New liquid polysulfide polymer terminated with silyl group

The terminal SH of liquid polysulfide polymer was capped with a silyl group. This polymer was hydrolyzed immediately by moisture at ambient temperature and returned to the original polymer. The compounds of this new polymer and the various curing agents of the conventional polysulfide polymer became moisture curable and of use as one‐component sealants and adhesives. The curing speed of these compounds is very fast compared with that of not only conventional one‐component polysulfide sealants, by more than three times, but also of other one‐component sealants at 20°C under 30% humidity. Their storage stability is good. Their cured products showed physical properties comparable to those of the two‐component polysulfide compounds. In particular, the compound of this polymer and isocyanate prepolymer showed good elasticity and good weatherability. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2642–2649, 2004     

Preparation and evaluation of some novel organo‐phosphorus compounds as antioxidants and antifatigue agents in rubber

Six organo‐phosphorus compounds were synthesized and incorporated in NR and SBR mixes. The rheometric characteristics of the green rubber mixes were determined using the oscillating disc rheometer. The prepared compounds were evaluated as antioxidants and antifatigue agents in NR and SBR vulcanizates. It was found that the prepared compounds are good antioxidant and antifatigue agents and their efficiency was better than that obtained by 4‐methyl‐2,6‐di‐tert‐butyl phenol, which is used in the rubber industry. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2984–2992, 2002; DOI 10.1002/app.2327     

Novel phosphorus‐containing hardeners with tailored chemical structures for epoxy resins: Synthesis and cured resin properties

A comparative evaluation of systematically tailored chemical structures of various phosphorus‐containing aminic hardeners for epoxy resins was carried out. In particular, the effect of the oxidation state of the phosphorus in the hardener molecule on the curing behavior, the mechanical, thermomechanical, and hot‐wet properties of a cured bifunctional bisphenol‐A based thermoset is discussed. Particular attention is paid to the comparative pyrolysis of neat cured epoxy resins containing phosphine oxide, phosphinate, phosphonate, and phosphate (with a phosphorus content of about 2.6 wt %) and of the fire behavior of their corresponding carbon fiber‐reinforced composites. Comparatively faster curing thermosetting system with an enhanced flame retardancy and adequate processing behavior can be formulated by taking advantage of the higher reactivity of the phosphorus‐modified hardeners. For example, a combination of the high reactivity and of induced secondary crosslinking reactions leads to a comparatively high T_g when curing the epoxy using a substoichiometric amount of the phosphinate‐based hardener. The overall mechanical performance of the materials cured with the phosphorus‐containing hardeners is comparable to that of a 4,4′‐DDS‐cured reference system. While the various phosphorus‐containing hardeners in general provide the epoxy‐based matrix with enhanced flame retardancy properties, it is the flame inhibition in the gas phase especially that determines the improvement in fire retardancy of carbon fiber‐reinforced composites. In summary, the present study provides an important contribution towards developing a better understanding of the potential use of such phosphorus‐containing compounds to provide the composite matrix with sufficient flame retardancy while simultaneously maintaining its overall mechanical performance on a suitable level. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

有机膨润土的合成及应用

介绍了有机膨润土的合成原理和方法以及一些常见的有机化试剂，并详细地介绍了它在纺织工业、深井钻井泥浆、耐高温润滑脂、乳液方面、油漆油墨等方面的应用。     

The investigation on the curing process of polysulfide sealant by in situ dielectric analysis

In this work, in situ dielectric analysis (DEA) was employed for the first time to the best of our knowledge, to monitor the curing process of polysulfide (PSF) sealant using manganese dioxide (MnO₂) as the curing agent, where the gel point and ending point were determined. The obtained results were verified by rheological tests of dynamic mechanical analysis and tensile strength tests. It showed a significant difference between this curing process and those of usual thermosetting materials. The influences of the pH value of the samples and curing temperature were investigated and discussed in detail. Also, activation energies of the curing reaction of the samples with different pH values were calculated. The results proved DEA as a reliable and useful method for in situ monitoring PSF–MnO₂ curing process. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Recent advances of small-molecule fluorescent probes for detecting biological hydrogen sulfide

H₂S is well-known as a colorless,acidic gas,with a notoriously rotten-egg smell.It was recently revealed that H₂S is also an endogenous signaling molecule that has important biological functions,however,most of its physiology and pathology remains elusive.Therefore,the enthusiasm for H₂S research remains.Fluorescence imaging technology is an important tool for H₂S biology research.The development of fluorescence imaging technology has realized the study of H₂S in subcellular organelles,facilitated by the development of fluorescent probes.The probes reviewed in this paper were categorized according to their chemical mechanism of sensing and were divided into three groups:H₂S reducibility-based probes,H₂S nucleophilicity-based probes,and metal sulfide precipitation-based probes.The structure of the probes,their sensing mechanism,and imaging results have been discussed in detail.Moreover,we also introduced some probes for hydrogen polysulfides.     

Electron-State Confinement of Polysulfides for Highly Stable Sodium–Sulfur Batteries

Confinement of polysulfides in sulfur cathodes is pivotal for eliminating the “shuttle effect” in metal–sulfur batteries, which represent promising solutions for large-scale and sustainable energy storage. However, mechanistic exploration and in-depth understanding for the confinement of polysulfides remain limited. Consequently, it is a critical challenge to achieve highly stable metal–sulfur batteries. Here, based on a 2D metal–organic framework (2D MOF), a new mechanism to realize effective confinement of polysulfides is proposed. A combination of in situ synchrotron X-ray diffraction, electrochemical measurements, and theoretical computations reveal that the dynamic electron states of the Ni centers in the 2D MOF enable the interaction between polysulfides and the MOF in the discharge/charge process to be tuned, resulting in both strong adsorption and fast conversion kinetics of polysulfides. The resultant room-temperature sodium–sulfur batteries are amongst the most stable reported so far, thus demonstrating that the new mechanism opens a promising avenue for the development of high-performance metal–sulfur batteries.     

Shielding Polysulfide Intermediates by an Organosulfur-Containing Solid Electrolyte Interphase on the Lithium Anode in Lithium–Sulfur Batteries

The lithium–sulfur (Li–S) battery is regarded as a promising high-energy-density battery system, in which the dissolution–precipitation redox reactions of the S cathode are critical. However, soluble Li polysulfides (LiPSs), as the indispensable intermediates, easily diffuse to the Li anode and react with the Li metal severely, thus depleting the active materials and inducing the rapid failure of the battery, especially under practical conditions. Herein, an organosulfur-containing solid electrolyte interphase (SEI) is tailored for the stabilizaiton of the Li anode in Li–S batteries by employing 3,5-bis(trifluoromethyl)thiophenol as an electrolyte additive. The organosulfur-containing SEI protects the Li anode from the detrimental reactions with LiPSs and decreases its corrosion. Under practical conditions with a high-loading S cathode (4.5 mg_S cm⁻²), a low electrolyte/S ratio (5.0 µL mg_S⁻¹), and an ultrathin Li anode (50 µm), a Li–S battery delivers 82 cycles with an organosulfur-containing SEI in comparison to 42 cycles with a routine SEI. This work provokes the vital insights into the role of the organic components of SEI in the protection of the Li anode in practical Li–S batteries.     

Rational Integration of Polypropylene/Graphene Oxide/Nafion as Ternary‐Layered Separator to Retard the Shuttle of Polysulfides for Lithium–Sulfur Batteries

The reversible electrochemical transformation from lithium (Li) and sulfur (S) into Li₂S through multielectron reactions can be utilized in secondary Li–S batteries with very high energy density. However, both the low Coulombic efficiency and severe capacity degradation limits the full utilization of active sulfur, which hinders the practical applications of Li–S battery system. The present study reports a ternary‐layered separator with a macroporous polypropylene (PP) matrix layer, graphene oxide (GO) barrier layer, and Nafion retarding layer as the separator for Li–S batteries with high Coulombic efficiency and superior cyclic stability. In the ternary‐layered separator, ultrathin layer of GO (0.0032 mg cm^?2, estimated to be around 40 layers) blocks the macropores of PP matrix, and a dense ion selective Nafion layer with a very low loading amount of 0.05 mg cm^?2 is attached as a retarding layer to suppress the crossover of sulfur‐containing species. The ternary‐layered separators are effective in improving the initial capacity and the Coulombic efficiency of Li–S cells from 969 to 1057 mAh g^?1, and from 80% to over 95% with an LiNO₃‐free electrolyte, respectively. The capacity degradation is reduced from 0.34% to 0.18% per cycle within 200 cycles when the PP separator is replaced by the ternary‐layered separators. This work provides the rational design strategy for multifunctional separators at cell scale to effective utilizing of active sulfur and retarding of polysulfides, which offers the possibility of high energy density Li–S cells with long cycling life.