Determination of the Crosslink Density of Silica Filled Styrene Butadiene Rubber Compounds by different Analytical Methods

The crosslink density (CLD) of rubber compounds has a great effect on the properties of the final product. For this reason, a suitable characterization method is required to understand and optimize the final performance of rubber materials. Four different experimental techniques were used to determine the crosslink density of silica filled Styrene Butadiene Rubber (SBR) composites: equilibrium swelling experiments, stress-strain measurements using the Mooney Rivlin theory, freezing point depression temperature tests and Temperature Scanning Stress Relaxation (TSSR) measurements. The evaluation of these different techniques shows that the results obtained follow a similar trend for all four methods. The results from the Mooney Rivlin and TSSR measurements correlate the best. These two techniques are the least affected by the presence of fillers and are the less time consuming ones. Furthermore, they also show the best correlation with the mechanical properties of the studied compounds

How to Combine Elasticity with Fire Protection?:Progress in Ceramifiable Composites Development

One of the most unique features of polymeric materials is their ability to undergo elastic, reversible deformation. A group of polymers exhibiting such properties owns even an exceptional name – elastomers. The relevance of elastic properties is undeniable in numerous industrial applications form high-performance tyres to seals, gaskets, hoses, cables, and plenty others functional materials manufacturing. However, the hydrocarbon or siloxane macromolecular structure providing elastomeric properties bears also some considerable drawbacks. High flammability is one of the most severe among them. Grand prevalence of polymer materials poses a serious fire threat in households, public, industrial and commercial buildings, as well as mass or private transport vehicles. In order to reduce the fire threat, different approaches with regard to material development and fire-safety are explored. Increase of fire resistance of polymer materials can be provided by chemical modification of the polymer macromolecules or incorporation of flame retardant additives. These additives can be divided according to the mechanism of their action into chemical (suppressing the radical mechanism of fire growth), physical (heat consumption or dissipation, enhancing the polymer/fire barrier interphase) or physicochemical flame retardants. Very often the physical-flame retardants are also called passive-flame retardants due to the fact that they do not generate any harmful products during the fire suppressing mechanism. This makes them more suitable for polymers devoted to applications in densely populated places. One of the most promising paths of increasing the fire resistance of polymers is the development of ceramifiable composites. These materials consist of a polymeric (most often elastomeric) continuous matrix and a properly designed mix of fillers triggering structural conversion under fire/elevated-temperature conditions from elastic composite to brittle ceramics [1]. The ceramic structure formed exhibits continuous morphology and high mechanical and thermal-barrier properties, improving not only fire resistance of the composite but also providing a significant fire/heat protection to the element coated by the composite. Therefore, the interest in these composites is growing considerably. Starting with their utilization as special, fire-resistant cable covers [2-4] and developing into coating for construction-steel elements [5] or anti-ablative materials [6]. The aim of this work is to review current trends in the ceramifiable composites development. Mechanisms of the ceramification phenomena will be presented and discussed, with an emphasis on the latest physical [7] and physicochemical [8] approaches. Tailoring of properties of the composites by functional additives [9, 10] and using new polymers as the composites matrices [11, 12] will also be reviewed. 1. L.G. Hanu, O.P. Simon, J. Mansouri, R.P. Burford and Y.B. Cheng, Journal of Materials Processing Technology 153-154, 401 (2004). 2. S. Hamdani, C. Longuet, J-M. Lopez-Cuesta and F. Ganachaud, Polymer Degradation and Stability 95, 1911 (2010) 3. S. Hamdani-Devarennes, A. Pommier, C. Longuet, J-M. Lopez-Cuesta and F. Ganachaud, Polymer Degradation and Stability 96, 1562 (2011) 4. S. Hamdani-Devarennes, C. Longuet, R. Sonnier, F. Ganachaud and J-M. Lopez-Cuesta, Polymer Degradation and Stability 98, 2021 (2013) 5. B. Gardelle, S. Duquesne, P. Vandereecken and S. Bourbigot, Journal of Fire Sciences 32, 374 (2014) 6. G. Zhang, F. Wang, Z. Huang, J. Dai and M Shi, Materials 9, 723 (2016) 7. X. Zhang, Y. Guan, Y. Xie and D. Qiu, RSC Advances 6, 7970 (2016) 8. S. Hu, F. Chen, J-G. Li, Q. Shen, Z-X Huang and L-M Zhang, Polymer Degradation and Stability 126, 196 (2016) 9. R. Anyszka, D.M. Bielinski, Z. Pedzich and M. Szumera, Journal of Thermal Analysis and Calorimetry 119, 111 (2015). 10. M. Imiela, R. Anyszka, D.M. Bielinski, Z. Pedzich, M. Zarzecka-Napierala and M. Szumera, Journal of Thermal Analysis and Calorimetry 124, 197 (2016). 11. R. Anyszka, D.M. Bielinski, Z. Pedzich, P. Rybinski, M. Imiela, M. Sicinski, M. Zarzecka-Napieraa, T. Gozdek and P. Rutkowski, Materials 9, 604 (2016). 12. H-W. Di, C. Deng, R-M. Li, L-P. Dong and Y-Z. Wang, RSC Advances 5, 51248 (2015