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Developing advanced performance epoxy (EP) resin with low flammability and light smoke has been an increasing focus of its research. Especially, it is crucial to reduce the emission of smoke and toxic gases generated during the burning of EP, so that it meets the green and safe industrial requirement. Therefore, a 3D NiCo-LDH@PZS hollow dodecahedral structure was designed and synthesized by using the ZIF-67 as both the precursor and an in situ sacrificial template and the amino group-containing polyphosphazene (PZS) as interfacial compatibilizer and flame retardant cooperative. The release behaviors of heat, smoke, and poisonous gases were carefully investigated. More precisely, the EP/NiCo-LDH@PZS4.0 is endowed with a decrease of 30.9% and 11.2% of the peak heat release rate and the total heat release, respectively. The emissions of smoke and poisonous gases including nitric oxides, aromatic compounds, carbonyl compounds, oxycarbide, and hydrocarbons are much less as well. Especially, the maximum release concentrations of HCN of EP/NiCo-LDH4.0 are reduced by 87.8%. With regard to styrene, methane, and ethane, the maximum release concentrations of EP/NiCo-LDH@PZS4.0 are reduced by 85.9%, 90.6%, and 93.1%, respectively. The total yield of CO and CO2and the consumption of O2of EP/NiCo-LDH@PZS4.0 are also reduced by 64.5%, 32.4%, and 33.6%. The fractional effective dose, an index of toxicity smoke, of EP/NiCo-LDH@PZS4.0 is reduced by 20.4%. The DMA tests were performed to study the mechanical properties of EP composites, and the storage modulus and Tg of EP composites are increased with the incorporation of NiCo-LDH@PZS. The possible mechanism of flame retardant was proposed based on the analysis of the condensed and gas phases of EP composites.

It is still a big challenge to prepare polymer/layered double hydroxide (LDH) composites with high performance, due to the strong agglomeration tendency of LDHs in the polymeric matrix. In this study, to avoid the agglomerated situation, the orientated LDH nanosheets were vertically grown on a ramie fabric surface, which was then embedded in unsaturated polyester resin (UPR) through the combination method of hand lay-up and vacuum bag. Due to the increased contact area and the restricted interfacial slip in the in-plane direction, the hierarchically LDH-functionalized ramie fabrics (denoted as Textile@LDH) significantly enhanced the mechanical performance of UPR composites. Then, the phosphorus- and silicon-containing coating (PSi) was used for the further improvement of the interfacial adhesion. The tensile strength of UPR/Textile@LDH@PSi composites increased by 121.67%, compared to that of neat UPR. The reinforcement mechanism was studied through analyzing the surface nano/microstructure and wetting properties of the raw and modified textiles, as well as the interfacial interaction between the ramie fabrics and UPR. Meanwhile, the thermal stability, thermal conductivity, and flame-retardant performance of ramie-reinforced UPR composites were improved. Particularly, as-prepared hierarchical Textile@LDH@PSi inhibited the heat release during the combustion process of fabric-reinforced UPR composites, and the peak heat release rate and total heat release values decreased by 36.56 and 47.57%, respectively, compared with the neat UPR/Textile composites. The suppression mechanism was further explored by analyzing the microstructure and chemical compositions of char residues. This research paved a feasible solution to improve the poor dispersion of LDHs in polymers and prepared the high-performance UPR composites with multifunctional applications.

The poly(ethylene oxide) solid polymer electrolyte (PEO SPE) has recently received much attention, however, the organic components in the SPE are still flammable. In this paper, we find that the high efficiency halogen-free aluminum (Al) diethyl hypophosphite flame retardant (ADP) is effective in reducing the flammability of PEO SPE. The SEI layer containing Al and phosphorus (P) inhibits the growth of lithium dendrite and enhances the cycle life of the battery. The capacity of a LiFePO4/SPE/Li battery containing ADP is still 123.2 mAh g–1at 1.0 C and the Coulombic efficiency is as high as 99.95% after 1000 cycles (60 °C). At the same time, Al, P-rich SEI can inhibit the growth of lithium dendrite and the cycle stability of the battery is further enhanced.