Flame‐retardant poly (ethylene terephthalate) enabled by a novel melamine polyphosphate nanowire

Abstract

A novel strategy was developed for the preparation of melamine polyphosphate (MPP) nanowires to achieve a superior flame‐retardant poly (ethylene terephthalate) (PET). Thanks to the well‐designed nanostructure, the prepared MPP nanowires exhibited great thermal stability and flame retardance. Herein with incorporation of only 1‐wt% MPP nanowires (PET/FR1.0 nanocomposite), the limiting oxygen index (LOI) value was dramatically increased to 29.4% from 20.5%, showing self‐extinguishing behavior. Moreover, PET/FR1.0 nanocomposite passed V‐0 UL‐94 rating in the vertical combustion test. However, PET containing 5‐wt% commercial MPP powder (PET/FRC5.0) only showed a LOI of 27.9% and ignited the absorbent cotton with flammable melt‐droplets. Cone results also presented that introducing 1‐wt% MPP nanowires brought about a crucial decrease in fire hazard of PET, for instance, 11.1% and 7.7% maximum reduction in heat release rate and total heat release, respectively. Thermogravimetric analysis/infrared spectrometry (TG‐FTIR) result indicated that the main pyrolysis volatiles generated from PET degradation including benzoic acid, aromatic compounds, and carbon dioxide were apparently suppressed after introducing MPP nanowires into PET matrixes, suggesting the outstanding obstructing effect of graphited char residue formed in the combustion. This enhanced flame retardancy rooting in addition of MPP nanowires can be attributed to the combined dilution effect in gaseous phase and catalytic carbonization effect in condensed phase.

Glass fiber reinforced PET modified by few‐layer black phosphorus

“…This may be due to the absorption ability of BPs (befit for the absorption of small molecules as layered nanomaterial) and its catalytic ability of char formation (dense carbon layer to block the generated smoke). Moreover, the intensities of flammable compounds (e.g., aromatic compounds) were also decreased, which would benefit the decrement of heat release during the combustion process 35 . This result was consistent with those obtained by CCT, and further verified the high performance of BPs as flame retardant and its superiority compared with RP.…”

“…Besides the investigation of the condensed phase, TG‐FTIR was used to study the gas phase product of PET/GF, PET/GF@RP‐2.7, and PET/GF@BP‐2.7 during combustion (Figure 6). Three representative bands were used to represent the evolved gas phase products: 1510 cm −1 was assigned to aromatic compounds, 1760 cm −1 corresponded to benzoic acid, 2360 cm −1 was due to carbon dioxide 9,34,35 . As expected, the maximum intensity of these bands decreased after modification.…”

Morphology-Controlled Synthesis of Polyphosphazene-Based Micro- and Nano-Materials and Their Application as Flame Retardants

“…The initial degradation temperatures of the PET/PZS composites were all reduced relative to PET owing to the addition of the flame retardant material, with PET/PZS_SP exhibiting the lowest T 5 of 366 °C. The flame retardant catalyzed and accelerated the degradation of PET, which is consistent with previously reported results in the literature [ 17 , 18 ]. The maximum degradation rate (T max ) did not significantly change except for PET/PZS_SP, which was lower than that of PET.…”

Functionalization of PET with Phosphazene Grafted Graphene Oxide for Synthesis, Flammability, and Mechanism

“…The resulting data are shown in Table 6 and Figure 10 and Figure 11 . The main pyrolysis products of neat PET are 34.1% Benzoic acid, 8.7% Terephthalic acid, 8.5% Methyl benzoate, 7.6% benzene, 7.2% Bibenzene, 6.3%p-ethylbenzoic acid, 5.1% Styrene, 5.0% p-Acetylacetophenone and 3.9% Acetophenone [ 40 ]. Based on the results, the proposed pyrolysis process of PET is shown in Figure 10 .…”