Functional binders for reversible lithium intercalation into graphite in propylene carbonate and ionic liquid media

Poly(acrylic acid) (PAA), poly(methacrylic acid) (PMA), and poly(vinyl alcohol) (PVA), which have oxygen species as functional groups, were utilized as a binder for graphite electrodes, and the electrochemical reversibility of lithium intercalation was examined in PC medium and ionic liquid electrolyte, lithium bis(trifluoromethanesulfonyl)amide dissolved in 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)amide (BMP-TFSA). Columbic efficiency of 75–80% with more than 300 mAh g^?1 was achieved upon first reduction/oxidation cycle in both electrolytes using these binding polymers, which were significantly improved in comparison to a conventional PVdF binder (less than 45% of columbic efficiency for the first cycle). For the graphite-PVdF electrode, co-intercalation and/or decomposition of PC molecules solvating to Li ions were observed by the electrochemical reduction, resulting in the cracking of graphite particles. In contrast, the co-intercalation and decomposition of PC molecules and BMP cations for the first reduction process were completely suppressed for the graphite electrodes prepared with the polymers containing oxygen atoms. It was proposed that the selective permeability of lithium ions was attained by the uniform coating of the graphite particles with PAA, PMA, and PVA polymers, because the electrostatic interaction between the positively charged lithium ions and negatively charged oxygen atom in the polymer should modulate the desolvation process of lithium ions during the lithium intercalation into graphite, showing the similar functions like artificial solid-electrolyte interphase.     

A LRT Control Method Using Sensor Information in Distribution Systems with a Large Amount of PVs and EVs

It is of prime importance to maintain voltage profile within the proper range in distribution systems with a large amount of photovoltaics and electric vehicles (EVs). In particular, there is a possibility that line drop compensation (LDC) logic, which is utilized for the control of load ratio tap transformer (LRT) does not work properly when reverse power flow is included partially. Hence, in this paper, we have developed a new LRT control method based on the sensor information supposing that some section switchgears with sensors are introduced in the future distribution systems. Specifically, the extreme value of voltage profile is estimated by convergence calculation in the section between the section switchgear with sensor and LRT. Moreover, the voltage at the end node can be estimated by LDC method using sensor information of section switchgear. The proposed method was tested using a distribution system model and its effectiveness was shown.     

Novel polyion complex with interpenetrating polymer network of poly(acrylic acid) and partially protected poly(vinylamine) using N-vinylacetamide and N-vinylformamide

Poly(vinylamine), the simplest polycation with primary amines, was applied to interpenetrating polymer networks (IPN) with poly(acrylic acid). N-Vinylformamide (NVF) was employed for amino-protected monomers to control electrostatic balance. pH-responsivities of IPNs varied, depending on the hydrolysis conditions and acrylic acid (AAc) concentration of the second network. Poly(N-vinylacetamide)-co-poly(N-vinylformamide) (4/6, mol/mol) was employed for the first network, subsequently hydrolyzed with 50% amide groups, and the second network was polymerized with 0.25 mol L⁻¹ AAc, extremely shrunken hydrogels with polyion complex were formed at pH 7, showing that the controlled amount of highly active primary amines are available in IPN.     

Investigation of ring-opening polymerization of 5-[2-{2-(2-methoxyethoxy)ethoxy}-ethoxymethyl]-5-methyl-1,3-dioxa-2-one by organometallic catalysts

To develop new polymer-based materials, the design of aliphatic carbonate has received attention and become a well-known cyclic monomer. In view of carbonate ring polymer scope, poly(trimethylene carbonate) (PTMC) has been continuously developed for further applications due to its unique degradability. PTMC bearing oligo ethylene glycol units, PTMCM-MOE3OM, were typically prepared via ring-opening polymerization (ROP) using amidine-based catalysts such as 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) and benzyl alcohol (BnOH) as an initiator. To improve the polymer molecular weight or other properties, several know-how synthetic catalysts based on organometallic complexes are under consideration as potential catalysts. With the existence of diverse classes of metallic complexes, the inorganic complexes were investigated for their catalytic activity based on tris(dimethylsilyl)amido chelating, bis(phenolate) chelating, and macrocyclic tetradentate (NNNN)-type cyclen chelating with a metal-core of tin (II), scandium (III), lutetium (III), and zinc (II). In this study, we found that involving a Zn(II) dimethylcyclen/alkoxide ligand and Mg complexes could accelerate the reaction and finish the polymerization under ambient conditions within 2 hr. Molecular weight reached 11,000 g/mol (40%) and 8,100 g/mol (> 96%). Subsequently, we concluded that Zn and Mg complexes were high reactivity for initiating the ROP of TMCM-MOE3OM upon steadily degree of polymerization.     

Colour and Constitution of 1,4-Naphthoquinonoid Dyes - Modified PPP MO Calculations and Substituent Effects

Calculation of the n-electron excitation energies of naphthoquinonoid dyes has been carried out by means of the Pariser—Parr—Pople (PPP) method using the variable, β,γ-approximation. A good linear correlation between the observed and calculated values for the first π-π* excitation was found for a new series of naphthoquinonoid dyes. The effect of substituents on the colour of different dyes was studied on the basis of these calculated results, i.e. HOMO—LUMO energy levels and π-electron-density changes accompanying the excitation. The intramolecular charge-transfer character of the π-π* transition was shown to be the same as occurs in some anthraquinonoid dyes.     

Star‐shaped polycaprolactone/chitosan composite hydrogels: fabrication and characterization

Star‐shaped polycaprolactone (stPCL)/chitosan composite hydrogel was fabricated by simply melt/solution blending between chitosan/dicarboxylic acid solution and melted stPCL, using 1‐(3‐dimethylaminopropyl)‐3‐ethylcarbodiimide hydrochloride and N‐hydroxysuccinimide as conjugating agents to obtain a composite hydrogel. Here, stPCL and modified stPCL were investigated. The stPCL was modified to have a carboxyl‐terminated chain (stPCL‐COOH). The composite hydrogels were transparent. The network structure of the composite hydrogels was investigated. stPCL‐OH had no chemical bond to the chitosan network but stPCL‐COOH could co‐crosslink with the chitosan network. The porous structure and porosity of the composite hydrogels were similar to those of chitosan hydrogel. However, the hydrophobicity of stPCL resulted in a lower swelling ratio compared to chitosan hydrogel. The rheological analysis of the composite hydrogel exhibited a stable crosslinked network. Compression testing of the composite hydrogel obtained from stPCL‐COOH at a mole ratio of stPCL‐COOH and chitosan of 1:1 had optimum compressive mechanical properties comparable to chitosan hydrogel due to a synergistic effect of the flexibility in stPCL and the co‐crosslinking of stPCL‐COOH with the chitosan network. © 2020 Society of Chemical Industry     

Releasing property from surface polyion complex gel

Surface polyion complex (sPIC) gels were prepared with a nonionic hydrogel interior core, composed of poly(N‐vinylformamide and poly(N‐vinylacetamide), and a chemically bounded polyion complex layer on the outer surface, composed of poly(vinylamine) and poly(acrylic acid). The gels were investigated as controlled drug release models based on electrostatic interactions depending on pH. Methylene blue and allura red were employed as cationic and anionic drug models, respectively, and resulted in the selective adsorption depending on pH conditions. Monovalent and multivalent anionic drug models, allura red and 1,3,6‐naphthalenetrisulfonate were observed for their releasing behavior from the sPIC gel. The results indicated that the multivalent anionic drug effectively controlled release depending on pH conditions. We further investigated sPIC gels regarding their ability to control the release of ionic molecules as a function of pH‐driven changes in electrostatic interactions. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42081.     

Alignment of glycolipid nanotubes on a planar glass substrate using a two-step microextrusion technique

We have developed a two-step microextrusion technique to align lipid nanotubes of 200 nm in diameter in parallel on planar glass substrates. This technique is useful to align self-assembled molecular nanofibers or nanotubes with diameters ranging from 100 to 300 nm. In the first step, we applied relatively large air pressure (approximately 40 hPa) onto a microcapillary filled with aqueous dispersion of lipid nanotubes to push them out. An aqueous droplet with 60 microm diameter was then extruded from the tip of the microcapillary. After one end of the lipid nanotube moved out, we changed the air pressure to be smaller, approximately 20 hPa to reduce the flow rate of the dispersion. The decrease in size of the droplet allowed us to fix the exposed end of the lipid nanotube onto the planar substrate. By dragging the microcapillary along the planar surface, we were able to align the whole nanotube onto the substrate. Using this technique, we have achieved the parallel alignment of the lipid nanotubes on the glass substrate.     

A new resin system for super high solids coating

This paper concerns a super high solids coating composed of two polymers; a silicone polymer containing SiH groups, and an acrylic or polyether polymer containing C=C groups. The silicone polymer was prepared by the equilibrium reaction of SiH containing polysiloxane and other organosiloxanes in the presence of sulfuric acid. Acrylic polymers were obtained by free radical polymerization of a monomer having an alkenyl group and other vinyl monomers. Homogeneous clear paints were available by adjusting compatibility of polymers, and VOCs of the paints were very low due to the low viscosity of a silicone polymer and the absence of polar functional groups in the coating system. The crosslinking reaction of this coating occurred through the hydrosilylation reaction between SiH and C=C groups. The performances of cured films, such as etch resistance and durability, were excellent.