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排序方式: 共有107条查询结果,搜索用时 921 毫秒
51.
Yating Li Zuhao Yu Prof. Jianhang Huang Prof. Yonggang Wang Prof. Yongyao Xia 《Angewandte Chemie (International ed. in English)》2023,62(47):e202309957
Problems of zinc anode including dendrite and hydrogen evolution seriously degrade the performance of zinc batteries. Solid electrolyte interphase (SEI), which plays a key role in achieving high reversibility of lithium anode in aprotic organic solvent, is also beneficial to performance improvement of zinc anode in aqueous electrolyte. However, various studies about interphase for zinc electrode is quite fragmented, and lack of deep understanding on root causes or general design rules for SEI construction. And water molecules with high reactivity brings serious challenge to the effective SEI construction. Here, we reviewed the brief development history of zinc batteries firstly, then summarized the approaches to construct SEI in aqueous electrolyte. Furthermore, the formation mechanisms behind approaches are systematically analyzed, together with discussion on the SEI components and evaluation on electrochemical performance of zinc anode with various types of SEI. Meanwhile, the challenge between lab and industrialization are also discussed. 相似文献
52.
The use of an epoxidized fatty acid ester (EFAE) as a natural-based plasticizer for plasticized PVC (P-PVC) has been evaluated in this work. The effect of the curing conditions has been studied by following several test techniques such as mechanical properties, thermal behavior, color changes, solvent migration and microstructure. Different curing processes at isothermal conditions (ranging from 160 °C to 220 °C) have been carried at curing times in the 6–16 min range. The optimum mechanical response (tensile strength values in the 9–10 MPa range and elongation at break close to 250%) is obtained for plastisols cured at 200 and 220 °C for 12 and 8 min curing times, respectively. These curing conditions also offer the lowest migration in n-hexane (lower than 11%) which is indicative of plasticizer total absorption. Furthermore, the use of these curing conditions does not lead to thermal degradation as confirmed by color measurements. 相似文献
53.
Long-term heat stabilisation by (natural) polyols in heavy metal- and zinc-free poly(vinyl chloride)
Johan Steenwijk Rik Langerock Jacco van Haveren Leonardus W. Jenneskens 《Polymer Degradation and Stability》2006,91(1):52-59
The long-term heat stabilisation efficiency of (natural) polyol additives in heavy metal- and zinc-free poly(vinyl chloride) (PVC) has been investigated. It is shown that polyols, such as sorbitol and xylitol, markedly reduce the dehydrochlorination rate and improve Congo Red values. Extraction experiments on unprocessed and ground-processed PVC-sorbitol (1.0 phr) mixtures after thermal degradation at 200 °C revealed that especially in the ground-processed PVC-sorbitol system, sorbitol is partly converted into its mono- and dianhydro-derivatives 1,4-sorbitan and isosorbide, respectively. Apparently, the HCl released during thermal degradation acts as the catalyst. Similar intramolecular cyclodehydration reactions also occur with the natural polyols, erythritol and xylitol, under these conditions. Scrutiny of the measured dehydrochlorination rates and the Congo Red values for ground-processed heavy metal- and zinc-free PVC-polyol mixtures show that in particular polyols containing primary hydroxyl groups exert long-term heat stabilisation and that they act as efficient HCl scavengers. 相似文献
54.
The development of novel PP textiles requires materials of which the surface has well defined hydrophilic properties, for instance, by the use of additives before extrusion and drawing. The feasibility of static secondary ion mass spectrometry (S-SIMS) to provide detailed information on the molecular surface composition of materials in the form of 30 μm thick films has been explored. Extensive charge build-up during S-SIMS analysis prevents direct characterisation of such materials. Several methods have been used to circumvent the problem. Specifically, deposition of gold over the entire surface and pressing a slot grid into the material allow the commercial hydrophilic additive in PP to be detected. While the slot grid preserves the pristine surface composition, mass spectra from gold-coated samples reflect the occurrence of redistribution artefacts. 相似文献
55.
Cristiana A. Ittner Mazali 《European Polymer Journal》2009,45(8):2222-2233
Silicone-based additives have been used as fire retardants for thermoplastics with the advantageous of improving the processing and the impact resistance of the polymers. In this work the influence of these additives on the curing kinetics of a vinyl ester resin was studied. Three silicone-based additives were used to modify the properties of the vinyl ester resin. The principal differences between them are the functional groups inserted in the polydimethylsiloxane chains. The additives were dispersed in the resin containing a commonly used mixture of initiator and catalyst methylethylKetone peroxide and cobalt-II octanoate, respectively. For some reactional mixtures N,N-dimethylaniline (DMA) was used as promoter. Differential scanning calorimetry (DSC) was used to perform the non-isothermal cure of the non-modified resin and of the resins modified with the additives. Ozawa´s, Kissinger´s and Ozawa´s isoconversional methods were used to determine the kinetic parameters. For resin cured in absence of DMA the silicone-based additives act as retardants for the curing reaction, a typical diluent effect, while in presence of this promoter the reaction enthalpy as well as the reaction rate were improved. This effect was attributed to specific interactions and reactions between DMA and the silicone-based additives that changed the curing mechanism as well as controlled the phase segregation. 相似文献
56.
Pesticides have been the major contributors to the growth of agricultural productivity, but the wide spread use in the fields and discharge from the manufacturing industries have also contributed to environmental concerns. In the present work, degradation of triazophos (O,O-diethyl-O-(1-phenyl-1H-1,2,4-triazol-3-yl) phosphorothioate) as a model pollutant has been investigated using high volume continuous ultrasonic flow cell for the first time. Effect of power dissipation and initial pH on the extent of triazophos degradation using acoustic cavitation has been investigated initially. Under the optimized set of operating power dissipation and pH, effect of addition of hydrogen peroxide (ratio of C12H16N3O3PS (Triazophos):H2O2 over the range of 1:1–1:5), ozone (over the flow rate of 100–400 mg/h) and Fenton’s reagent (C12H16N3O3PS:FeSO4:H2O2 ratio over the range of 1:1:1–1:4:4) has been investigated as possible process intensification strategy. Combined operation of US with H2O2 and Ozone resulted in 48.6% and 54.6% triazophos degradation respectively whereas combination of US and Fenton’s reagent resulted in maximum degradation as 92.2% and also resulted in maximum COD removal as 88.5%. The study also focused on identification of intermediate products formed during the degradation as well as establishing the kinetic rate constants and the synergistic index for different approaches. The study has established that cavitation can be effectively used for triazophos degradation with significant intensification benefits based on the use of combination approach. 相似文献
57.
Adrian Boborodea Stephen O’Donohue 《International Journal of Polymer Analysis and Characterization》2017,22(4):305-309
The study presents the possibility of performing the analysis of oligomeric structures and polymer additives by gel permeation chromatography (GPC) with atmospheric pressure chemical ionization (APCI) mass spectrometry (MS) in dibuthoxymethane (DBM, butylal), a halogen-free and less hazardous solvent than typically used chloroform and tetrahydrofuran. Polystyrene oligomers and Irganox® additives were analyzed in DBM using 2.1?mm internal diameter GPC columns, allowing to decrease the flow rate down to 50?µL/min, compatible with APCI–MS interface. The ionization was controlled by adding 1% chloroform in DBM to obtain (M+Cl)? adducts, allowing a fast optimization of method parameters. 相似文献
58.
59.
胶束电动毛细管电泳同时测定饮料中的多种添加剂 总被引:4,自引:0,他引:4
建立了分析饮料中山梨酸,苯甲酸,10-羟基基癸烯酸,咖啡因和糖精钠五种添加剂的胶束电动细管电泳法。讨论了电压,缓冲溶液浓度和PH值,胶束浓度对分析结果的影响。5种添加剂的迁移时间和测定回收率的变异系数分别小于1.5%和5%,检测限分别为10,10,5,10,20μg/kg。 相似文献
60.
Jingzhi Han Shunquan Liu Changsheng Wang Haiying Chen Honglin Du Yingchang Yang 《Journal of magnetism and magnetic materials》2009,321(9):1331-1334
Effects of the conventional hydrogenation disproportionation desorption recombination (HDDR) process and the additions of Co and Zr on anisotropy of HDDR PrFeB-type magnetic materials are investigated. The results show that the degree of anisotropy in conventional HDDR Pr13Fe80B7 materials decreases monotonically with the prolonged disproportionation time, and short disproportionation time is helpful for preparing highly anisotropic Pr13Fe80B7 material. However, it is notable that the degree of anisotropy in conventional HDDR Pr13Fe80B7 materials is significantly smaller than that in solid-HDDR Pr13Fe80B7 materials with the same disproportionation time. At the same time, it is found that the addition of Co and Zr may make HDDR Pr-Fe-B materials that have higher anisotropy compared with HDDR pure ternary Pr13Fe80B7 materials under the same HDDR process, but their degree of anisotropy will also decrease monotonically with the prolonged disproportionation time, and will be close to zero when the disproportionation time is greater than 20 h. Based on this, the origin of anisotropy is discussed by X-ray diffraction (XRD) investigations for the disproportionated products of the above alloys. The results show that the origin of anisotropy in HDDR Pr-Fe-B materials with the addition of Co or Zr may differ from that in HDDR pure Pr13Fe80B7 materials, and the former maybe from the residual “Pr2(Fe,Co,Zr)14B” nucleus while the latter is not. Finally, it is also found that HDDR Pr-Fe-B materials with Co or Zr can obtain high-magnetic properties even if the high-desorption temperature is used, and this shows the addition of Co and Zr may make HDDR Pr-Fe-B materials that have a larger process temperature range. 相似文献