Engineering MXene surface with POSS for reducing fire hazards of polystyrene with enhanced thermal stability

Due to the energy‐saving demands in chemical industries and building fields, thermal isolation materials (TIMs) are widely used. The general exploitation of combustible TIMs calls for timely fire alerts as well as flame‐retardant modifications. This work provides a novel paradigm to address the issues simultaneously by preparing a multifunctional aerogel via a facile and environmentally friendly freeze‐drying method. With the doping of ammonium polyphosphate and graphene oxide (GO), cellulose nanofiber‐based aerogel exhibits excellent thermal‐isolating as well as flame‐retardant properties. The composite aerogel displays flameless pyrolysis as well as increased residue char. A fire‐warning detector is designed to reliably monitor the early fire. Based on the flame‐induced electrical resistance transformation characteristic of GO, it endows the composite aerogel with an ultra‐fast fire‐response time of ~2.6 s and a durable alarm signal. The flame‐retardant and fire‐alarm mechanisms are concluded. Overall, these results suggest that this composite aerogel has an enticing prospect in chemical industries and high‐rise buildings, which may lay the foundation for designing multifunctional TIMs. The modified aerogel broadens its application territory by intrinsic fire‐alarm characteristics, which covers the deficiency of delaying reaction as well as restricted application scenarios in traditional fire detectors.

Section: Introductionmentioning

confidence: 99%

Thermally induced fire early warning aerogel with efficient thermal isolation and flame‐retardant properties

Yuan

2021

“…The FTIR spectrum of CNF‐MMT‐GO‐30% (Figure 11B) before combustion shows the characteristic peaks at 3381, 1721, 1425, and 1060 cm −1 , corresponding to the vibrations of hydroxyl and carbonyl groups and the deformation vibration of CH and COH, respectively 57‐60 . In the FTIR spectrum of CNF‐MMT‐GO‐30% after combustion, the characteristic bands of hydroxyl groups, carbonyl groups, and CH weaken or disappear.…”

Section: Resultsmentioning

confidence: 99%

Flame‐retardant cellulose nanofiber aerogel modified with graphene oxide and sodium montmorillonite and its fire‐alarm application

Zuo

Yuan

2021

Thermal insulation materials (TIMs) are widely used to realize energy conservation in buildings, but most of the commonly used organic TIMs are flammable. A novel biomass‐based aerogel is produced by an environmentally friendly vacuum freeze‐drying method, and a facile approach is proposed to improve the flame‐retardant performance of cellulose nanofiber (CNF) aerogels by modifying them with graphene oxide (GO) and montmorillonite (MMT). GO and MMT form a barrier that blocks the contact between the composite aerogel and the external oxygen, achieving the flame‐retardation effect. Notably, based on the high‐temperature thermal reduction characteristic of GO, a fire‐alarm system that can provide an ultrasensitive and reliable fire‐warning signal is designed. A fire alarm of CNF‐MMT‐GO‐50% can be triggered in approximately 1.9 seconds and lasts for more than 137.0 seconds when the aerogels are attacked by fire. This work helps to develop advanced TIMs to solve the shortcomings of traditional organic insulation materials and supplies a newfangled idea for the design of fire‐alarm sensors, showing promising applications in building insulation, firefighting, and chemical industry.

“…It was because the decomposition of MVDOS generated phosphorus‐containing polymers on the surface of the matrix, as confirmed by the TG, SEM, and XPS results. The thermally stable phosphorus‐containing polymers acted as a physical barrier preventing the escape of combustible volatiles for feeding the fire, which inhibited the degradation of underlying martix 45,46 . In the meanwhile, the intumescent and dense protective char layer generated by the catalytic charring effect of MVDOS could also suppress the transfer of oxygen and heat to the interior of the polymer 30,47,48 .…”

Section: Resultsmentioning

confidence: 99%

A novel P‐S‐Si‐based cage‐structural monomer for flame‐retardant modification of unsaturated polyester resin

Zhang

Song

et al. 2020

Currently, the issue of improving the flame‐retardant performance of unsaturated polyester resin (UPR) has drawn a lot of attention. In this study, methyl vinyl di (1‐thio‐2,6,7‐trioxal‐1‐phosphabicyclo [2.2] octane‐4‐methoxy) silane (MVDOS) with P‐N‐Si‐based cage unit was synthesized, and it was utilized as a reactive flame‐retardant monomer to modify UPR. The UPR/MVDOS composites were prepared by introducing different ratios of MVDOS into UPR via the reaction of crosslink. The efficiency of the resulted composites was investigated by using the limiting oxygen index (LOI), vertical burning test, and cone calorimeter test. The results showed that the composites reached the V‐0 rate without dripping, and the LOI value was 29.1% when the content of MVDOS was as low as 18 wt%. Cone calorimeter tests revealed the peak of heat release and CO production of UPR/MVDOS‐18 were 238.2 KW/m2 and 0.0167 g/s, which were respectively lower than the ones of neat UPR. The introduction of MVDOS also increased the stability of UPR composites. Furthermore, the scattering electron microscopy, laser Raman spectroscopy, and X‐ray photoelectron spectroscopy studies revealed that the incorporation of MVDOS stimulated the UPR matrix to generate char layer with increased graphitization degree, which provided a good barrier to prevent heat and oxygen from being transferred and then protected the materials inside from further burning. This research provides a new way to obtain flame‐retardant UPR composites with high performance.