다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

비만아 부모의 돌봄 경험: q 방법론

Dielectric polymer nanocomposites are rapidly emerging as novel materials for a number of advanced engineering applications. In this Review, we present a comprehensive review of the use of ferroelectric polymers, especially PVDF and PVDF-based copolymers/blends as potential components in dielectric nanocomposite materials for high energy density capacitor applications. Various parameters like dielectric constant, dielectric loss, breakdown strength, energy density, and flexibility of the polymer nanocomposites have been thoroughly investigated. Fillers with different shapes have been found to cause significant variation in the physical and electrical properties. Generally, one-dimensional and two-dimensional nanofillers with large aspect ratios provide enhanced flexibility versus zero-dimensional fillers. Surface modification of nanomaterials as well as polymers adds flavor to the dielectric properties of the resulting nanocomposites. Nowadays, three-phase nanocomposites with either combination of fillers...

Recent Progress on Ferroelectric Polymer-Based Nanocomposites for High Energy Density Capacitors: Synthesis, Dielectric Properties, and Future Aspects.

Radical Polymerization and Copper(0) Mediated Polymerization): From Fundamentals to Bioapplications Cyrille Boyer,*,†,‡ Nathaniel Alan Corrigan,‡ Kenward Jung,‡ Diep Nguyen,‡ Thuy-Khanh Nguyen,‡ Nik Nik M. Adnan,†,‡ Susan Oliver,†,‡ Sivaprakash Shanmugam,‡ and Jonathan Yeow†,‡ †Australian Centre for Nanomedicine, and ‡Centre for Advanced Macromolecular Design (CAMD), School of Chemical Engineering, University of New South Wales, Sydney 2052, Australia

Copper-Mediated Living Radical Polymerization (Atom Transfer Radical Polymerization and Copper(0) Mediated Polymerization): From Fundamentals to Bioapplications

Materials Synthesis Athina Anastasaki,†,‡ Vasiliki Nikolaou,† Gabit Nurumbetov,† Paul Wilson,†,‡ Kristian Kempe,†,‡ John F. Quinn,‡ Thomas P. Davis,†,‡ Michael R. Whittaker,†,‡ and David M. Haddleton*,†,‡ †Chemistry Department, University of Warwick, Library Road, CV4 7AL, Coventry, United Kingdom ‡ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash Institute of Pharmaceutical Sciences, Monash University (Parkville Campus), 399 Royal Parade, Parkville, Victoria 3152, Australia

Cu(0)-Mediated Living Radical Polymerization: A Versatile Tool for Materials Synthesis

For potential application in high energy storage capacitors with high energy density and low energy loss, three sets of poly(vinylidene fluoride-co-trifluoroethylene-co-chlorotrifluoroethylene) [P(VDF-TrFE-CTFE)] grafted with poly(methacrylic ester)s, including poly(methyl methacrylate) (PMMA), poly(ethyl methacrylate) (PEMA) and poly(butyl methacrylate) (PBMA) copolymers, are designed and investigated carefully. Due to their intermediate polarity, relatively high glass transition temperature, and excellent compatibility with PVDF chains, the poly(methacrylic ester) segments introduced could not only dramatically weaken the coupling interactions of oriented polar crystals, but could also accelerate the reversal switching of polar crystal domains along the applied electric field, which leads to well hindered remnant polarization. As a result, the displacement–electric field (D–E) hysteresis behaviors of the graft copolymers could be tuned from typical ferroelectric to either antiferroelectric or linear shape under high electric field. Meanwhile, significantly reduced energy loss and effectively improved energy discharging efficiency were obtained. Compared with PMMA and PBMA, PEMA with intermediate polarity and grafting length exhibits more suitable confinement of the F–P transition of P(VDF-TrFE-CTFE), and thus more desirable energy storage properties are observed in the resultant copolymers. These findings may help to deeply understand the ferroelectric nature of PVDF based fluoropolymers and design new energy storage capacitor materials with high discharged energy density and low energy loss.

Tuning phase transition and ferroelectric properties of poly(vinylidene fluoride-co-trifluoroethylene) via grafting with desired poly(methacrylic ester)s as side chains

Recently, tuning the normal ferroelectric performance of poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-co-TrFE)) to either relaxor ferroelectric or anti-ferroelectric behavior by confining the relaxation of ferroelectric crystal domains physically or chemically has attracted considerable interest to achieve high discharged electric energy density (Ue) and low energy loss (Ul) for energy storage applications in high pulse capacitors. To improve the dielectric and energy storage properties as well as reduce the energy loss induced by the ferroelectric relaxation of P(VDF-co-TrFE), unsaturation containing P(VDF-co-TrFE) films were uniaxially stretched after crosslinking with peroxide in this work. P(VDF-co-TrFE) containing unsaturation was synthesized via controlled hydrogenation and dehydrochlorination of commercially available poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-co-CTFE)). The properties of the films obtained were characterized with differential scanning calorimetry (DSC), X-ray diffraction (XRD), dielectric constant and electric displacement–electric field (D–E) hysteresis loop measurements. Compared with the as-cast and as-crosslinked films, the stretched films exhibit a significantly enhanced dielectric constant, breakdown field (Eb > 500 MV m−1) and Ue but depressed energy loss. This could be attributed to the enhanced film quality, optimized crystalline properties, improved orientation uniformity of crystal domains as well as accelerated ferroelectric relaxation induced by the crosslinking and mechanical stretching. The best performance was achieved for the stretched film with a dielectric constant of 15 at 1 kHz, a relatively high Ue of 17.5 J cm−3 and a low energy loss of about 30% at 575 MV m−1.

Significantly improving dielectric and energy storage properties via uniaxially stretching crosslinked P(VDF-co-TrFE) films

The discovery and prosperous growth of synthetic polymers have presented both significant advantages and daunting challenges in the last century. To address the issues of environmental pollution an...

Advances, Challenges, and Opportunities of Poly(γ-butyrolactone)-Based Recyclable Polymers

Ring-opening polymerization is one of the three polymerization methodologies, together with addition polymerization and polycondensation. Poly(ester), poly(2-oxazoline), poly(phosphoester), poly(ether), poly(amino acid) and nylon 6 are mainly synthesized via ring-opening polymerizations of their corresponding cyclic monomers. To obtain well-defined and cost-effective polymers, the combination of ring-opening polymerization and microflow technology has drawn great interest from both academia and industry. This article highlighted recent progress in continuous flow ring-opening polymerizations. Lactone, lactide, 2-oxazoline and cyclic phosphate were assessed as cyclic monomers in consecutive order. The challenge and outlook for microfluidic ring-opening polymerization were also discussed.

Xin Hu

Papers

Tuning phase transition and ferroelectric properties of poly(vinylidene fluoride-co-trifluoroethylene) via grafting with desired poly(methacrylic ester)s as side chains

Significantly improving dielectric and energy storage properties via uniaxially stretching crosslinked P(VDF-co-TrFE) films

Advances, Challenges, and Opportunities of Poly(γ-butyrolactone)-Based Recyclable Polymers

Continuous flow ring-opening polymerizations

Continuous flow SET-LRP in the presence of P(VDF-co-CTFE) as macroinitiator in a copper tubular reactor