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

In this study, a magnesium phosphate whisker (DPM-H) was synthesized by the acid–base neutralization reaction between magnesium hydroxide and 10-hydroxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-OH) at 120°C. A new synergistic intumescent flame retardant (IFR) for epoxy resin (EP), which was composed of DPM-H and ammonium polyphosphate (APP) was thoroughly studied. When the IFR loading was 8%, with the DPM-H to APP weight ratio at 1:7, the prepared flame-retardant EP (EPDA-2) passed the vertical burning tests (UL-94) V-0 rating and obtained the limiting oxygen index (LOI) value of 29.3%. Microscale combustion calorimetry (MCC) results showed that the total heat release (THR) of EPDA-2 reduced by 32.1% compared with pure EP. Meanwhile, the addition of DPM-H can partially solve the problem of the decrease of the EP mechanical property caused by the addition of APP. Compared with the flame-retardant EP with the 8% loading of APP, the impact strength of EPDA-2 increased 152.3%.     

Metallurgical solid waste modified thermoplastic polyurethane composites: The thermal stability and combustion properties

As a kind of bulk industrial solid waste, the massive accumulation of iron tailings has caused serious waste of resources and environmental pollution. In this study, a silane coupling agent (KH550) was used to modify the surface of iron tailings to produce MIT, and it was compounded with ammonium polyphosphate (APP) on thermoplastic polyurethane (TPU) to prepare a series of TPU/APP/MIT composites. Thermogravimetric (TG), cone calorimetric (CCT), thermogravimetric infrared, scanning electron microscopy, and Raman techniques were also used to analyze the combustion performance, smoke toxicity, and microscopic morphology. The TG test results showed that the compounding of APP and MIT significantly improved the residual carbon value of TPU composites at 700°C. CCT test results showed that the TPU/APP/MIT composites exhibited excellent flame retardancy and smoke suppression. Compared with pure TPU, PHRR, THR, and TSR of TPU/APP15/MIT10 composite decreased by 85.56%, 87.83%, and 86.17%, respectively, the peak release rates of CO and CO₂ decreased by 69.26% and 90.34%, respectively. The above studies showed that APP and MIT have excellent flame retardant and smoke suppression effect on TPU materials, providing more opportunities for the study of TPU composites and metallurgical solid waste utilization.     

Enhanced sensing performance of flexible strain sensors prepared from biaxially stretched carbon nanotubes/polydimethylsiloxane nanocomposites

Flexible strain sensors from biaxially stretched carbon nanotubes (CNTs)/polydimethylsiloxane (PDMS) nanocomposites are fabricated in this study. It is shown that biaxial stretching promotes the homogeneous distribution and alignment of CNTs in the stretching plane, improving the sensing performance of the strain sensors. The optimized stretching ratios (SRs) of CNT/PDMS nanocomposites are determined. Compared to an unstretched CNT/PDMS-1.0 sensor (gauge factor [GF] value = 0.73, detectable range from 0 to 60%), the 1.5 wt% CNT/PDMS-1.5 sensor (SR = 1.5) exhibits enhanced strain sensitivity (GF = 2.8), a wider detectable range (0–370%) and better performance stability. The GF values of CNT/PDMS-2.0 and CNT/PDMS-2.5 sensors with SRs of 2.0 and 2.5, respectively, were 1.18 and 1.06, respectively, due to more significant conductive network reconstruction in the process of applying strain, leading to a decreasing GF. The possibility of sensors in the application of wearable electronic components is also demonstrated. The sensor shows a clear and stable signal output when different strain modes are applied, such as tensile, compressive, bending, and twisting.     

Synergistic flame retardancy of ZnO and piperazine pyrophosphate/melamine cyanurate in polypropylene

In order to improve the flame retardant efficiency and smoke-suppression of piperazine pyrophosphate/melamine cyanurate (PPAP/MCA) in PP, the synergism of ZnO and PPAP/MCA was investigated by limiting oxygen index (LOI) determination, UL-94 test, and cone calorimetry test (CCT). It is found that ZnO performs an exceptional synergism in flame retardant effect and inhibition on the flame propagation. Besides, ZnO can significantly inhibit the production of the smoke and CO. The TGA of the PP composites, the component and structure analysis of the heated composites and CCT residues reveal that ZnO performs the synergism primarily by the following modes: ZnO promotes obviously the charring of the composite, and improves the thermal stability as well as the strength of the intumescent layer, which brings about an improved flame retardant property and inhibiting ability on the flame propagation.     

Understanding the C?H activation of methane over single-atom alloy catalysts by density functional theory calculations

As an important rate-determining step in the oxidation of methane, the catalytic behaviors of single-atom alloys (SAAs) on the C H activation reactions have not been fully understood. In this work, density functional theory calculations are performed to investigate the C H activation of methane on a series of SAAs with Cu(111/100) and Ag(111/100) as hosts. The reaction energies and the barriers for the C H dissociation reaction follow the traditional Brønsted–Evans–Polanyi (BEP) relationship, but the deviation from this linearity fitting is relatively large. To better describe the catalytic activity, a new nonlinear binary function is proposed to correlate the reaction barrier with the adsorption energies of *H and *CH₃ products, which has higher correlation than the BEP relationship, and showed more accurate predictions of the C H activation reaction for unknown SAAs catalysis. Such mode might be able to extend to other catalyst systems to achieve large-scale catalyst screening.     

High pyroelectric response in Pb0.99Nb0.02[(Zr0.57Sn0.43)1−xTix]0.98O3 ceramics

Both high pyroelectric coefficient and figure of merits of ferroelectric materials are desirable for infrared detection. In this work, we prepared Pb_0.99Nb_0.02[(Zr_0.57Sn_0.43)_1−xTi_x]_0.98O₃ (0.060 ≤ x ≤ 0.080) ceramics, and the microstructure and electric properties were studied systematically. It is observed that the composition x = 0.07 shows enhanced pyroelectric properties around ambient temperature due to the ferroelectric–antiferroelectric phase transition, with the pyroelectric coefficient p = 6.83 × 10⁻⁴ C m⁻² K⁻¹ and the figures of merit F_i = 5.04 × 10⁻¹⁰ m V⁻¹, F_v = 7.61 × 10⁻² m² C⁻¹, and F_d = 3.46 × 10⁻⁵ Pa^−1/2 at room temperature and the highest pyroelectric coefficient of 695.5 × 10⁻⁴ C m⁻² K⁻¹ and F_i = 1410.46 × 10⁻¹⁰ m V⁻¹, F_v = 1587.39 × 10⁻² m² C⁻¹, and F_d = 1182.94 × 10⁻⁵ Pa^−1/2 at 36.7°C. These values are superior to other pyroelectric materials. These results indicate that this system is a promising pyroelectric material for the applications of infrared detectors.     

Synthesis of a Green Fuel Additive Over Cation Resins

The synthesis of polyoxymethylene dimethyl ethers (PODE_n), being green diesel fuel additives, from dimethoxymethane (DMM) and paraformaldehyde over three different cation resins, namely NKC‐9, D001‐CC, and D72, in a stirred‐autoclave reactor was investigated. The pore size distribution and surface area were measured with nitrogen adsorption‐desorption. NKC‐9 had a larger exchange capacity, better developed porosity structure, and higher reaction activity than D001‐CC and D72. The effects of reaction temperature, DMM/CH₂O molar ratio, reaction time, and catalyst loading were studied with NKC‐9. A possible mechanism was explored to describe the bond reorganizations during the reactions.     

Synthesis and Biological Evaluation of N‐Substituted Sophocarpinic Acid Derivatives as Coxsackievirus B3 Inhibitors

A series of novel N‐substituted sophocarpinic acid derivatives was designed, synthesized, and evaluated for their anti‐enteroviral activities against coxsackievirus type B3 (CVB3) and coxsackievirus type B6 (CVB6) in Vero cells. Structure–activity relationship analysis revealed that the introduction of a benzenesulfonyl moiety on the 12‐nitrogen atom in (E)‐β,γ‐sophocarpinic acid might significantly enhance anti‐CVB3 activity. Among the derivatives, (E)‐12‐N‐(m‐cyanobenzenesulfonyl)‐β,γ‐sophocarpinic acid ( 11 m ), possessing a meta‐cyanobenzenesulfonyl group, exhibited potent activity against CVB3 with a selectivity index (SI) of 107. Furthermore, compound 11 m also showed a good oral pharmacokinetic profile, with an AUC value of 7.29 μM h^?1 in rats, and good safety through the oral route in mice, with an LD₅₀ value of >1000 mg kg^?1; these values suggest a druggable characteristic. Therefore, compound 11 m was selected for further investigation as a promising CVB3 inhibitor. We consider (E)‐β,γ‐N‐(benzenesulfonyl)sophocarpinic acids to be a novel class of anti‐CVB3 agents.     

A consultation and simulation system for product color planning based on interactive genetic algorithms

In the early stage of a design process, it is important to create numerous and varied possible color plans for the target consumer group. These color plans help individual designers quickly find a few good color design schemes and give the design team ideas for brainstorming. The color plan of a product consists of the color combinations of its components and decorative patterns, which strongly influence the feelings of customers and thus their desire to purchase. However, very few studies have discussed these issues. In this study, a consultation and simulation system for product color planning that helps designers obtain the optimal color planning for components and decorative patterns of a product is proposed. This system includes two parts: one uses the interactive genetic algorithm to establish a creative evolutionary system that can interact with a designer to explore novel design schemes; the other extends the boundary extract algorithm to establish a color simulation system that can apply colors to the areas of product components and decorative patterns for color simulation. Finally, a case study of color planning for a motorcycle model is used to verify the feasibility of the proposed system. © 2012 Wiley Periodicals, Inc. Col Res Appl, 38, 375–390, 2013