In this article a preparation method of epoxy resin/glass fabric composites with reduced flammability and smoke emission was presented. For this purpose the two groups of powder-epoxy compositions containing: (1) melamine polyphosphate (MPP) and aluminum diethyl phosphinate (AlDPi); (2) ammonium polyphosphate (APP) and dipentaerythritol (DPE) were used as matrices in six-ply glass fabric reinforced composites. The flame retardants content was 25 wt %. In addition, the 10-15 wt % of zinc borate (ZB) as a smoke reducing agent was added to each compositions. The flame resistant and smoke emission of prepared laminates designed for application in public transport components were evaluated. It was found that with the increase of zinc borate content, the emission of fumes decreased. The lowest maximum of specific optical density (D s max = 312.2), specific optical density in the first 4 minutes of the test [D s (4) = 304.1] and cumulative specific optical densities in the first 4 minutes of the test (VOF 4 = 707.6 min) have been achieved for composite containing 10 wt % of MPP, 15 wt % of AlDPi and 15 wt % of ZB. Furthermore, this composite was characterized by V0 class by UL94 test, limiting oxygen index LOI = 36.8 % and maximum average rate of heat emission MAHRE = 80 kW/m 2 .
In this work the influence of modified bentonites on the process of epoxy crosslinking with triethylenetetramine (TETA) was investigated. Bentonites (BS) modified with quaternary phosphonium (QPS) and ammonium (QAS) salts were used as a nanofiller in the epoxy matrix (EP) in the amounts of 1 and 3 wt %. Gel time of the compositions was investigated using rotational rheometer at 30, 45 and 60 °C and activation energies of the compositions were determined. The storage G' and loss G" moduli crossover criterion was used to determine the nanocomposites gel time variation. On the basis of the obtained results, it was found that the addition of modified aluminosilicates decreased the gel time of epoxy compositions at 30 and 45 °C, while at 60 °C it increased compared to unmodified epoxy resin. The obtained results indicate that the amount of modified aluminosilicate and the type of salt influence the reactivity of epoxy compositions. Among the tested systems, the most reactive was the composition of EP+3%BSQPS1, because the gel time at 30 °C and activation energy decreased by 1500 s and 8 J/mol, respectively, in relation to the unfilled EP resin. A more catalytic effect was observed in the case of bentonites modified with quaternary phosphonium salts, which may be associated with lower phosphorus electronegativity in relation to nitrogen and a lower viscosity of these systems.
Research was carried out on modification of bentonite with the use of a mixer with built-in Parshall's venturi. Aqueous suspensions of bentonite with a concentration of 12 % by weight were used. The advantage of using such an innovative mixer is to achieve much better results of the moving apart layers after modification, which significantly facilities the penetration of polymer chains between them. It should also be noted that the size of the tiles calculated from Scherrer's formula did not decrease after modification with the use of a mixer with built-in Parshall's venturi. Unfortunately, this unfavorable effect was observed for modified bentonites using an anchor mixer. Bentonites modified in this way were used to obtain composites on the epoxy resin matrix Epidian 6 with 3 wt % of their content. Mechanical properties were evaluated and a clear improvement in tensile strength, Young's modulus and notch-free impact strength was found. It was found that the obtained mechanical test results for these composites with the addition of bentonites modified with the use of anchor stirrer are worse in comparison to composites with the addition of bentonite modified with the use of a stirrer with built-in Parshall's venturi.
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