Investigating Thermal Stability and Flame Retardant Properties of Synthesized Halloysite Nanotubes (HNT)/Ethylene Propylene Diene Monomer (EPDM) Nanocomposites

Abstract

In this work, Halloysite Nanotube (HNT) was synthesized, using a modified method, from kaolin clay. The scanning electron microscopy (SEM) of the synthesized HNT revealed that many of the nanotubes were tubular; however, spherical and semi-spherical, platy and semi rolled structures were also observed. Fire retardant EPDM compounds composed of typical flame retardants (FR), deca-bromo diphenyl oxide (DBDPO), antimony oxide (Sb 2 O 3 ), talc and carbon black were prepared. Three elastomer compounds, with 5, 10 and 20 wt.% of synthesized HNT, and one more compound with 10 wt.% of synthesized HNT and 10 wt.% of conventional flame retardants were prepared and formed by a two roll mill. A TEM micrograph was presented to prove the well dispersion of HNT in polymer matrix. The flammability, thermal stability and tensile strength of the compounds were compared to that of typical fire retarded EPDM. The results showed that the typical flame retardants diminish the tensile strength and elongation at break of EPDM elastomers; in addition, these compounds showed the lowest thermal stability among the typical formulations. The extent of flammability of the compounds was characterized using the cone calorimetry technique. The compound containing 5 wt.% HNT showed the highest tensile strength, the least flammability and the highest thermal stability compared to the other compounds. This was related to the good dispersion and also on the tubular structure of the synthesized nanotubes. The peak of heat release rate (PHRR) and total heat release (THR) as well as the amount of hazardous gas emission for the sample having the highest mechanical response was smaller than those with conventional micro-filler flame retardants.

Preparation and Properties of Ethylene Propylene Diene Rubber/SiO₂/Carbon Nanotubes Composites

“…Moreover, the variation of ∆a indicates the composites become much greener. In addition, the trend of changed ∆b of composites show that the composites become more bluer [9] [10] [17][18][19][20][21].…”

Investigating the Effect of Treated Rice Straw in PLLA/Starch Composite: Mechanical, Thermal, Rheological, and Morphological Study

“…52 Therefore, the samples are expected to show higher crystallinity and T m as compared to the previous samples. Based on the mechanical properties, a high content of lignin and silica together activates the paste effect and for the lower amounts, lignin may act as a plasticizer, as a result, for lower filler content, both T m and H c show a sensible drop in their values compared with the PSRS0 and RS or HWRS-filled samples, although by increasing the filler content silica would actively act as a nucleating agent 53 and somehow reciprocate the lignin plastication effect. The effect of silica is obvious in X t , as the value is increased from 10.91 to 14.32%.…”

Flame retardant epoxy/halloysite nanotubes nanocomposite coatings: Exploring low-concentration threshold for flammability compared to expandable graphite as superior fire retardant

“…HNTs with molecular formula (Al 2 Si 2 O 5 (OH) 4 •nH 2 O) are similar to kaolin, but their hollow structure gives reason to hope that it can be considered as a flame retardant additive [39,41]. Previous studies have uncovered the fact that addition of HNTs at high loading levels (more than 20 wt.%) and/or in combination with conventional flame retardants to polypropylene [42], poly (vinyl alcohol) [43], polyamide 6 [44,45], low-density polyethylene [38,46], ethylene propylene diene monomer [47], and epoxy resin [48,49] could to a large extent improve flame retardancy of polymers. Moreover, recent studies have shown that incorporation of HNTs has a positive effect on thermal degradation of epoxy-based intumescent fire retardant coatings [50].…”