Synthesis of PMMA-co-PMAA Copolymer Brush on Multi-Wall Carbon Nanotubes

Poly(methyl methacrylate)/poly(methacrylamide) copolymer (PMMA-co-PMAA) was synthesized by a free radical copolymerization of MMA and MAA monomers in methylethyl ketone using AIBN as radical initiator. Multi-wall carbon nanotubes (MWCNT) were oxidized in KMnO4 acidic suspension. Carboxyl groups on the surface oxidized MWCNT were reacted with primary amide group of PMMA-co-PMAA copolymer in MEK solution under ultrasound to form polymer brush on the surface of MWCNT. With the help of TG analyses the amount of covalently grafted PMMA-co-PMAA copolymer onto MWCNT surface was determined as ?47 wt%. TEM analyses identified thin co-polymer layer adhered onto MWCNT surface with average thickness ?5 nm.

Effect of Glow-Discharge Air Plasma Treatment on Wettability of Synthetic Polymers

Main aim of this study was focused on characterization of the effect of microwave air plasma treatment on wettability of synthetic polymer surfaces. Wettability of solid polymer surfaces polyethylene, polypropylene, polystyrene (PE, PP, PS) was followed as a function of plasma treatment time. For evaluation the equilibrium contact angles of wetting as well as dynamic contact angles of wetting were determined by means of sessile drop and Wilhelmy plate methods. Free surface energy (SFE) of studied samples were calculated from the experimentally determined contact angles using Fowkes and van Oss, Chaudhury and Good (vOCG) approaches. It was found that with prolonged treatment time the total surface free energy of PE was two times increased from 23 mJ/m2 to 45 mJ/m2 after 360 s plasma treatment time (calculated for W and EG as wetting liquids). Similar effect was found for all studied polymers. With respect to the dispersive and polar components of the total surface free energy the vigorous effect was found for polar component, for which it was increased from 7 mJ/m2 to 20 mJ/m2.

ZnO@MOF@PANI core-shell nanoarrays on carbon cloth for high-performance supercapacitor electrodes

Hierarchical ZnO@metal-organic framework @polyaniline(ZnO@MOF@PANI) core-shell nanorod arrays on carbon cloth has been fabricated by combining electrodeposition and hydrothermal method. Well-ordered Zn O nanorods not only act as a scaffold for growth of MOF/PANI shell but also as Zn source for the formation of MOF. The morphology of ZnO@MOF@PANI composite is greatly influenced by the number of PANI electrodeposition cycles. Their structural and electrochemical properties were characterized with different techniques. The results indicate that the Zn O@MOF@PANI with 13 CV cycles of PANI deposition demonstrates the maximum specific capacitance of 340.7 F g-1 at 1.0 A g-1, good rate capability with84.3% capacitance retention from 1.0 to 10 A g-1 and excellent cycling life of 82.5% capacitance retention after 5000 cycles at high current density of 2.0 A g-1. This optimized core-shell nanoarchitecture endows the composite electrode with short ion diffusion pathway, rapid ion/electron transfer and high utilization of active materials, which thus result in excellent electrochemical performance of the ternary composite.

Nano storage-boxes constructed by the vertical growth of MoS_(2 )on graphene for high-performance Li-S batteries

In order to accelerate the reaction kinetics of lithium-sulfur batteries, the introduction of electro catalysis and proper structural control of the sulfur cathode is urgently needed. MoS_(2) nano sheets was selectively grown vertically (V-MoS_(2)) on the microwave-reduced graphene (rGO) sheets through chemical coupling to construct a self-supporting sulfur cathode with a nano storage-box structure (V-MoS_(2) as the wall and rGO as the bottom). RGO, which has a high conductivity of 37 S cm^(−1), greatly accelerates the transfer of electrons from the active sites on the edge of the layer to the solution. The introduction of carbon tubes can connect the abundant pores in the foam and act as a long-range conductive path. The 2D-orthogonal-2D structure maximally exposes the edge active sites of MoS_(2), and together with graphene form a nano reactor of sulfur, intermediate lithium polysulfides and discharge product Li_(2)S(2). The effective combination of the microstructure confinement of the nano storage-boxes and the efficient synchronous catalytic mechanism of V-MoS_(2) greatly improves the electrochemical performance of the lithium-sulfur batteries. As a result, the assembled lithium-sulfur battery displays a high initial discharge capacity of 1379 mAh g^(−1), good cycle stability (86% capacity retention after 500 cycles at 0.1C) and superior rate performance.

Confining MoS_(2) nanocrystals in MOF-derived carbon for high performance lithium and potassium storage

Developing an efficient synthesis protocol to simultaneously control 2D nanomaterials’size and dispersion is the pivot to optimize their electrochemical performance.Herein,we report the synthesis of uniform MoS_(2) nanocrystals well-anchored into the void space of porous carbon(donated as MoS_(2)3C hybrids)by a simple confined reaction in metal–organic framework(MOF)during carbonization process.The strong confinement effect refrain MoS2 growth and aggregation,generating abundant active centers and edges,which contribute fast lithium/potassium reaction kinetics.In addition to the hybridization with the derived carbon,the MoS_(2)3C hybrids exhibit rapid Liþtransfer rate(~109 cm^(2) s 1)and greatly improved electronic conductivity.Consequently,the MoS23C hybrids show ultrafast rate performances and satisfactory cycling stabilities as anode materials for both lithium and potassium ion batteries.This work demonstrates a universal tactic to achieve high dispersive 2D nanomaterials with tailorable particle size.

EPR Study of the Thermal Decomposition of Transannular Peroxide of Anthracene

Thermal decomposition of transannular peroxide of anthracene (POA) (or 9,10-epidioxido anthracene) was studied by means of electron paramagnetic resonance spectroscopy (EPR) in the solid as well as in the liquid phases. Decomposition process proceeds via cleavage of the O-O bridge of the POA molecule, generating thus an alcoxy intermediate radical. Its concentration increases to a certain equilibrium stage during the time scale of the experiment. EPR spectra in the solid state were of the singlet type at the temperatures over 350 K, a doublet like anisotropic spectra were measured at the room temperature, both having g-value 2.0033. EPR spectrum from POA decomposed in benzene indicates four protons with higher (2aH = 0.305 mT, 2aH = 0.335 mT) and four protons with a lower (2aH = 0.075 mT, 2aH = 0.105 mT) splitting constants, corresponding well the radical expected after cleavage of O-O bridge.

Removal of endocrine disrupting chemicals from water through urethane functionalization of microfiltration membranes via electron beam irradiation

Polyethersulphone(PES)membranes modified with urethane functional groups were prepared through an interfacial reaction using electron beam irradiation.The removal of eight endocrine disrupting chemicals(EDCs)was studied using both pristine and functionalized PES membranes.The prepared membranes underwent characterization using several techniques,including attenuated total reflectance-Fourier transform infrared(ATR-FTIR)spectroscopy,scanning electron microscopy,contact angle analysis,and measurements of pure water flux.Furthermore,dynamic adsorption experiments were conducted to evaluate the adsorption mechanism of the prepared membrane toward the eight EDCs.The urethane functionalized membranes were hydrophilic(52°contact angle)and maintained a high permeate flux(26000 L/h m^(2) bar)throughout the filtration process.Dynamic adsorption results demonstrated that the introduction of urethane functional groups on the membranes significantly enhanced the removal efficiency of 17β-estradiol,estriol,bisphenol A,estrone,ethinylestradiol,and equilin.The adsorption loading of 17β-estradiol on the functionalized PES membrane was 6.7±0.7 mg/m^(2),exhibiting a 5-fold increase compared to the unmodified PES membrane.The membranes were successfully regenerated and reused for three adsorption cycles without experiencing any loss of adsorption capacity.

Highly surface electron-deficient Co_(9)S_(8) nanoarrays for enhanced oxygen evolution

Tailoring valence electron delocalization of transition metal center is of importance to achieve highly-active electrocatalysts for oxygen evolution reaction(OER).Herein,we demonstrate a“poor sulfur”route to synthesize surface electron-deficient Co_(9)S_(8) nanoarrays,where the binding energy(BE)of Co metal center is considerably higher than all reported Co_(9)S_(8)-based electrocatalysts.The resulting Co_(9)S_(8) electrocatalysts only require the overpotentials(h)of 265 and 326 mV at 10 and 100 mA cm^(-2) with a low Tafel slope of 56 mV dec^-(1) and a 60 hlasting stability in alkaline media.The OER kinetics are greatly expedited with a low reaction activation energy of 27.9 kJ mol^-(1) as well as abundant OOH*key intermediates(24%),thus exhibiting excellent catalytic performances.The surface electron-deficient engineering gives an available strategy to improve the catalytic activity of other advanced non-noble electrocatalysts.

可生物降解聚乙烯-羧甲基纤维素水凝胶薄膜

0引言 近年来,随着人们生态意识的不断增强,开发环保型包装材料已成为现代包装行业的热门研究方向之一。包装可分为三大类：初级包装（接触商品并随商品一并销售的包装）、二级包装（用于携带大量的初级包装商品的较大包装,例如盒子）、三级包装（用于协助大批量货物运输的包装,例如木托盘和塑料包装）。通常,二级包装和三级包装材料容易收集和清理回收。

Effect of a Hybrid Zinc Stearate-Silver System on the Properties of Polylactide and Its Abiotic and the Biotic Degradation and Antimicrobial Activity Thereof

This work investigates the degradation and properties of a thermoplastically prepared composite comprising a polylactide/ hybrid zinc stearate-silver system. The influence of the zinc stearate-silver system on the properties of the composite is investigated by electron microscopy, differential scanning calorimetry and tensile tests. Furthermore, the antimicrobial activities of the systems are examined. The degradation behaviour of the composites is studied in both abiotic and biotic （composting） environments at an elevated temperature of 58 ℃. The results reveal good dispersion of the additive in the PLA matrix, a stabilizing effect exerted by the same on the polylactide matrix during processing, and slight reduction in glass transition temperature. The zinc stearate-silver component also reduces brittleness and extends elongation of the composite. Abiotic hydrolysis is not significantly affected, which is in contrast with pure PLA, although mineralization during the early stage of biodegradation increases noticeably. The composite exhibits antimicrobial activity, even at the lowest dosage of the zinc stearate/silver component （1 wt%）. Moreover, Ag and Zn contents were found to be present in the composite during abiotic hydrolysis, which was demonstrated by minimal diffusion of Ag ions from the matrix and very extensive washing of compounds that contained Zn.

Plasma-enabled sensing of urea and related amides on polyaniline

The atmospheric pressure plasma jet （APPJ） was used to enhance the sensitivity of industrially important polyaniline （PANI） for detection of organic vapors from amides. The gas sensing mechanism of PANI is operating on the basis of reversible protonation or deprotonation, whereas the driving force to improve the sensitivity after plasma modifications is unknown. Herein we manage to solve this problem and investigate the sensing mechanism of atmospheric plasma treated PANI for vapor detection of amides using urea as a model. The results from various analytical techniques indicate that the plausible mechanism responsible for the improved sensi- tivity after plasma treatment is operating through a cyclic transition state formed between the functional groups introduced by plasma treatment and urea. This transition state improved the sensitivity of PANI towards 15 ppm of urea by a factor of 2.4 times PANI. This plasma treated compared to the non-treated PANI is promising for the improvement of the sensitivity and selectivity towards other toxic and carcinogenic amide analytes for gas sensing applications such as improving material proces- sing and controlling food quality.

Rheology of Poly(vinyl butyral)Solution Containing Fumed Silica in Correlation with Electrospinning

The rheological properties in question are influenced by many factors, ranging from the characteristics of the given polymer or solvent to the flowing conditions. The primary focus of this study is to analyse the rheological behaviour of poly（vinyl butyral）—Mowital B 60 H—（PVB） solutions dissolved in methanol and a blend of these with fumed silica nanoparticles. The preparation of the nanofibrous web and the quality of nanofibres were correlated with the rheology of the polymer solution. It was discerned that drastically intensifying shear viscosity and the elasticity of the solution exerted a negligible effect on the formation of fibres, a finding which has rarely been discussed in the literature. The morphologies and structures of the PVB/silica nanofibrous membranes were investigated by scanning electron microscopy, thermogravimetric analysis and Fourier transform infrared spectroscopy.