Synergistic flame‐retardant effect of DOPO‐based derivative and organo‐montmorillonite on glass‐fiber‐reinforced polyamide 6 T

Abstract

Herein, a bridged 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) derivative (PN‐DOPO) in combination with organ‐montmorillonite (OMMT) was used to improve the flame retardancy and mechanical properties of glass‐fiber‐reinforced polyamide 6 T (GFPA6T). The flame retardancy and thermal stabilities of the cured GFPA6T composites were investigated using limiting oxygen index, vertical burning (UL‐94) test, cone calorimeter test, and thermogravimetric analysis (TGA). The morphological analysis and chemical composition of the char residues after cone calorimeter tests were characterized via scanning electron microscopy and energy dispersive spectrometry. The results indicate that 2 wt% OMMT combined with 13 wt% PN‐DOPO in GFPA6T achieved a V‐0 rating in UL‐94 test. The peak heat release rate and total smoke release remarkably decreased with the incorporation of OMMT as compared to those of GFPA6T/15 wt% PN‐DOPO. The TGA results show that the thermal stability and residual mass of the samples effectively increased with the increase in OMMT content. The morphological analysis and composition structure of the residues demonstrate that a small amount of OMMT could help form a more thermally stable and compact char layer during combustion. Also, with the incorporation of OMMT, the layers consisted of more carbon‐silicon and aluminum phosphate char in the condensed phase. Furthermore, GFPA6T/PN‐DOPO/OMMT composites exhibited excellent mechanical properties in terms of flexural modulus, flexural strength, and impact strength than the GFPA6T/PN‐DOPO system. The combination of PN‐DOPO and OMMT has improved the flame retardancy and smoke suppression of GFPA6T without compromising the mechanical properties.

Synergistic Effects of DOPO-Based Derivative and Organo-Montmorillonite on Flame Retardancy, Thermal Stability and Mechanical Properties of Polypropylene

“…The addition of DOPO-based FRs reduce the initial thermal stability of the polymer matrix and slightly promotes char formation [17,18]. These results are in agreement with other similar reported conclusions [22,31,35]. After adding OMMT into PP, the peak temperatures of mass loss were reduced to 432.7 °C, which was mainly due to the decomposition of organoclay [20,40].…”

“…Compared with the PP/PN-DOPO sample, the T 5% and T max increased by 10.5 • C and 9.0 • C, respectively, and the residues increased to 2.2 wt%. The reason for the increment in thermal stability and char residue can be attributed to a synergistic effect on the formation of protective barrier layers or the thermal interaction between the flame retardants and the polymer matrix [31,43].…”

“…Based on our previous reports, a novel phenethyl-bridged DOPO derivative (PN-DOPO) was prepared. The effects of PN-DOPO on the flame-retardant and thermal properties of the polymeric matrix, such as polyamide, epoxy resins and polylactide, were examined [17,[31][32][33][34][35]. The results showed that PN-DOPO could be a good candidate to improve the flame retardancy and thermal stability of the polymer matrix.…”

Forced Vibration Analysis of Composite Beams Reinforced by Carbon Nanotubes

“…where i indicates the number of polynomials involved in the admissible functions. After substituting Equation (7) into Equation ( 4), and then using the Lagrange's equation, the following equation can be derived:…”

“…The main advantages of composite materials are excellent strength-to-weight and stiffness-to-weight ratios. The fibrous composites, consisting of carbon, glass, aramid, and basalt fibers, have a wide range of applications in many modern engineering and industries, such as civil, automotive, bicycle, mechanical, defense, marine, aviation, and aerospace [1][2][3][4][5][6][7][8][9].…”