Flame‐retardant synergism of sepiolite and magnesium hydroxide in a linear low‐density polyethylene composite

Abstract

A synergistic effect on flame retardancy, thermal stability, and mechanical properties was found when sepiolite was incorporated into a linear low-density polyethylene (LLDPE)/magnesium hydroxide (MH) composite. Different amounts of sepiolite (up to a maximum concentration of 15 phr) were added to a standard LLDPE/MH formulation, and vinyltriethoxysilane was used as a compatibilizer as well as a crosslinking agent. The thermal stability and the oxidation induction time increased with increasing sepiolite content in the LLDPE composites. Limiting oxygen index (LOI) results indicated an increase in LOI with the addition of sepiolite, and an LOI value of 36.5% was observed with 15 phr sepiolite in the LLDPE/MH formulation. The addition of sepiolite increased the gel content and tensile strength of all samples and lowered the elongation at break. The heat deflection, Vicat softening temperature, and hardness were also improved by the incorporation of sepiolite. This synergistic behavior of sepiolite with MH could be used in halogen-free, flame-retardant LLDPE formulations.

Functional polypropylene composites filled with ultra-fine magnesium hydroxide

“…These phenomena depend primarily on homogeneous filler dispersion. For the material modified with maleic anhydride, PP/10% PP-g-MAH/30% Mg(OH) 2 , the rate reduction from 24.3 mm min -1 to 14.1 mm min -1 and the 42% decrease compared to pure polypropylene are significant compared with literature data [11][12][13]37].…”

“…Mg(OH) 2 silanization using 3-aminopropyltriethoxysilane produced unfavorable results: there was an increase in the Young's modulus but a fall in the values of the other mechanical parameters, including by 40% for elongation at break. Gul et al [13] also observed a dramatic fall in this parameter (from 111.6% to 1.3%). Such unfavourable results are comparable to those obtained here (Table 2) and indicate brittleness.…”

“…Gul et al [13] confirmed synergism among magnesium hydroxide, sepiolite, and polyethylene. Composite thermal stability increased with increasing sepiolite concentration; fire resistance improved by 21.2°C.…”

“…Such unfavourable results are comparable to those obtained here (Table 2) and indicate brittleness. This is obviously a key problem in modifying agent selection [11][12][13][14]18,21].…”

“…TG and DTG analysis determined the mass loss caused by heat (a basis for evaluation of resistance to thermal decomposition), and to compare temperatures at which decomposition began [13,14,18,37]. The TG and DTG curves shown in Figs.…”