Yunxin Ai,Zhaoqi Zhu,Weijun Liu,Hanxue Sun,Jiyan Li,Rui Jiao,An Li
The development of high-performance flame-retardant materials with favorable thermal insulation properties is crucial for mitigating fire hazards and energy consumption in applications such as packaging and modern buildings. In this study, flame-retardant microcapsules (VUMF-APP) were synthesized via microencapsulation and electrostatic self-assembly with ammonium polyphosphate (APP) as the core, urea–melamine–formaldehyde (UMF) resin as the shell, and thermoelectric-responsive VO2 (M) as the functional outer layer. These microcapsules were incorporated into epoxy resin (EP) to enhance the composite’s (VUMF–APP–EP) thermal stability, flame retardancy, and intelligent early warning function. The VUMF–APP–EP composite exhibits notable thermal insulation performance with a thermal conductivity of 0.0117 W m–1 K–1. Compared to pristine EP, the composite shows reductions of 46.7% in peak heat release rate (pHRR) and 78.3% in total smoke production (TSP) and achieves a UL-94 V-0 rating, indicating its effective flame-retardant characteristics. Owing to the thermoelectric-responsive property of VO2 (M) decorated onto the microcapsules, the epoxy resin composite demonstrates an intelligent early warning function, triggering alerts before fire ignition while maintaining flame retardancy. This dual functionality contributes to timely fire prevention and the reduction of potential property damage and casualties.
Bin Li,Shouqin Tian,Jiachen Qian,Senwei Wu,Baoshun Liu,Xiujian Zhao
Thermochromic VO 2 -based smart windows are considered as a highly promising building envelope to reduce building energy consumption. However, the inherent unsatisfactory optical performance hindered its practical applications and nanocomposite films are testified to be the most promising strategy addressing this issue, while uniformly dispersing nanoparticles is often a challenge. Herein, a facile in situ method was proposed to directly fabricate highly dispersed VO 2 nanoparticles (HD-VN) on a glass surface from the VOC 2 O 4 ·xH 2 O aqueous solution to achieve the high-optical performance VO 2 film (HD-VN film). The forming mechanism of HD-VN was fully elucidated and HD-VN was generated via the sintering process from the irregular VO 2 particles derived from the decomposition of polyvinyl pyrrolidone (PVP). The HD-VN film showed excellent luminous transmittance ( T lum ) of 72.5% and solar energy modulation efficiency (Δ T sol ) of 10.1%, the former was attributed to the reduced refractive index which led to a reduced reflectance of HD-VN film, and the latter was ascribed to the localized surface plasmon resonance (LSPR) behavior of the HD-VN. The simple and cost-efficient synthesis strategy would promote the application of VO 2 film in energy-efficient glazing, and also shed light on the structures’ design applied to the field of optics, catalysts, and sensors.
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