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We synthesized a novel bivalent monomer 1 bearing 4-vinylbenzyl group and five-membered cyclic dithiocarbonate. This monomer 1 was polymerized orthogonally by free radical polymerization to afford polystyrene 1a bearing a five-membered cyclic dithiocarbonate moiety in the side chain. On the other hand, cationic ring-opening polymerization of five-membered cyclic dithiocarbonate in the monomer 1 successfully proceeded, resulting in a narrow molecular weight distribution of polydithiocarbonate 1b bearing a 4-vinylbenzyl group in the side chain. Furthermore, post-polymerizations of 1a and 1b maintaining the polymerizable functionality were carried out respectively by suitable polymerization methods. The five-membered cyclic dithiocarbonate of 1a underwent cationic ring-opening polymerization with a high molar ratio of methyl trifluoromethanesulfonate at a high temperature compared to the case of monomer 1, whereas radical polymerization of the 4-vinylbenzyl group of 1b successfully proceeded under the almost same conditions as the case of monomer 1. These post-polymerizations achieved the synthesis of corresponding networked polymers 2a and 2b.

A dibenzylamine derived cyclic dithiocarbonate (1) undergoes ring-opening polymerization due to the greater reactivity of exocyclic sulfur compared to the tertiary amine with methyl triflate.

Close contact is unavoidable in the care of patients with neuromuscular diseases (NMD). In addition, respiratory physiotherapy and noninvasive ventilation generate massive amounts of aerosols. Caring for a patient suffering from coronavirus disease‐19 raises concerns about the risk of infection not only to the caregiver and/or medical staff but also to other individuals in contact with these personnel. We reviewed the points to be noted in infection control when a patient with neuromuscular diseases receiving respiratory care is infected with COVID‐19 and summarizes the recommendation. Infected patients must be isolated in a negative‐pressure or actively ventilated room. Clear zoning separating clean and infected areas should be performed for pathogen containment. Caregivers should wear appropriate personal protective equipment and thoroughly clean their hands. Leak‐prevention measures and the use of proper respiratory circuits and filters with virus‐removal performance are crucial to reducing aerosols in noninvasive ventilation. Although respiratory physiotherapy is essential, treatment should be minimized in consideration of the infection state and sputum status, and alternative therapies such as postural drainage should be carefully considered. Infection control is distinctly obligate; however, it impairs the quality of life and activity of daily living significantly. We should implement it with enough ethical consideration, adequate explanation, and patient consent. We hope that this paper will contribute to appropriate COVID‐19 infection control in patients with neuromuscular diseases requiring respiratory care.

Nα,Ne-(Phenoxycarbonyl)-l-lysine methyl ester 1a can be expected to behave as a difunctional blocked diisocyanate monomer derived from l-lysine with diphenyl carbonate. In this report, we examined ...

We have already found that the polymers, which are obtained by the polymerization of 4‐vinylphenyl isothoiocyanate after the zwitterion formation with cyclic amidines, are networked through the ionic interaction among the zwitterions becoming insoluble to various solvents. We report here on the results of the reaction of nucleophilic reagents such as amines and alcohols with the zwitterionic adduct to investigate about the decrosslinking through the resolution of ionic interactions. In the model reactions of amines and alcohols with the zwitterion compounds, which were consisted of the phenyl isothiocyanate and cyclic amidines, the reaction of nucleophilic reagents and zwitterionic adducts having methyl group at the 2‐position of the amidine proceed quantitatively. Based on the model reaction, such nucleophilic addition was applicable to decrosslinking reaction of the networked polymers containing the zwitterion structure in the side‐chain. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2131–2137

Aliphatic polydithiourethanes (PDTUs) were successfully synthesized from diisothiocyanates and dithiols having different values of the carbon atom number. The thermal properties and hydrogen-bonding behavior of PDTUs were studied in detail by using differential scanning calorimetry, thermal gravimetric analysis, temperature dependence nuclear magnetic resonance, Fourier transform infrared-attenuated total reflection, and density functional theory and semiempirical molecular orbital methods. In this work, we demonstrated that the thermal decomposition of PDTUs happened from the cleavage of the C–S bond of the dithiocarbamate moiety in the main chain and also that the active isothiocyanate and thiol groups were reprepared in the terminal of the decomposed polymer (i.e., oligomer). Furthermore, we found that the thermal depolymerization of PDTUs and the repolymerization of dithiourethane oligomers at room temperature proceeded repeatedly a few times.

Diamond-like carbon (DLC) coatings are typically used to reduce the friction of sliding parts in automobiles. However, the utilization of DLC coatings in oils containing molybdenum dithiocarbamate (MoDTC) additive causes severe wear of these parts. In this work, we modified the compositions of DLC coatings by varying the cathodic arc deposition process conditions and investigated the effects of the modified compositions on the coating wear properties. The results showed that the wear loss of the DLC coatings increased with the increasing hydrogen concentration or ratio between the sp2- and sp3-hybridized carbon atoms. In addition, the molybdenum oxide species produced during the MoDTC decomposition interacted with the double bonds of the DLC coatings, leading to their cleavage.

The efficient CO2 fixation by N-benzyl cyclic guanidine 1 was achieved by bubbling dry CO2 through CH3CN at 25 °C for 2 h. In addition, the zwitterion adduct 2 and bicarbonate salt 3 were selectively prepared from 1 under dry (in anhydrous CH3CN) and wet (in CH3CN containing an equimolar amount of water for 1) conditions, respectively. Both compounds 2 and 3 were isolated as white solids and their structures were characterized in detail by elemental analysis, FTIR-ATR, solid-state NMR, TGA, and DFT calculation. These analytical results obviously revealed the formation of a zwitterion adduct and bicarbonate salt from N-benzyl cyclic guanidine and CO2. Especially, the zwitterion adduct of the monocyclic guanidine derivative and CO2 was isolated and characterized for the first time.

4-Hydroxymethyl 2-oxazolidinones have been successfully synthesized under mild conditions by the intramolecular cyclization of glycidyl carbamate derivatives with a bicyclic guanidine as the efficient catalyst. This reaction system, which is also applicable to the multifunctional compounds, can provide bi- and tri-functional alcohols having oxazolidinone moieties.

A racemic mixture and two chiral monomers of 2-methyl-1-butyl propiolate, i.e., rac1, R1, and S1, were stereoregularly polymerized with a catalyst, [Rh(norbornadiene)Cl]2, in methanol at 40 °C to obtain the corresponding helical racemic and two chiral polymers, Prac1, PR1, and PS1, and a copolymer, Pco. The 1H and 13C NMR spectra of the racemic and chiral polymers differed, although the NMR spectra of their monomers were the same. The structures of the Pco copolymers with different chiral monomer ratios were analyzed using 1D and 2D NMR, optical rotation, circular dichroism (CD), UV–vis, and computational methods to elucidate the stereochemical effect of the chiral monomers together with the polymerization mechanism. The temperature dependence of 1H and 13C NMR spectra in line shape and intensity indicated that the helical main chain undergoes restricted rotation around the ester methylene bonds −O–CH2– through a three-site jump exchange called an accordion-like helix oscillation (HELIOS). The energetical...

Radical copolymerization, with various monomer feeds of phenyl vinylethylene carbonate (PVEC) and N-phenylmaleimide (PMI), successfully proceeded through selective vinyl and alternating polymerization to obtain copolymers having the maleimide unit in the main-chain and the five-membered cyclic carbonate group in the side-chain. The structure of these copolymers was analyzed in detail using NMR, IR, and UV-Vis methods. The UV-Vis spectra supported the tautomerization of the maleimide unit based on the solvent effect and the alternating and/or homo sequence constructed depending on the monomer feeds. Furthermore, these copolymers exhibited sensitive and reversible color changes based on acid–base switching not only in solution but also in the solid-state. In particular, the color change in the solid-state occurred immediately after exposure to the amine vapor.

The reversible capture–release behaviors of CO2 by imidazoline derivatives bearing several 2-substituents were investigated under dry conditions containing a very small amount of water. The imidazoline having a cyclic guanidine moiety only captured CO2 quantitatively, and then the cyclic guanidine derivative gave the guanidinium bicarbonate by CO2 fixation together with a slight amount of water. In contrast, the imidazolines bearing n-butylthiol and n-pentyl groups never captured CO2 even with the addition of an equimolar amount of water. Furthermore, the binding structure between CO2 and the cyclic guanidine derivative was studied in detail by elemental analysis, FTIR-ATR, solid-state NMR, TGA, and DFT calculations in order to predict the CO2 capture–release mechanisms depending on the imidazoline structure.

Vinyl ethylene carbonate (VEC) derivatives bearing aromatic moieties were prepared by the catalyzed addition of carbon dioxide (CO 2 ) to butadiene monoxide (BMO) derivatives. The radical polymerization of the VEC monomers was carried out in bulk and solution by using a radical initiator, and those produced polymers were analyzed in detail by IR, NMR, and MALDI-TOF mass methods. These results indicated that radical polymerization of VEC derivatives proceeded through the selective vinyl fashion without depending on the substituents and solvents. Furthermore, the chain transfer reaction occurred easily in NMP and the produced polymer had the NMP moiety in the polymer terminal. The radical polymerization of the bifunctional monomer also proceeded through the vinyl fashion together with the chain transfer reaction in NMP and produced the gelation polymer. Electron-withdrawing of the substituents influenced the thermal property of the produced polymer and bifunctional polymer also obtained the high thermal stability than monofunctional polymer. In this report, the polymerization behavior and property of VEC derivatives bearing aromatic groups was summarized systematically.

The position of the methoxy group in a poly(n-methoxy-2-ethynylnaphthalene) (PnMeO2EN) was found to control the helical pitch of the &pi, conjugated polymer in the solid state. These PnMeO2ENs were stereoregularly synthesized using an Rh-complex catalyst in ethanol or toluene as the solvent. The helical structure in the solid phase was confirmed by conventional analytical methods, namely diffuse reflective ultraviolet&ndash, visible light (UV&ndash, Vis) and Raman spectroscopies, X-ray diffraction, and 13C cross-polarization magic angle spinning NMR spectroscopy, together with molecular mechanics calculations, because the as obtained polymers were insoluble in common solvents. The color of poly(6-methoxy-2-ethynylnaphthalene) (P6MeO2EN) (yellow or red) depended on the polymerization solvent, whereas no such dependency was observed for the yellow-colored P7MeO2EN and P8MeO2EN. The helical structures energetically optimized by molecular mechanics indicate that the red- and yellow-colored P6MeO2ENs form contracted and stretched helices, respectively. Due to the relatively unconstrained rotations of the 6-methoxynaphthyl moieties, the methoxy groups in P6MeO2EN are less sterically hindered along the helical axis. On the contrary, P7MeO2EN and P8MeO2EN have stretched helices due to the considerable steric hindrance imparted by their methoxy groups. The thermal cis-to-trans isomerization of P6MeO2EN in the contracted-helix form required a somewhat higher temperature than that of the stretched helix.

In this study, poly(oxyethyl propiolate)s (POP)s featuring various oxyethylene derivatives are synthesized using a [Rh(norbornadiene)Cl]2 catalyst. In particular, POPs featuring the normal oxyethylene chain in the side-chain exhibit excellent yields and high molecular weights in methanol and N,N-dimethylformamide at 40 &deg, C, compared with poly(n-alkyl propiolate)s (PnAP)s. The high reactivity of the oxyethyl propiolate (OP) monomers is clarified by considering the time dependences of the polymerization yields of OPs and alkyl propiolates (Aps). Furthermore, the monomer structure and intermediate conformation of the Rh complex are optimized using Density Function theory (DFT) methods (B3LYP/6-31G** and B3LYP/LANL2DZ) and a polymerization mechanism is proposed.

We have proposed an islanding detection method using the harmonic current as an active signal. In particular, in order to inject the active signal efficiently, we have proposed a method to synchronize the harmonic voltage caused by the active signal of DG with the harmonic voltage caused by the harmonic current of the load. To verify the validity of the proposed methods, we performed the simulation by PSCAD/EMTDC and the calculation by circuit theory. We clarified that the synchronous injection can be greatly reduced the islanding detection time.

The radical copolymerization of phenyl vinylethylene carbonate (PVEC) with various vinyl and cyclic monomers successfully proceeded through selective vinyl polymerization. In particular, compared with that of the other vinyl and cyclic comonomers, the copolymerization with the N-substituted maleimides (NMI) exhibited high yield and molecular weight without dependence on the N-substituents, due to construction of a charge-transfer complex between PVEC (electron-donor) and NMI monomers (electron-acceptors). IR and UV-vis spectra of these copolymers suggested that the alternating polymerization proceeded between PVEC and NMI monomers, and also indicated that the malemide moiety formed an enolate tautomer in the presence of sufficiently strong basic reagents. The solution of these copolymers was red in color in basic solvents due to the formation of the enolate tautomer, and the solution color changed with a high sensitivity to acid–base switching. These copolymers also exhibited high thermal stability resulting from the maleimide moiety contained within the main-chain.

SUMMARY It is important that photovoltaic (PV) systems detect islanding caused by power system faults to ensure electrical safety. Thus we propose a novel islanding detection method which detects the harmonic impedance by injecting harmonic currents synchronized with the exciting current harmonics of the pole transformer. For the case in which an induction motor load is included in the load system, basic experiments on islanding detection and simulation analysis are conducted to verify the effectiveness of the proposed method.

A helical π-conjugated poly(N-isobutyl-3-carbazole acetylene), P(iBCzA) was stereoregularly prepared using an [Rh(norbornadine)Cl]2–triethylamine catalyst in toluene at 25 °C to determine the detailed geometrical and spatial structures in a tetrahydrofuran (THF) solution and the solid phase. P(iBCzA), which has a bright orange color, was obtained in a yield of 90%. The 2D NMR spectrum of P(iBCzA) in THF-d8 at 50 °C indicated that an extraordinarily extended helix was produced. The WAXS pattern of P(iBCzA) showed the formation of a tetragonal crystal packed with a remarkably stretched cis–transoid (RESTCT) helix similar to that observed in the solution state. This RESTCT helix was confirmed not to be an energetically stable but a metastable structure using MMFF94 program. The solid phase UV–vis spectrum of P(iBCzA) showed the formation of a radical cation called a polaron because of the very large red shifts compared to that observed in solution without the doping.

When large penetration of the distributed generators (DGs) such as photovoltaic (PV) systems is growing up in grid system, it is important to quickly prevent islanding caused by power system fault in order to ensure electrical safety. We propose a novel active method for islanding prevention by harmonic injection synchronized with exciting current harmonics of the pole transformer in order to avoid mutual interference between active signals. We confirm the validity of the proposed method by performing the basic tests of islanding by using a current source superimposed the harmonic active signal. Further, we carry out the simulation using PSCAD/EMTDC, and verify the fast detection of islanding.

The stereoregular polymerization of phenylacetylenes with a para-(ethylene oxide)-methylether: p-O(CH2CH2O)mCH3 (m = 1 and 2) using a [Rh(norbornadine)Cl]2 – triethylamine catalyst was performed at 25 °C for 0.5 h to afford the corresponding helical bright-yellow and dark-violet polymers, P1Y and P2V, respectively. The diffuse reflective UV–vis spectra of P1Y exhibited a λmax at 470 nm, unlike the broad peak of P2V. The wide angle X-ray scattering (WAXS) pattern of P1Y was assigned to the columnar hexagonal crystals (CHC)s on which the stretched cis–transoid helices of P1Y are packed. The bent position of the 2C O bond in p-O1CH22CH2 O 3CH3 was deduced from these crystals. In contrast, the WAXS pattern of P2V demonstrated the formation of a CHC with contracted cis–cisoid helices. The small peak at d = 3.4 A for P2V was assigned to a π-stacking between each benzene ring and/or helical backbone. Their stable geometrical structures, helical diameters, and bent position calculated using the MMFF94 program agreed with those estimated using WAXS.

SUMMARY With increasing penetration of distributed generators such as photovoltaic (PV) systems in distribution systems, it is very important to quickly detect islanding caused by power system faults in order to assure electrical safety. We have developed a nonlinear magnetizing characteristics model of pole transformers for use in analyzing islanding prevention in PV systems. Basic experiments on the islanding detection were performed for verification of the proposed model. Analytical results obtained by the proposed model agreed well with experimental results.

The Rh-catalyzed polymerization of 2 - ethynylnaphthalene ( 2EN ) using ethanol or toluene solvents afforded helical poly(2 - ethynylnaphthalene)s (P2EN)s, i.e., yellow-colored P2EN( Y ) and red-colored P2EN( R ) in good yields, respectively. The diffuse reflective UV–vis (DRUV–vis) spectra of P2EN( Y ) and P2EN( R ) in the solid phase showed broad absorption peaks at 445 nm and 510 nm, respectively. These helical and its crystal structures were investigated using wide angle X-ray scattering (WAXS), resonance laser Raman, and molecular mechanics calculation using MMFF94 force field. Based on these analyses, we found that P2EN( Y ) was composed of stretched cis-transoid helices and P2EN( R ) was composed of contracted cis-cisoid helices in which form intramolecular π -stacking by ca. 3.4 A in distance between neighboring naphthyl rings. Furthermore, the contracted helix was energetically more stable than the stretched helix. The P2EN( Y ) changed to a red-colored polymer, P2EN( Y-R ), by immersion in toluene. This P2EN( Y-R ) completely coincides with the P2EN( R ) in its crystal structure and DRUV–vis spectrum.

SUMMARY As distributed generators (DGs) such as photovoltaic (PV) systems are increasingly used in distribution systems, quick prevention of islanding caused by power system failure is essential to assure electrical safety. Various islanding protection methods have been used practically, but the conventional active systems tend to increase the detection time, because mutual interference occurs between active signals due to asynchronous states. A new active islanding detection method, the frequency feedback method with step reactive power injection, also has the possibility of extending the detection time in the so-called perfect balance area (PBA). Thus we propose a novel method of islanding-prevention by harmonic injection synchronized with the exciting current harmonics of the pole transformer. We performed an experimental study using prototype inverters equipped with the proposed method. We have shown the feasibility of detecting islanding quickly and reliably, even if the islanding state is in the PBA. The experimental results demonstrate that mutual interference does not occur due to asynchronous states between active signals, and also that the proposed method is applicable to islanding detection system in clustered installation of PV systems.

Highly stereoregular polymerisations of p-n-octyphenylacetylene (pOcPA) were performed using a [Rh(norbornadiene)Cl]2-triethylamine catalyst in ethanol at −20 and 25 °C to afford yellow and orange polymers, Poly(Y) and Poly(O), in yields of 64 and 99%, respectively. The XRD patterns of Poly(Y) showed a hexagonal columnar crystal with a contracted cis–cisoid helix, HexaPoly(Y)CC. The XRD pattern of Poly(O) matched that of Poly(Y) when heated to 80 °C. The heat treatment of HexaPoly(Y)CC at 100 °C generated two tetragonal crystals: Tetra1Poly(R)CC, containing contracted cis–cisoid helices, and Tetra2Poly(R)CT, containing stretched cis–transoid helices. The helical diameters of HexaPoly(Y)CC before and after heat treatment were estimated using XRD and were consistent with the results of MMFF 94 calculations, although the n-octyl alkyl chains of HexaPoly(Y)CC and Tetra2Poly(R)CT did not have linear alkyl chains; a bend in the chains was confirmed by 13C CP-MAS NMR. When HexaPoly(Y)CC was heated to 100 °C in the solid phase, the λmax in the diffuse reflective UV-vis spectra shifted from 448 nm to 565 nm. Furthermore, the endothermic transition for HexaPoly(Y)CC occurred at 100 °C in the DSC trace. Therefore, these data corroborated the assertion that HexaPoly(Y)CC thermally converted into Tetra1Poly(R)CC and Tetra2Poly(R)CT.

p-n-Heptylphenylacetylene (pHepPA) was stereoregularly polymerized in n-hexane at 25 °C using [Rh(nbd)Cl]2 catalyst (nbd: norbornadiene) and NEt3, affording the purple-red Poly(R) in 97% yield. A 80 °C heat treatment transformed Poly(R) to the black Poly(B). The Poly(R) X-ray diffraction (XRD) pattern revealed a hexagonal crystal structure comprising contracted cis-cisoid helices [HexaPoly(R)CC]. The 80 °C heat treatment generated two tetragonal crystals: TetraPoly(B)CC containing contracted cis-cisoid helices and TetraPoly(B)CT containing stretched cis-transoid helices. The helical diameters before and after heat treatment were estimated using XRD and were consistent with molecular mechanics calculations (MMFF94 force field method). When heated at 80 °C in the solid phase, the λmax in the diffuse reflective UV–vis spectra of HexaPoly(R)CC shifted from 482 to 560 nm. Additionally, an endothermic transition occurred in the HexaPoly(R)CC differential scanning calorimetric trace at ∼80 °C. Therefore, these data corroborated the assertion that HexaPoly(R)CC thermally converted to TetraPoly(B)CC and TetraPoly(B)CT. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5177–5183

A chiral substituted acetylene, (s)-2-octyl propiolate, was stereoregularly polymerized using a catalyst, [Rh(nbd)Cl]2, at 40 °C in methanol to give the corresponding helical polymer, Ps2OcP. The changes of (1)H and (13)C NMR spectra in line shapes and splitting patterns were consistently interpreted in terms of restricted rotation around the ester O-*C bond, ~O-*C(ε)H(ε)(R)~, R = a branched CH(ε)3 in the ester side chains rather than the helix inversion with the aid of a 3-site jump model. Three peaks due to the branched methyl H(ε) proton and its C(η) carbon observed at 0 °C suggested the formation of three rotamers called A, B, and C, based on the presence of the contracted helix and stretched helix forms that have an intrinsic helical pitch. Furthermore, an accordion-like helix oscillation (HELIOS) along the main chain axis was proposed to explain the temperature dependence spectral changes observed in (1)H and (13)C NMR, UV-vis, and circular dicromism (CD) spectra. The temperature dependence UV-vis and CD spectra of Ps2OcP corroborate the presence of contracted and stretched one-handed helix sense polymers in solution in which the helical pitches and their persistence lengths depend on the temperature.