Amount Of Magnesium Hydroxide Research Articles

Bio-mediated MOF-derived core–shell flame retardant: Towards styrene–butadiene–styrene asphalt with enhanced flame safety and pavement performance

In order to improve the flame retardancy of magnesium hydroxide (MH) in styrene– butadiene–styrene (SBS) asphalt, two hierarchically structured bio-based flame retardants (FRs) (MH@SA-MOF and MH@SA-LDH) with MH as the core as well as metal organic framework (MOF) or derived layered double hydroxide (LDH) as the shell, were engineered via an alginate-mediated assembly and etching strategy in this study. The flame retardancy and smoke suppression properties of SBS asphalt were found to be remarkably improved by the addition of the bio-based FRs. In addition, the SBS asphalt with added MH@SA-MOF had a higher limiting oxygen index (LOI) than the SBS asphalt samples to which had been added the same amount of MH or MH@SA-LDH. The peak heat release rate (pHRR) and total heat release (THR) of the bio-based MH@SA-MOF FR asphalt (FRA) was 32.9% and 8.9% lower, respectively, than those of the MH FRA. The MH@SA-MOF and MH@SA-LDH FRs had similar impacts on the flame retardancy of SBS asphalt, but the MH@SA-LDH FR had a stronger smoke suppression effect. In addition, bio-based FRs can enhance the anti-aging and anti-deformation performance of SBS asphalt. Moreover, hierarchical catalytic charring structure was observed, suggesting application prospects in flame-retardant asphalt tunnel pavement for the new FRA designs based on bio-remediation of conventional hydroxide flame retardants.

Studies on the effects of highenergy electron beam irradiation on the Mechanical properties of Magnesium hydroxide filled HDPE/Mg(OH)2/TCA-27 composites

The effect of irradiation electron beam at dose of 150 kGy,on the mechanical properties of
 high density polyethylene (HDPE) mixed with various amounts of magnesium hydroxide (Mg(OH)2) composites as filler have been studied here. It has been found that the highenergy electron beam irradiation has much effect on the mechanical properties of the
 HDPE/Mg(OH)2/TCA-27 composites. The tensile strength and elastic modulus are increased greater than the unirradiated ones. Meanwhile, the increasing content of the Mg(OH)2 in composites. The structure of the SEM of the unirradiated HDPE/ Mg(OH)2/TCA-27 shows poorly mechanical properties of compositeswhich are compared to irradiated ones. The Comparison of properties of composites filled with irradiated and unirradiated Magnesium hydroxide establishes than irradiated of Magnesium hydroxide which imparts better reinforcing properties than unirradiated filler of composites. The properties under consideration are tensile strength, (%) elongation at break, elastic modulus, hardness . Tensile strength isimproved by 6.67% , elastic modulus is improved by 42.86%, while hardness is improved by 0.85%, at ( 0.37 ) volume fraction .

Effect of Magnesium Hydroxide on Flame Retardant Properties for Adhesive Materials by Solution Mixing Process

The objective of this research was to investigate the effect of magnesium hydroxide on the flame retardant properties of adhesive materials. The amount of magnesium hydroxide was varied from 2.5 to 10 phr. The adhesive preparation was performed by means of an aqueous filler dispersion technique. The dispersion of magnesium hydroxide in adhesive was observed by SEM images. The mechanical property of the adhesive joint was conducted by shear stress according to the ASTM D1002 standard. The flame retardant property of adhesives was measured in the horizontal burning testing method. The results revealed that the magnesium hydroxide formed agglomeration. For mechanical test, incorporation of magnesium hydroxide caused a cohesive failure in the substrate. The amount of magnesium hydroxide at 7.5 phr. possessed a maximum adhesive shear stress of 1,140 N. This was due to the magnesium hydroxide acting as reinforcing filler. The flame retardant properties of magnesium hydroxide increased with increasing magnesium hydroxide content. However, only adhesive with 10 phr was lower than 75 mm/min. The results can finally be concluded that the incorporated of magnesium hydroxide at 10.0 phr. remarkable improved the flame retardant properties of adhesive materials.

Influence of magnesium concentration, biomass concentration and pH on flocculation of Chlorella vulgaris

Autoflocculation is a promising low-cost method for harvesting microalgae for bulk biomass production or wastewater treatment. Autoflocculation can be caused by precipitation of calcium or magnesium at high pH. In this study, we investigated the interactive effects of pH, magnesium concentration and microalgal biomass concentration on flocculation of Chlorella vulgaris by magnesium hydroxide. The minimum pH for inducing flocculation was lower when magnesium concentration in the medium is higher. A higher pH and/or higher magnesium concentration are required for flocculation when microalgal biomass concentration is increased. The sludge volume formed during flocculation is highly variable and is influenced mainly by the amount of magnesium hydroxide that precipitates during flocculation. The sludge volume increases with pH and with magnesium concentration in the medium. There is an optimal pH where flocculation efficiency is maximized (>95%) and sludge volume is minimal (1–2% of culture volume). Increasing the pH slightly above this optimum results either in an increase in sludge volume and/or a decrease in flocculation efficiency. We propose that autoflocculation by magnesium hydroxide can be more easily controlled by the dosage of base rather than by targeting a specific pH level.

Heat Release Performance of the Flame Retardant Rigid Polyurethane Insulation Foam

Influence of different flame retardants on the heat release performance of the rigid polyurethane foam (RPF) was studied in this paper. It was found that adding antimony trioxide (ATT) in RPF, heat release rate of RPF was slightly reduced, total heat release was significantly decreased but peak of heat release temperature was decreased. Therefore, ATT was not an excellent flame retardant for RPF. When adding ammonium polyphosphate (APP) in RPF, total heat release of RPF was significantly decreased, ignition temperature was significantly improved and heat release rate was not changed. Melamine polyphosphate (MPOP) could quickly reduce total heat release of RPF so its flame retardant effect was the best. Nitrogen-based flame retardants could reduce peak of heat release rate of RPF. APP, MPOP and nitrogen-based flame retardants were all better flame retardants for RPF. Small amount of magnesium hydroxide (MH) could increase total heat release of RPF.

Mechanical Properties and Flame Retardancy of SEBS-based Composites Filled with Magnesium Hydroxide

The flame-retardancy and mechanical properties of styrene-ethylene/butylene-styrene block copolymer (SEBS) based composites, containing SEBS blended with a paraffinic hydrocarbon extender oil, copolymer polypropylene (PP), and magnesium hydroxide (MH) or silane coupling agent surface-treated magnesium hydroxide (m-MH) were investigated. A maleic anhydride-grafted SEBS (MA-SEBS) was used as a polymer modifier for some composites. As the amount of MH or m-MH increased, the flame-retardancy of composites improved, while the tensile strength and elongation at break decreased, and the melt property of the composites became worse as well. When the oil-filled SEBS (O-SEBS) was partially replaced by MA-SEBS, the tensile strength of the composites increased, and elongation at break decreased. Furthermore replacing O-SEBS with MA-SEBS and treating MH with silane coupling agent (simultaneously) improved the tensile strength of the composites by a large margin. The phase structure of the composites was characterised using scanning electron microscopy (SEM) and this revealed that the particle-matrix interfacial bonding was improved through the addition of MA-SEBS. The stability of the composites was investigated by thermogravimetric analysis (TGA).

Electron beam irradiated HDPE/EVA/Mg(OH)2 composites for flame-retardant electric cables

The mechanical properties and flammability of high-density polyethylene (HDPE)/ethylene vinyl acetate (EVA) mixed with various amounts of magnesium hydroxide (Mg(OH)2) as the filler in composites, irradiated with electron beam at an irradiation dose of 150 kGy, have been studied. It is found that high-energy electron beam irradiation has significant effects on the mechanical properties of the HDPE/EVA/Mg(OH)2 composites. The tensile strength and elastic modulus increased greater than in the unirradiated ones. Meanwhile, with increasing the content of Mg(OH)2 in the composites, the limiting oxygen index (LOI) value increased sharply. The microstructure of the caves of the unirradiated HDPE/EVA/Mg(OH)2 composites show poor interface of composites compared with the irradiated ones, as observed in SEM micrographs.