Preparation and thermal effects of polyarylene ether nitrile aluminium nitride composites

Particulate‐filled polyarylene ether nitrile (PEN) composites were prepared using methyltriethoxy‐silane‐treated aluminium nitride (AlN) as the filler for thermal modification. The effects of AlN fraction, particle size and surface treatment on the thermal performance of PEN were investigated. The thermal conductivities of the composites increased when the AlN filler concentration was increased, as well as with decrement of the filler size. The thermal conductivity value of the composites increased up to 0.779 W m^?1 K^?1 when the AlN weight loading was 60 wt%. The trend of the thermal conductivities of the composites can be more efficiently predicted by theoretical models than empirical models. The composites exhibited stable performances of thermal decomposition and thermal expansion when AlN filler faction in the composites increased. © 2013 Society of Chemical Industry     

Improved morphology and enhanced stability via solvent engineering for planar heterojunction perovskite solar cells

Solvent engineering technique for planar heterojunction perovskite solar cells is an efficient way to achieve uniformly controlled grain morphology for perovskite films. In this report, diethyl ether solvent engineering technique was used for Methyl ammonium lead triiodide (CH₃NH₃PbI₃) perovskite thin films for planar heterojunction solar cells which exhibited a PCE of 9.20%. Morphological improvements and enhanced grain sizes leads to enhanced absorption of CH₃NH₃PbI₃. Moreover solar cells have showed an excellent environmental stability of more than 100 days. This increase in efficiency is due to improved film morphology of perovskite layer after solvent treatment which has been revealed under UV–Vis spectroscopy, SEM images, X-ray diffraction and impedance spectroscopy.     

Exposure to organophosphate and polybrominated diphenyl ether flame retardants via indoor dust and childhood asthma

Although the ubiquitous detection of polybrominated diphenyl ether (PBDE) and organophosphate flame retardants (PFRs) in indoor dust has raised health concerns, only very few epidemiological studies have assessed their impact on human health. Inhalation of dust is one of the exposure routes of FRs, especially in children and can be hazardous for the respiratory health. Moreover, PFRs are structurally similar to organophosphate pesticides, which have been associated with allergic asthma. Thus, we investigated whether the concentrations of PFRs and PBDEs in indoor dust are associated with the development of childhood asthma. We selected 110 children who developed asthma at 4 or at 8 years old and 110 matched controls from a large prospective birth cohort (BAMSE – Barn, Allergy, Milieu Stockholm Epidemiology). We analyzed the concentrations of 7 PFRs and 21 PBDEs in dust collected around 2 months after birth from the mother's mattress. The abundance rank in dust was as follows: TBOEP?TPHP>mmp‐TMPP>EHDPHP~TDCIPP>TCEP~TCIPP~BDE‐209?BDE‐99>BDE‐47>BDE‐153>BDE‐183>BDE‐100. There was no positive association between the FRs in mattress dust and the development of childhood asthma. In contrast, dust collected from mattresses of the mothers of children who would develop asthma contained significant lower levels of TPHP and mmp‐TMPP. This study provides data on a wide range of PFRs and PBDEs in dust samples and development of asthma in children.     

NTC-affected ignition and low-temperature flames in nonpremixed DME/air counterflow

An experimental study, supported by computation, was conducted on the coupling of NTC-chemistry and transport in the low-temperature ignition and the associated steady burning in nonpremixed DME/air counterflow. In particular, the presence of low-temperature chemical reactivity was detected nonintrusively by using a photomultiplier tube combined with a filter to capture the chemiluminescence of HCHO, which is a characteristic intermediate species formed in low-temperature chemistry. Furthermore, the ignition temperature was determined through high-sensitivity infrared imaging with proper discrimination of the background signal. Experimental results show that the transport-coupled low-temperature, NTC chemical reactivity is enhanced with smaller strain rate, higher air boundary temperature, and is insensitive to the fuel concentration. These findings agree well with those obtained from computation using detailed chemistry, leading to further identification of the controlling chemistry.     

Comparative Study on Thermodynamic Analysis of CO2 Utilization Reactions

Thermodynamic analysis of dimethyl ether (DME) and methane synthesis from CO₂ hydrogenation, and dry reforming of methane was performed using Gibbs free energy minimization. The effects of temperature, pressure, and feed composition on conversion, selectivity, and yield were investigated for each process. High pressure, high H₂/CO₂ ratio, and low temperature favored DME production. The yield of methane during CO₂ methanation increased at lower temperature, higher pressure, and H₂/CO₂ ratio. The yield of synthesis gas improved at higher temperature. Comparison of the three processes demonstrated that the CO₂ conversion was highest during CO₂ methanation reaction if the fraction of CO₂ mol in the feed was less than 0.3. Above this value in the feed, dry reforming allowed the highest CO₂ conversion.     

紫外光固化引发剂JD102的合成新工艺

紫外光固化引发剂是光固化技术的核心组成,用量少,但对反应的性能起着关键作用。光固化引发剂JD102(化学名称:1-[4-(2-羟乙氧基)苯基]2-羟基-2-甲基-1-丙酮)具有低气味、耐黄变形好、透明性佳、抗氧化阻聚、可水溶、符合FDA认证的优点,广泛用于UV油墨、木器涂料、光学等高端领域。本文以乙二醇苯醚醋酸酯和异丁酰氯为原料,通过对传统合成工艺的改进,使反应简捷,同时采用相转移催化技术,使反应效率更高、环保性更好地合成出紫外光固化引发剂JD102,并成功进行了产业化。     

Synergistic flame retardant effect of poly(ether sulfones) and polysiloxane on polycarbonate

Flame retardance of bisphenol A polycarbonate (PC) was improved by the co‐addition of poly (ether sulfones) (PES) and polysiloxane/acrylate copolymer (PSiA) while retaining a high rigidity and toughness. A UL 94 V‐0 rating for 1.6‐mm thick samples of PC/PES/PSiA blend with 10.0 wt % PES and 0.5 wt % PSiA (PC/10PES/0.5PSiA) was obtained. Its average heat release rate (av‐HRR) in a cone calorimeter measurement was decreased by 19% on the basis of PC/PES blend with 10.0 wt % PES. Scanning electron microscopy (SEM) morphologies of impact‐fractured surfaces revealed that the incorporation of 0.5 wt % PSiA decreased the dimensions of PES dispersed phase and provoked the uniform distribution of PES in PC matrix. Thermogravimetric‐Fourier transform infrared spectroscopy analysis results revealed that PSiA dominantly promoted the degradation of PC and the degraded products were combined with PES to form a superior flame‐retarded carbon layer. A higher sulfur and silicon content on the residue surface after vertical burning tests detected by SEM/energy dispersive spectrometer signified their accumulation during combustion. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

毛细管气相色谱法分析液化石油气中二甲醚含量

通过恒温水浴完全气化样品,建立了用毛细管气相色谱法测定液化石油气中二甲醚含量的方法。采用PLOT/Q（30 m×0.53 mm×40μm）毛细管柱,以热导池检测器检测,氦气为载气,以面积校正归一化法计算二甲醚含量。结果表明,该方法操作简单,实用性强,重复性好,可以用于液化石油气中二甲醚含量的分析。     

Construction of ion transport channels by grafting flexible alkyl imidazolium chain into functional poly(arylene ether ketone sulfone) as anion exchange membranes

A new series of imidazolium-functionalized anion exchange membranes (AEMs), based on poly (arylene ether ketone sulfone) containing pendant amino groups (Am-PAEKS) have been prepared. The structure of the copolymers is characterized by FT-IR and ¹H NMR spectra. The properties of the imidazolium-functionalized Am-PAEKS (Im-Am-PAEKS) including ionic conductivity, dimensional stability, thermal stability, fuel cell performance and mechanical property are investigated thoroughly. The hydroxide conductivities of the prepared membranes are in the range of 1.1 × 10^?2–13.9 × 10^?2 S cm^?1 (20–80 °C). The membranes exhibit excellent alkaline stability including high thermal stability and mechanical property after soaking in 2 M NaOH aqueous solution for 300 h. This study indicates that the imidazolium-functionalized membranes containing pedant amino groups have the potential to be applied in alkaline fuel cells.     

Influence of alkaline 2D carbon nitride nanosheets as fillers for anchoring HPW and improving conductivity of SPEEK nanocomposite membranes

In the present study, novel composite membranes were prepared based on sulfonated poly (ether ether ketone)/phosphotungstic acid/carbon nitride nanosheets (SPEEK/HPW/g-C₃N₄). The alkaline ultrathin g-C₃N₄ nanosheets in the membranes behaved like “double-sided adhesive”, forming hydrogen bonds with the HPW molecules to anchor hydrophilic HPW without leaking. Moreover, the amine groups of nanosheets formed acid–base pairs with –SO₃H of the SPEEK polymer matrix, facilitating the Grotthuss-type transport of proton to improve conductivity. The g-C₃N₄ inorganic particles provided tortuous pathways for methanol transport to suppress the methanol permeability coefficient. The selectivity of the SPEEK/HPW/g-C₃N₄-1.0 was 2.3 times higher than that of SPEEK/HPW and 1.5 times higher than that of pristine SPEEK. SPEEK/HPW/g-C₃N₄ hybrid membranes exhibited stable and durable operation for 240 h under 100% RH at 60 °C. Moreover, membranes exhibited superior mechanical property, with maximum elongation at break of 223.3%.