Application of Silica Supported Calix[4]arene Derivative as Anti-reversion Agent in Tire Tread Formulation

In this research the influence of the silica supported calix[4]arene derivative (SS-Calix) on the reversion resistance, mechanical properties and thermal behavior of NR/BR tire tread formulation was investigated by the oscillating disc rheometer, FTIR, TGA and tensile testing. The results revealed that the reversion behavior of NR/BR vulcanizate is affected by SS-Calix. The data obtained from curing characteristics and thermal stability of test pieces indicate that, SS-Calix acts as an anti-reversion for rubbery materials that are exposed to thermal shock in the early stages of temperature rise. It’s predicted that these results are due to the interaction between the OH groups present in the SS-Calix surface and the carbon of the polymer chains. The broad peak observed in the IR spectrum around 1824 cm−1 which is referred to C=O bond, confirms this prediction. In addition, the presence of SS-Calix in compound causes to increase modulus and hardness but reduce elongation and resilience.

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Controlling the Thermal Stability of Kyanite-Based Refractory Geopolymers

Materials ◽

10.3390/ma14112903 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2903

Author(s):

Juvenal Giogetti Nemaleu Deutou ◽

Rodrigue Cyriaque Kaze ◽

Elie Kamseu ◽

Vincenzo M. Sglavo

Keyword(s):

Mechanical Properties ◽

Thermal Stability ◽

High Strength ◽

Treatment Temperature ◽

Strength Development ◽

Particle Sizes ◽

Cold Setting ◽

Thermal Stability Of ◽

Geopolymer Composites ◽

Refractory Composites

The present project investigated the thermal stability of cold-setting refractory composites under high-temperature cycles. The proposed route dealt with the feasibility of using fillers with different particle sizes and studying their influence on the thermo-mechanical properties of refractory geopolymer composites. The volumetric shrinkage was studied with respect to particle sizes of fillers (80, 200 and 500 µm), treatment temperature (1050–1250 °C) and amount of fillers (70–85 wt.%). The results, combined with thermal analysis, indicated the efficiency of refractory-based kyanite aggregates for enhancing thermo-mechanical properties. At low temperatures, larger amounts of kyanite aggregates promoted mechanical strength development. Flexural strengths of 45, 42 and 40 MPa were obtained for geopolymer samples, respectively, at 1200 °C, made with filler particles sieved at 80, 200 and 500 µm. In addition, a sintering temperature equal to 1200 °C appeared beneficial for the promotion of densification as well as bonding between kyanite aggregates and the matrix, contributing to the reinforcement of the refractory geopolymer composites without any sign of vitrification. From the obtained properties of thermal stability, good densification and high strength, kyanite aggregates are efficient and promising candidates for the production of environmentally friendly, castable refractory composites.

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