Synergistic Flame Retardant Effect of SiO2in LLDPE/EVA/ATH Blends

Abstract

SiO₂ has long been recognized as an inert diluent and usually used as an enhancing agent in thermoplastic polymers. Few reports are presented about its use as additive flame retardant. In this article, the flame retardant synergistic effect of SiO₂ with aluminum hydroxide (ATH) on linear low density polyethylene and ethylene-vinyl acetate (LLDPE/EVA) composites in the presence of a new compatibilizer, polyethylene (PE) grafted by fluoropolysiloxane (FS), prepared to improve the compatibility between polymers (LLDPE/EVA) and inorganic fillers (ATH and SiO₂), is investigated by means of limited oxygen index (LOI), cone calorimeter (CONE) and thermogravimetric analysis (TGA). The results show that the addition of SiO₂apparently increases the LOI value and decreases the heat release rate (HRR), mass loss rate (MLR), and specific extinction area (SEA). The TGA data shows further evidence that the synergistic mechanism of SiO₂ with ATH is mainly due to the physical process in the condensed phase leading to the formation of a more stable and compact barrier, which efficiently prevents the heat and mass transfer in fire. The good mechanical properties of the flame retardant materials implies the improved compatibility by the newly prepared compatibilizer.

Keywords

SiO2 aluminumhydroxide LLDPE EVA flameretardant

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References

Lu, S.Y. and Hamerton, I . (2002). Recent Developments in the Chemistry of Halogen-free Flame Retardant Polymers , Progress in Polymer Science, 27: 1661–1712 .

Sen, A.K. and Mukheriee, B . (1991). Preparation and Characterization of Low-Halogen and Nonhalogen Fire-Resistant of Low-Halogen and nonhalogen Fire-Resistant Low-Smoke(Frls) Cable Sheathing Compound From Blends of Functionalized Polyolefins and PVC , J. Appl. Polym. Sci., 43: 1673–1684 .

Riva, A. , Camino, G. and Fomperie, L . (2003). Fire Retardant Mechanism in Intumescent Ethylene Vinyl Acetate Compositions , Poly. Deg. Stab., 82: 341–346 .

Ray, L. and Khastgir, D . (1994). Low-Density Polyethylene(LDPE) and Ethylene-Vinyl Acetate (EVA) Copolymer Blends as Cable Insulates , Plast. Rubber. Compos. Process. Appl., 22: 37–45 .

Castellani , et al. (2002). Cables with a Halogen-Free Recyclable Coating Comprising Polypropylene and an Ethylene Copolymer having High Elastic Recovery, United States Patent 6,372,344.

Scelza, C . (2003). Self-Extinguishing Cable and Fire Retardant Composition Used Therein, United States Patent Application 20030164483.

Li, Z. and Qu, B . (2003). Flammability Characterization and Synergistic Effects of Expandable Graphite with Magnesium Hydroxide in Halogen-Free Flame-Retardant EVA Blends , Polymer Degradation and Stability, 81: 401–408 .

Hornsby, P.R. , Cusack, P.A. and Cross, M . (2003). Zinc Hydroxystannate-Coated Metal Hydroxide Fire Retardants: Fire Performance and Substrate-Coating Interactions , Journal of Materials Science, 38: 2893–2899 .

Cross, M.S. , Cusack, P.A. and Hornsby, P.R . (2003). Effects of Tin Additives on the Flammability and Smoke Emission Characteristics of Halogen-Free Ethylene-Vinyl Acetate Copolymer , Polymer Degradation and Stability, 79: 309–318 .

10.

Carpentier, F. , Bourbigot, S. and Le Bras (2000). Charring of Fire Retarded Ethylene Vinyl Acetate Copolymer-Magnesium Hydroxide/Zinc Borate Formulations , Polymer Degradation and Stability, 69: 83–92 .

11.

Durin, F.A. , Ferry, L. , Lopez, C.J. and Crespy, A . (2000). Magnesium Hydroxide/Zinc Borate/Talc Compositions as Flame-Retardants in EVA Copolymer , Polymer International, 49: 1101–1105 .

12.

Wei, P. , Hao, J. , Du, J. , Han, Z. and Wang, J . (2003). An Investigation on Synergism of an Intumescent Flame Retardant Based on Silica and Alumina , Journal of Fire Science, 21: 17–28 .

13.

Gaylord, N.G. and Mishra, M.K . (1983). Nondegradative Reactive of Maleic-Anhydride and Molten Polypropylene in the Presence of Peroxides , Journal of Polymer Science Part C-Polymer Letters, 21: 23–30 .

14.

Lee, S. , Rengarajan, R. and Parameswaran, V.R . (1990). Solid-Phase Graft-Copolymerization-Effect of Interfacial Agent , Journal of Applied Polymer Science, 41: 1891–1894 .

15.

Yeong, T.S. and Chih, M.L . (1999). Silane Grafting Reactions of LDPE, HDPE, and LLDPE , Journal of Applied Polymer Science, 74: 3404–3411 .

16.

Brannock, G.R. , Barlow, J.W. and Paul, D.R . (1991). Blends of Styrene of Styrene Maleic-Blends of Styrene Maleic-Anhydride Copolymers with Polymethacrylates , Journal of Polymer Science Part B – Polymer Physics, 29: 413–429 .

17.

Chiang, W.Y. and Ku, Y.N . (2002). The Effect of Maleic Anhydride Grafting on the Flame Retardation of Plasma Pretreated Polyethylene , Polymer Degradation and Stability, 76: 281–290 .

18.

Fu, M. and Qu, B . (2004). Synergistic Flame Retardant Mechanism of Fumed Silica in Ethylene-Vinyl Acetate/Magnesium Hydroxide Blends , Polymer Degradation and Stability, 85: 633–639 .