Effect of Functionalized Graphene Oxide with Hyper-Branched Flame Retardant on Flammability and Thermal Stability of Cross-Linked Polyethylene

In this work, GO was functionalized by a hyper-branched flame retardant, which was synthesized by the reaction of N-aminoethyl piperazine and di(acryloyloxyethyl)methylphosphonate. Subsequently, the resultant functionalized GO (FGO) was incorporated into the cross-linked polyethylene (XLPE) to enhance the flame retardancy of the matrix. Transmission electron spectroscopy images indicated that FGO exhibited uniform dispersion in XLPE matrix and strong adhesion with the matrix by cross-linking, which improved barrier effect due to reduced heat release and the free radical transfer between the matrix and graphene nanosheets. The incorporation of FGO into XLPE matrix endowed polymer composites with flame retardancy and thermal stability. In addition, the homogeneous dispersion of functionalized GO with a hyper-branched flame retardant in the polymer matrix improved the antioxidation and mechanical properties of XLPE-FGO nanocomposites compared to the XLPE-GO samples, as demonstrated through the oxidative induction temperature and time test, oven aging test and mechanical test. © 2014 American Chemical Society

FedMLSecurity: A Benchmark for Attacks and Defenses in Federated Learning and LLMs

This paper introduces FedMLSecurity, a benchmark that simulates adversarial attacks and corresponding defense mechanisms in Federated Learning (FL). As an integral module of the open-sourced library FedML that facilitates FL algorithm development and performance comparison, FedMLSecurity enhances the security assessment capacity of FedML. FedMLSecurity comprises two principal components: FedMLAttacker, which simulates attacks injected into FL training, and FedMLDefender, which emulates defensive strategies designed to mitigate the impacts of the attacks. FedMLSecurity is open-sourced 1 and is customizable to a wide range of machine learning models (e.g., Logistic Regression, ResNet, GAN, etc.) and federated optimizers (e.g., FedAVG, FedOPT, FedNOVA, etc.). Experimental evaluations in this paper also demonstrate the ease of application of FedMLSecurity to Large Language Models (LLMs), further reinforcing its versatility and practical utility in various scenarios

Recent progress in black phosphorus nanosheets for improving the fire safety of polymer nanocomposites

The application of black phosphorus (BP) nanosheets to improving the fire safety of polymers has been intensively explored in recent years. The phosphorus-rich construction, inherent layered structure, and ease of surface modification contribute to the highly efficient flame-retardant performance of BP nanosheets. Reported results confirmed that BP nanosheets and BP-based hybrids could reduce the release of heat, suppress fire spreading, and reduce the emission of smoke and toxic gases during the combustion of polymers. However, the poor air and moisture stability, severe synthesis conditions, and difficulty to scale up limit their wide application. Up to date, there is no review about BP-based flame retardants for improving the fire safety of polymer nanocomposites. In this review, we summarize the proposed, preparation approaches, surface modification methods and improved air stability, and flame-retardant mechanisms of BP nanosheets and flame-retardant BP nanosheets/polymer composites. The fire safety of polymer nanocomposites is discussed to specifically illustrate the functions of BP nanosheets. Lastly, the limitations and the outlook of using BP nanosheets as flame retardants are presented.The work was financially supported by the National Natural Science Foundation of China (51874266). This study was also supported under the RIE2020 Industry Alignment Fund – Industry Collaboration Projects (IAF-ICP) Funding Initiative

Water Quality and Microbial Community Changes in an Urban River after Micro-Nano Bubble Technology in Situ Treatment

Currently, black-odor river has received great attention in China. In this study, the micro-nano bubble technology (MBT) was used to mitigate the water pollution rapidly and continuously by increasing the concentration of dissolved oxygen (DO) in water. During treatment, the concentration of DO increased from 0.60 mg/L to over 5.00 mg/L, and the oxidation reduction potential (ORP) also changed from a negative value to over 100.00 mV after only five days aeration. High throughput pyrosequencing technology was employed to identify the microbial community structure. At genus level, the dominant bacteria were anaerobic and nutrient-loving microbes (e.g., Arcobacter sp., Azonexus sp., and Citrobacter sp.) before, and the relative abundances of aerobic and functional microbes (e.g., Perlucidibaca sp., Pseudarcicella sp., Rhodoluna sp., and Sediminibacterium sp.) were increased after treatment. Meanwhile, the water quality was significantly improved with about 50% removal ratios of chemical oxygen demand (CODCr) and ammonia nitrogen (NH4+-N). Canonical correspondence analysis (CCA) results showed that microbial community structure shaped by COD, DO, NH4+-N, and TP, CCA1 and CCA2 explained 41.94% and 24.56% of total variances, respectively. Overall, the MBT could improve the water quality of urban black-odor river by raising the DO and activate the aerobic microbes

Vertically Aligned Nickel 2‑Methylimidazole Metal–Organic Framework Fabricated from Graphene Oxides for Enhancing Fire Safety of Polystyrene

In this work, flowerlike nickel 2-methylimidazole metal–organic framework (Ni-MOF) was prepared by a solvothermal method. Vertically aligned Ni-MOF was fabricated from graphene oxide (GO) solution in the same way. The combination of GO and Ni-MOF (GOF) obviously suppressed the agglomeration of Ni-MOF sheets. As-synthesized, GOF has bigger pore volume and specific surface area, which are beneficial for volatile degradation products adsorption. It is noteworthy that the addition of GOF obviously reduced the fire hazard of polystyrene (PS). More than 33% decrease in the peak heat release rate for the PS/GOF composite was obtained when the content of the additives is only 1.0 wt %. Meanwhile, the reductions of total smoke and CO production were also prominent during the combustion of PS/GOF, respectively 21% and 52.3% decreases compared with that of pure PS. The synergism effects between layered GO and porous Ni-MOF realized the improved performances of PS. Thus, this work paves a feasible pathway to design efficient flame retardants for enhancing fire safety of polymers