Facile Construction of Polypyrrole Microencapsulated Melamine-Coated Ammonium Polyphosphate to Simultaneously Reduce Flammability and Smoke Release of Epoxy Resin

Abstract

A unique mono-component intumescent flame retardant, named PPy-MAPP, of which melamine-coated ammonium polyphosphate (MAPP) was microencapsulated by polypyrrole (PPy), was synthesized and carefully characterized. The obtained PPy-MAPP was applied to epoxy resin (EP) for obtaining flame-retarded EP composites. The results show that PPy-MAPP imparts better flame retardancy and smoke suppression properties to EP compared to the same addition of MAPP. The EP composite with 15 wt% PPy-MAPP easily passes the UL94 V-0 rating and achieves an LOI value of 42.4%, accompanied by a 61.9% reduction in total heat release (THR) and a 73.9% reduction in total smoke production (TSP) when compared with pure EP. The char residue analysis shows that PPy-MAPP can promote a generation of more phosphorus-rich structures in the condensed phase that improve the integrity and intumescence of char against fire. The mechanical test indicates that PPy-MAPP has a less negative effect on the tensile strength and elastic modulus of epoxy resin due to the good compatibility between PPy-MAPP and the EP matrix, as supported by differential scanning calorimetry (DSC) analyses. In this paper, these attractive features of PPy-MAPP provide a new strategy to prepare satisfactory flame retardant and super flame retarding EP composites.

A facile strategy to construct multifunctional microencapsulated urea ammonium polyphosphate for epoxy resins towards satisfied fire safety, thermal stability and compatibility

“…In addition, the FTIR spectra shows that the characteristic peak corresponding to the NH 3 + structure of EP/10PPy‐UAPP at 1506 cm −1 disappears at 400°C, indicating that the group has been completely decomposed. Moreover, the CH 3 located at 2964 cm −1 and CH 2  groups located at 2869 cm −1 gradually disappear, while the absorption peak at 1608 cm −1 becomes wider, implying the formation of CC group 37 . When the temperature increases to 250 and 350°C, the PNC groups are found at 1084 and 754 cm −1 , respectively 24 .…”

“…Moreover, the CH 3 located at 2964 cm À1 and CH 2 groups located at 2869 cm À1 gradually disappear, while the absorption peak at 1608 cm À1 becomes wider, implying the formation of C C group. 37 When the temperature increases to 250 and 350 C, the P N C groups are found at 1084 and 754 cm À1 , respectively. 24 Besides, a new peak of P O C group appears at 998 cm À1 when the temperature reaches above 400 C, and the carbonized network structures such as aromatics and polyaromatics are observed at 1389 cm À1 in the later stage of pyrolysis.…”

Preparation of DOPO‐derived magnesium phosphate whisker and its synergistic effect with ammonium polyphosphate on the flame retardancy and mechanical property of epoxy resin

“…This result reflects the poor compatibility of APP with EP. 71 However, when DPM-H was used, the mechanical properties of the prepared flame-retardant EPs (EPDA-1 to EPDA-4) were promoted clearly. When the content of DPM-H increased from 0% in EPDA-0 to 1.0% in EPDA-2, the tensile strength and impact strength increased from the 37.8 MPa and 4.6 kJ m À2 of EPDA-0 to the 60.0 MPa and 11.7 kJ m À2 of EPDA-2.…”

Achieving superior fire safety for TPU 3D‐printed workpiece with EP/PBz/PDMS coating

“…It can be seen that TPU-PBEM 0 and TPU-PBEM 30 show the same absorption peak at 1636 cm À1 for the C C group of benzene ring. 38 In the spectrum of TPU-PBEM 0 , the absorption peaks appearing at 1200 cm À1 and 1089 cm À1 are caused by the C H bond 39 and the P O C group 40 of the aromatic compound, respectively. As for TPU-PBEM 30 , the peaks at 1261 cm À1 , 798 cm À1 , 1183 cm À1 and 1020 cm À1 were attributed to P─O 41 and Si─O 42 bonds, respectively.…”