rubber (NR) with high efficiency and environmental protection is proposed to get a high‐strength natural rubber (HSNR) by wetly modifying the natural latex with cardanol emulsified by emulsifier fatty alcohol polyoxyethylene ether sodium sulfate (AES) first and then short‐term high‐temperature treatment. The obtained HSNR was characterized by Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetric analysis. Moreover, the influences of the amount of cardanol on the crystallization behavior, processability, and physicomechanical properties were also studied. The results indicated that HSNR has a higher molecular weight, gel content, Mooney viscosity, initial plastic value, and elastic modulus, exhibiting good thermal stability and high glass transition temperature. Markedly, HSNR vulcanizates had excellent mechanical strength and thermo‐oxidative aging resistance when the optimum dosage of cardanol was 1 phr. Further discussion revealed that cardanol could effectively modify NR and enhance comprehensive properties by promoting the crosslinking of molecular chains of NR and introducing phenol, which contributed to the potential value in the application field of replacing ribbed smoked sheets.