Copper metal‐organic framework toward flame‐retardant enhancement of thermoplastic polyurethane elastomer composites based on ammonium polyphosphate

Abstract

In this article, copper metal‐organic framework (MOF‐Cu) was synthesized and used as synergism with ammonium polyphosphate (APP) to prepare flame‐retardant thermoplastic polyurethane (TPU) composites. The synergistic flame‐retardant effects between MOF‐Cu and APP in TPU composites were studied by cone calorimeter (CCT), limiting oxygen index tests (LOI), vertical burning tests (UL‐94), smoke density test, etc. The results showed that MOF‐Cu had some flame‐retardant effects on TPU, and APP had good flame retardancy in TPU/APP composites. And, the flame retardancy of TPU/APP was further enhanced when MOF‐Cu was used as synergism with APP. It has been found that the peak heat release rate (pHRR) and total heat release (THR) values of TPU/Cu0.0625 sample were reduced by 26.0% and 1.3% compared with pure TPU, respectively. And the pHRR and THR values of TPU/APP sample were reduced by 70.3% and 15.8% compared with pure TPU. In the case of TPU/APP/Cu0.0625 sample, the pHRR and THR values were furtherly reduced by 19.2% and 63.4% compared with TPU/APP, because of the minor amount of MOF‐Cu. It has been found MOF‐Cu cannot suppress the smoke release and reduce the total smoke release (TSR) value. However, 0.125 wt% MOF‐Cu can make the TSR value of TPU/APP/Cu0.125 sample reduce to 227.8 m2/m2, which was 23.4% lower than that of TPU/APP. The good synergistic flame‐retardant effect between MOF‐Cu and APP was obtained by the catalyzing carbonization process to form the char residue layer with high graphitization and expansion degree.

Synthesis of ZnFe2O4@Mg‐Al‐SDBS LDH composites for regulating heat and fire safety properties of polyurea

“…Combining the above characterization and some references, 53,54 the flame retardant mechanism of ZF@MASL is exhibited in Scheme 2. During the combustion process of Mg‐Al LDH, water vapor and anions will be released, thereby producing porous metal oxides, which can delay polymer combustion.…”

“…Combining the above characterization and some references, 53,54 the flame retardant mechanism of ZF@MASL is exhibited in Scheme 2.…”

Constructing a novel synergistic flame retardant by hybridization of zeolitic imidazolate framework‐67 and graphene oxide for thermoplastic polyurethane

“…Some novel FR such as metal hydroxides, 6 organic phosphorus compounds, 7,8 and even some carbon‐based/silicate nano‐fillers 9 have been developed. Among them, ammonium polyphosphate (APP) is considered an effective FR to many kinds of polymers 10 including TPU 11,12 . The heat and smoke generated in the combustion of TPU were greatly reduced by the addition of 7.0 wt% of APP, but APP cannot eliminate the melt dripping, which can ignite the surroundings.…”

Surface Modification of Ammonium Polyphosphate for Enhancing Flame-Retardant Properties of Thermoplastic Polyurethane

“…However, TPU is flammable, which severely limits its application due to fire-resistance requirements. Therefore, research on improving flame retardancy and reducing the release of toxic gases and smoke of TPU has attracted a lot of attention [ 3 , 4 , 5 ]. In recent decades, many flame-retardant materials have been extensively studied.…”

“…More importantly, the surface of PDA has a large number of functional groups such as amino and hydroxyl groups, which can provide abundant metal-chelating sites [ 18 ]. Cu 2+ -chelated PDA has a strong catalytic carbonization ability [ 5 , 19 ]. More dense carbon layers can be obtained to inhibit the transfer of heat and oxygen to the polymer, thereby effectively improving the flame-retardant properties of the polymer [ 20 ].…”