Preparation of TPU/GO/Mg‐Al LDHs Hybrid Material With Enhancing Flame Retardancy and Smoke Suppression Performance

Abstract

Flammability of Thermoplastic polyurethane (TPU) limits its application in automotive, wires and cables, sports and textile coatings. Endowing TPU with simultaneously improved flame retardancy and smoke-suppressant will be highly beneficial. Herein, a novel green and efficient condensed phase GO/ MgÀ Al layered double hydroxides (LDHs) flame retardant for TPU was synthesized by the co-precipitation of Mg 2 + and Al 3 + and assembled with graphene oxide (GO) by electrostatic interaction. The unique two-dimensional layered structure of GO/LDHs has a large specific surface area, which can form a dense and uniform char layer during the combustion process, thus hindering mass and heat transfer between gaseous and condensed phases. The XRD, TEM, SEM and EDS results showed that MgÀ Al LDHs and GO/LDHs were successfully synthesized. The thermal, flame retarding and smoke suppression properties of TPU/GO/MgÀ Al LDHs were determinated by UL-94, limiting oxygen index (LOI), cone calorimeter (CCT) and smoke density (SDT). UL-94 testing results showed that all the TPU/GO/MgÀ Al LDHs samples had a vertical combustion rating of V-0. Compared with pure TPU (19.1 � 0.2 %), the LOI value of all TPU/GO/MgÀ Al LDHs composites are above 27 %. CCT results showed TGAL3 sample displayed the lowest peaks of heat release rate (pHRR) value of 142.9 � 9.3 Kw m À 2 . The total heat release (THR) value of TGAL5 is almost 70 % lower than that of pure TPU. In addition, compared to pure TPU, GO/MgÀ Al LDHs materials has excellent performance in smoke suppression. The digital photos and Raman spectra of char residue demonstrated that TPU/GO/MgÀ Al LDHs materials has a denser carbon layer after combustion. Apart from flame retarding and smoke suppression, the mechanical properties of TPU/GO/MgÀ Al LDHs can maintain more than 80 % of the original TPU after addition of GO/LDHs. These results indicates that GO/LDHs composites is a kind of two-dimensional layered material with unique structure and excellent flame retardant and smoke suppression.

Functionalized Zr‐MOFs for Enhancing Flame Retardancy and Smoke Suppression Performance on TPU

“…However, acting as interior decoration materials, TPU should be modified owing to the risk of fire and releasing toxic gases during combustion [1–2] . Therefore, both flame retardant and smoke suppression performance should be concerned through improving flame retardant TPU [3] . MOFs are considered an effective flame retardant and smoke suppressant material due to their unique structure and adsorption properties [4–6] .…”

“…[1][2] Therefore, both flame retardant and smoke suppression performance should be concerned through improving flame retardant TPU. [3] MOFs are considered an effective flame retardant and smoke suppressant material due to their unique structure and adsorption properties. [4][5][6] In the process of thermal decomposition, most MOFs materials can generate metal oxides and some nonflammable gases.…”

A multi‐element flame retardant for rail transit to improve the flame retardant performance of epoxy resin while reducing smoke density

“…According to the literature, the smoke suppression mechanism is mainly attributed to the gas phase and condensed phase, and the gas phase mainly promotes the full combustion of materials by inducing highly reactive free radicals to achieve the smoke suppression effect 13,14 . The condensed phase mainly reduces the volatilization of combustible molecules by promoting the formation of a heat‐insulating carbon layer, while the introduction of flame retardants may block the free radical chain reaction in the gas phase to make it inadequate for combustion, so the improvement of flame retardants does not necessarily reduce the smoke density 15–18 …”

“…13,14 The condensed phase mainly reduces the volatilization of combustible molecules by promoting the formation of a heat-insulating carbon layer, while the introduction of flame retardants may block the free radical chain reaction in the gas phase to make it inadequate for combustion, so the improvement of flame retardants does not necessarily reduce the smoke density. [15][16][17][18] In this study, a flame retardant (DTBD) containing a P/N/Si structure was obtained by esterification and addition of 3,5-diaminobenzoic acid, benzaldehyde, triphenylsilyl alcohol, and DOPO. DTBD was added to Bisphenol F diglycidyl ether (DGEBF) resin to synthesize flame retardant epoxy resin, and three different ratios of DTBD were designed to explore the effects of flame retardant DTBD on the flame retardant, smoke suppression, and mechanical properties of epoxy resin, and the flame retardant mechanism of DTBD in the two phases was analyzed.…”