Properties of nano Mg(OH)2-microencapsulated red phosphorus/ ethylene-vinyl acetate copolymer flame-retardant composite

作者：Liu, Jichun^*; Li, Hang; He, Yunpeng; Pan, Bingli; Luo, Jie; Liu, Hongyu

来源：Acta Materiae Compositae Sinica, 2019, 36(11): 2530-2540.

DOI：10.13801/j.cnki.fhclxb.20190326.002

• Ethylene vinyl acetate copolymer
• Flame retardancy
• Halogen-free flame retardant
• Limiting Oxygen Index
• Processing properties
• Rheological analysis
• Smoke suppression
• Vertical burning tests

Using micro Mg(OH)2(mMg(OH)2), nano Mg(OH)2(nMg(OH)2) and microencapsulated red phosphorus (MRP) as the halogen-free flame retardants and ethylene-vinyl acetate copolymer (EVA) as the polymer matrix, a series of Mg(OH)2-MRP/EVA flame-retardant composites with different loadings of flame retardant were prepared by melt-compounding. The flame retardancy, mechanical and processing properties of the Mg(OH)2-MRP/EVA composites were investigated by limiting oxygen index, vertical burning test, cone calorimetry, thermal analysis, SEM, tensile test and rheological analysis. The results indicate that both flame retardancy and smoke suppression of the nMg(OH)2/EVA composite are better than that of the mMg(OH)2/EVA composite at the same loading of Mg(OH)2flame retardant. However, the UL-94 rating of nMg(OH)2/EVA and mMg(OH)2/EVA composites can not reach V-0 rating when the Mg(OH)2loading is less than 60wt%. The flame retardant efficiency of Mg(OH)2is low by itself and there is remarkable synergism between nMg(OH)2and MRP on the flame retardancy of EVA. The loading of Mg(OH)2can be reduced considerably when nMg(OH)2and MRP are combined at proper ratio. Comparing with nMg(OH)2/EVA composite, the nMg(OH)2-MRP/EVA composite can produce a continuous and compact char residue layer on its surface, which serves as a barrier against fire and increases fire retardancy. The thermal degradation of nMg(OH)2has crucial influence on the fire behavior of the nMg(OH)2-MRP/EVA composite. When nMg(OH)2is pre-pyrolyzed and added to the MRP/EVA composite, both flame retardancy and smoke suppression of the obtained nMg(OH)2-MRP/EVA composite decline sharply. When the mass ratio of nMg(OH)2:MRP:EVA is 40:10:100, the obtained nMg(OH)2-MRP/EVA composite shows excellent flame retardant, mechanical and processing properties simultaneously, which can meet the demand of practical applications.

• 出版日期2019
• 单位河南大学