Flame Retardant Nano-Structured Fillers from Huntite/Hydromagnesite Minerals

Abstract

In the current study, we propose a simple hydrothermal pathway to synthesize nano-structured Mg(OH)2 after application of thermal decomposition followed by hydration of commercial minerals based on hydromagnesite and huntite. The synthesis of nano-materials is performed without the use of any catalyst. The effect of decomposition temperature on the hydrothermal synthesis of Mg(OH)2 is extensively studied. It is shown that the morphology of resulting structures consists typically of particles ~200 nm in diameter and ~10 nm in thickness. Study of the structure at the molecular level designates the composition and supports the nano-sized characteristics of the produced materials. The associated thermal properties combined with the corresponding optical properties suggest that the material may be used as a flame retardant filler with enhanced transparency. In this concept, the flame retardancy of composite coatings containing the produced nano-sized Mg(OH)2 was examined in terms of limiting oxygen index (LOI), i.e., the minimum concentration of oxygen that just supports flaming combustion.

Novel Hybrid Organic–Inorganic Polymeric Coatings Containing Phosphonium or Acidic Groups for Improving Flame Retardancy of Wood

“…The mineral huntite, H5, was kindly provided by the company Sibelco (Sibelco Hellas SA, Thessaloniki, Greece) and consisted of a huntite/hydromagnesite mixture, 88/12 wt./wt. %; the ratio was calculated by neglecting minor concentrations of other minerals, mostly dolomite [14,19,45]. Ultrapure water was obtained by means of an SG apparatus water purification unit.…”

“…Thus, a higher percentage of H5 is incorporated into the polymer reducing the temperature of the cracking process and releasing a higher percentage of water vapor that dilutes the combustible gases, as well as the flammable acetic acid formed during the decomposition of PVAc [48,49]. Finally, a higher percentage of char is generated through the formation of mainly MgO but also CaO, resulting from the thermal decomposition of huntite, which protects the substrate (polymeric matrix) [45]. The addition of the copolymer P(SSH-co-SSBTPB60) as an additive kept the system's combustibility at low levels with an LOI value of 31%.…”

“…The add P(SSH-co-SSTBHDPB) led to a further increase in LOI values but was not better PVAc/H5 blend. Ecrovin ® LV 340 eco polymer matrix and H5 mixtures were initially prepared parison to previous work [45]. Then, H5 was added to the polymer matrix at a poly ratio of 1/1 to study the effect of the mineral on the combustibility of Ecrovin ® LV The prepared mixtures are presented in Table 8.…”

“…Then, H5 was added to the polymer matrix at a poly ratio of 1/1 to study the effect of the mineral on the combustibility of Ecrovin ® LV The prepared mixtures are presented in Table 8. Ecrovin ® LV 340 eco polymer matrix and H5 mixtures were initially prepared in comparison to previous work [45]. Then, H5 was added to the polymer matrix at a polymer/H5 ratio of 1/1 to study the effect of the mineral on the combustibility of Ecrovin ® LV 340 eco.…”

Facile Ball Milling Preparation of Flame-Retardant Polymer Materials: An Overview

“…The particle size analysis results indicated that the as-prepared products were in the mean size range of 274.5–289.7 nm. The multielement composition (carbon, oxygen, silicon, sulfur, calcium, and potassium) and high decomposition temperature of nano-sized fillers suggest their potential application in the field of flame retardants [ 68 , 69 ]. Besides the biomass raw materials, another important issue in consideration of critical environmental pollution is how to reuse the existing petroleum-based material [ 70 , 71 , 72 ].…”