Structure, physical properties, and flame retardancy of POE/NR/EG blend foams: Effect of crosslinking
DOI:
https://doi.org/10.11113/mjfas.v16n1.1418Keywords:
Polyethylene-octene elastomer, Natural rubber, Foam, Morphology, Physical propertiesAbstract
Elastomeric foams were produced by melt-mixing of polyethylene-octene elastomer (POE), natural rubber (NR), and expandable graphite (EG) in an internal mixer. The blend was later foamed by compression-molding method. EG was used as a filler to enhance flame retardancy of the blend foams. Dicumyl peroxide (DCP) was used as curative to crosslink the blend foams. The influence of DCP content (0.5, 0.7, 0.9, and 1.0 part(s) by weight, pbw) on rheological properties, structure, density, mechanical properties, thermal conductivity, and flame retardancy of the POE/NR/EG blend foams was investigated. The rheological analysis showed that the melt strength/viscosity of the POE/NR/EG blend foams increased with more DCP addition due to promoted crosslinking in the blend foams. The cellular structural observation by SEM technique revealed that the POE/NR/EG blend foams had close-cell structure. Increasing DCP content, the blend foams had smaller cell and narrower cell size distribution. The degree of porosity, however, was highest for the foamed blends added with 0.7 pbw DCP, which brought about the lowest thermal conductivity. Furthermore, it was found that the density, tensile strength, elastomeric recovery, and compressive strength increased with increasing content of DCP, but the elongation at break decreased. The POE/NR/EG blend foams reached the horizontal burning level of HF-1, and their oxygen index increased in accordance with an increase of DCP content. The results indicated that an appropriate use of DCP was critical for the crosslinked POE/NR/EG blend foams with optimum cellular structure, providing the best improvement in thermal insulation properties and good flame retardancy.
References
Bian, X.-C., Tang, J.-H., Li, Z.-M., Lu, Z.-Y., Lu, A. (2007). Dependence of flame-retardant properties on density of expandable graphite filled rigid polyurethane foam. Journal of Applied Polymer Science, 104(5), 3347-3355.
Chen, X., Wu, H., Luo, Z., Yang, B., Guo, S., Yu, J. (2007). Synergistic effects of expandable graphite with magnesium hydroxide on the flame retardancy and thermal properties of polypropylene. Polymer Engineering and Science, 47, 1756-1760.
Cornish, K. (2014). Biosynthesis of natural rubber (NR) in different rubber-producing species. In S. Kohjiya & Y. Ikeda (Eds.), Chemistry, manufacture and applications of natural rubber (1st ed.). Cambridge: Woodhead publishing.
Feng, Z., Luo, Y., Hong, Y., Wu, J., Zhu, J., Li, H., Qi, R., Jiang, P. (2016). Preparation of enhanced poly (butylene succinate) foams. Polymer Engineering and Science, 56(11), 1275–1282.
Fyodor, A. D., Shutov, A. (1991). Chapter 3: Cellular structure and properties of foamed polymers. In D. Klemper & K. C. Frisch (Eds.), Handbook of Polymeric Foams and Foam Technology (2nd ed.). Munich: Hanser Publishers.
Guler, T., Tayfun, U., Bayramli, E., Dogan, M. (2017). Effect of expandable graphite on flame retardant, thermal and mechanical properties of thermoplastic polyurethane composites filled with huntite and hydromagnesite mineral. Thermochimica Acta, 647, 70-80.
Guo, R., Ren, Z., Bi, H., Song, Y., Xu, M. (2018). Effect of toughening agents on the properties of poplar wood flour/poly (lactic acid) composites fabricated with fused deposition modeling. European Polymer Journal, 107, 34-45.
Jacob, S. (2008). US Patent 7,319,121 B2. Retrieved from http://patents.com /us-7319121.html
Julyanon, J., Kaesaman, A., Sakai, T., Lopattananon, N. (2015). Improvement of structure and properties of nanocomposite foams based on ethylene-vinyl actetae (EVA)/natural rubber (NR)/nanoclay: Effect of NR addition. Key Engineering Materials, 659, 418-422.
Kamleitner, F., Duscher, B., Koch, T., Knaus, S., Schmid K., Archodoulaki, V. M. (2017) Influence of the molar mass on long chain branching of polypropylene. Polymers, 9(442), 1-15.
Kurańska, M., Cabulis, U., Auguścikc, M., Prociak, A., Ryszkowska, J., Kirpluks, M. (2016). Bio-based polyurethane-polyisocyanurate composites with an intumescent flame retardant. Polymer Degradation and Stability, 127, 11-19.
Li, G., Qi, R., Lu, J., Hu, X., Luo, Y., Jiang, P. (2013). Rheological properties and foam preparation of biodegradable poly (butylene succinate). Journal of Applied Polymer Science, 127(5), 3586–3594.
Li, L., Chen, Y., Qian, L., Xu, B., Xi, W. (2018). Addition flame-retardant effect of nonreactive phosphonate and expandable graphite in rigid polyurethane foams. Journal of Applied Polymer Science, 135(45960), 1-8.
Lopattananon, N., Wongpradit, N., Nakason, C., Kaesaman, A. (2014a). Effect of rubber compositions on foaming and properties of EVA/NR thermoplastic vulcanizates (TPVs). Journal of Rubber Research, 17, 80-95.
Lopattananon, N., Tanglakwaraskul, S., Kaesaman, A., Seadan, M., Sakai, T. (2014b). Effect of nanoclay addition on morphology and elastomeric properties of dynamically vulcanized natural rubber/polypropylene nanocomposites. International Polymer Processing, 29(3), 332-341.
Lopattananon, N., Julyanon, J., Masa, A., Kaesaman, A., Thongpin, C., Sakai, T. (2015). The role of nanofillers on NR/EVA/Clay nanocomposite in blending and foaming. Journal of Vinyl & Additive Technology, 21(2), 134–146.
Lopattananon, N., Julyanon, J., Masa, A., Thongnuanchan, B. (2018a). Effect of the addition of ENR on foam properties of EVA/NR/clay nanocomposites. International Polymer Processing, 33(1), 42-51.
Lopattananon, N., Walong, A., Sakai, T. (2018b). Influence of incorporation methods of ATH on microstructure, elastomeric properties, flammability, and thermal decompositionof dynamically vulcanized NR/PP blends. Journal of Applied Polymer Science, 135(46231), 1-12.
Lorenzetti, A., Dittrich, B., Schartel, B., Roso, M., Modesti, M. (2017) Expandable graphite in polyurethane foams: The effect of expansion volume and intercalants on flame retardancy. Journal of Applied Polymer Science, 134(45173), 1-8.
Mao, Y., Qi, R. (2008). Preparation of polyethylene–octene elastomer foams by compression molding. Journal of Applied Polymer Science, 109(5), 3249-3255.
Mngomezulu, M. E., Luyt, A. S., Chapple S. A., John, M. J. (2018) Effect of expandable graphite on thermal and flammability properties of poly (lactic acid)-starch/poly(E-caprolactone) blend systems. Polymer Engineering and Science, 58(9), 1619-1629.
Muller, R., Gérald, V., Dugand, P., Rempp, P., Gnanou, Y. (1991). Rheological characterization of the gel point: A new interpretation. Macromolecules, 24(6), 1321-1326.
Pang, X.-Y., Chang, W.-S., Chang, R., Weng, M-Q. (2018). Influence of titanium dioxide modified expandable graphite and ammonium polyphosphate on combustion behavior and physicomechanical properties of rigid polyurethane foam. International Polymer Processing, 33(1), 117-126.
Shi, L., Li, Z.-M., Zhou, Q-M., Yang, M.-B., Yin, B., Tian, C.-R., et al. (2005). Expandable graphite for halogen-free flame-retardant of high-density rigid polyurethane Foams. Polymer-Plastics Technology and Engineering, 44(7), 1323-1337.
Shih, R-S., Kuo, S-W., Chang, F-C. (2011). Thermal and mechanical properties of microcellular thermoplastic SBS/PS/SBR blend: Effect of crosslinking. Polymer, 52(3), 752-729.
Spratte, T., Plagge, J., Wunde, M., Klüpple, M. (2017). Investigation of strain-induced crystallization of carbon black and silica filled natural rubber composites based on mechanical and temperature measurements. Polymer, 115, 12-20.
Subhash, G., Liu, Q., Gao, X. L. (2006). Quasistatic and high strain rate uniaxial compressive response of polymeric structural foams. International Journal of Impact Engineering, 32(7), 1113-1126.
Sun, X., Liang, W. (2016). Cellular structure control and sound absorption of polyolefin microlayer sheets. Composites Part B: Engineering, 87, 21-26.
Svoboda, P., Poongavalappil, S., Theravalappil, R., Svobodova, D., Mokrejs, P. (2013). Effect of octene content on peroxide crosslinking of ethylene–octene copolymers. Polymer International, 62(2), 184-189.
Tayefi, M., Razavi-Nouri, M., Sabet, A. (2017). Influence of ordering and disordering of organoclay on rheological properties of uncured and cured ethylene-octene copolymer nanocomposites. Applied Clay Science, 83, 357-366.
Thirumal, M., Khastgir, D., Singha, N. K., Munjunath, B. S., Naik, Y. P. (2008). Effect of expandable graphite on the properties of intumescent flame-retardant polyurethane foam. Journal of Applied Polymer Science, 110(5), 2586-2594.
Wang, S., Qian, L., Xin, F. (2018). The synergistic flame-retardant behaviors of pentaerythritol phosphate and expandable graphite in rigid polyurethane foams. Polymer Composites, 39(2), 329-336.
Xi, W., Qian, L., Huang, Z., Cao, Y., Li, L. (2016). Continuous flame-retardant actions of two phosphate esters with expandable graphite in rigid polyurethane foams. Polymer Degradation and Stability, 130, 97-102.
Yamagushi, M., Suzuki, K.-I. (2001). Rheological properties and foam processability for blends of linear and crosslinked polyethylenes. Journal of Polymer Science Part B: Polymer Physics, 39(18), 2159-2167.
Zhang, Y., Chen, X., Fang, Z. (2013). Synergistic effects of expandable graphite and ammonium polyphosphate with a new carbon source derived from biomass in flame retardant ABS. Journal of Applied Polymer Science, 128(4), 2424–2432.
Zheng, Z., Liu, Y., Zhang, L., Wang, H. (2016). Synergistic effect of expandable graphite and intumescent flame retardants on the flame retardancy and thermal stability of polypropylene. Journal of Materials Science, 51(12), 5857–5871.
