Polymer Journal

Ihara, Eiji

doi: 10.1038/s41428-024-00954-1pmid: N/A

Recent results from the author’s research group on the development of polymer syntheses using diazocarbonyl compounds as monomers are described. A series of new Pd-based initiating systems for C1 polymerization of diazoacetate have been developed, each of which possesses characteristic initiating ability with respect to high-molecular-weight polymer synthesis, tacticity control, and chain end functionalization. The use of functional ester substituents has led to polymers with unique properties and functionalities in comparison to their vinyl polymer counterparts [poly(alkyl acrylate)] with the same ester substituent. Polycondensations using bis(diazocarbonyl) compounds as monomers are also described. By utilizing a variety of reactivities of a diazocarbonyl group, a series of three-, two-, and single-component polycondensations have been realized, affording new polymers whose chemical structures cannot be attained by any existing method for polymer syntheses.

Tanaka, Shinji

doi: 10.1038/s41428-024-00965-ypmid: N/A

Solid-state NMR is one of the most powerful analytical methods for the structural characterization and dynamics of polymers. Owing to its intrinsically low signal sensitivity, however, analysis of trace chemical species supported on polymers remains challenging. Solid-state NMR with dynamic nuclear polarization (DNP-NMR) has recently attracted attention as a highly sensitive NMR measurement method for analyzing polymers. We recently investigated DNP-NMR for insoluble polymers, particularly cross-linked polymers, engineering plastics, and polymer-supported catalysts, and achieved high NMR signal sensitivity at a routinely accessible level. In this focus review, we present case studies on DNP-NMR measurements for a wide range of polymers.

Uto, Takuya

doi: 10.1038/s41428-024-00966-xpmid: N/A

Crystalline polysaccharides are abundant in nature and can be transformed into highly functional materials. However, the molecular basis for the formation of higher-order structures remains unclear. Computer simulation is an advanced tool for modeling macromolecular structures, and the atomistic simulations provide valuable information on the crystalline polysaccharides. Fiber deformation, crystalline transition, and novel nanostructures of cellulose were characterized through molecular dynamics simulations and density functional theory calculations of models of molecular chain sheets extracted from the crystal structure of the cellulose polymorphs. Extended ensemble molecular dynamics simulations were applied to analyze the artificial crystal structure of non-natural amylose analog polysaccharides, revealing the hexagonal packing of double helices through the self-assembly of molecular chains dispersed in aqueous solution. Dissolution simulations of the cellulose and chitin crystalline fibers revealed that the anions of ionic liquids, with their solvation power, played a key role in the cleavage of intermolecular hydrogen bonds in the crystal structure, whereas the cations contributed to irreversible molecular chain dispersion. The good correlation between the actual solubility of polysaccharides and the predicted number of intermolecular hydrogen bonds prompted the development of a platform that combined simulations and machine learning for high-throughput screening of solvents for cellulose and chitin.

Tamate, Ryota

doi: 10.1038/s41428-024-00969-8pmid: N/A

Owing to the digital revolution and growing emphasis on sustainability, the demand for innovative electrochemical devices, such as flexible and wearable sensors, energy-harvesting devices, and high-capacity secondary batteries, has been increasing. Alongside this, various high-performance gel electrolytes with excellent mechanical and electrochemical properties have been developed. This focus review presents our recent research on enhancing the mechanical properties of gel electrolytes and their application in lithium secondary batteries. It discusses the efforts made to achieve self-healing ion gels, which utilize ionic liquids as the electrolyte solutions. Additionally, the review covers the application of functional gel electrolytes in next-generation lithium secondary batteries. It focuses particularly on improving the cycling performance of lithium metal anodes, which are considered the very promising anode material. Moreover, the future prospects of functional polymer gel electrolytes have been discussed in this review.

Abe, Naoya; Numata, Keiji

doi: 10.1038/s41428-024-00973-ypmid: N/A

Plant mitochondria are essential for energy production and male sterility. The genetic transformation of plant mitochondria has attracted attention due to its potential to improve the mitochondrial function and agricultural productivity of energy crops. However, mitochondrial genome editing has been challenging because the delivery of the macromolecules needed for genome engineering to mitochondria has not been established until now. In addition, the genome editing efficiency in mitochondria needs to be improved as much as possible due to the lack of a selection marker for mitochondria. To achieve mitochondrial modification, the proteins and/or DNA/RNA needed for genome editing should be delivered to mitochondria precisely and efficiently. Peptides have been utilized to improve delivery efficiency to plant mitochondria. Thus, we herein review advances in delivery technologies related to plant mitochondrial genome engineering using various functional peptides.

Suzuki, Seigo

doi: 10.1038/s41428-024-00962-1pmid: N/A

Advanced communication technology using millimeter waves (mmWaves) requires new polymeric materials with low dielectric properties to minimize signal transmission losses. The dielectric polarization of polymers, including electronic, vibrational, orientational, ionic, and interfacial contributions, as well as the water molecules absorbed within them, is strongly related to their dielectric properties in the mmWave region. This has led to the emergence of liquid crystal polymers (LCPs) and fluoropolymers as candidate materials for mmWave communication. However, their poor secondary processability and adhesion to copper wiring often limit their practical application. This focus review describes two types of thermoplastic films developed via formulation design technology for mmWave communication. A crystalline polyaryletherketone-based film, compounded with a plate-like, low-polarity filler and blended with miscible noncrystalline polymers to control the crystallization behavior, exhibits a low transmission loss capability comparable to that of LCPs. Additionally, this film offers solder reflow heat resistance, a low coefficient of thermal expansion (CTE), and excellent multilayer processing capabilities at low temperatures, making it suitable for use in multilayer substrates for mmWave communication applications. A polyolefin-based film demonstrates ultralow dielectric properties comparable to those of fluoropolymers and strong adhesion to copper foil. Furthermore, this film offers customizable functionalities, including laser processability, transparency, a low CTE, and flame retardancy, enabling its application in flat, flexible cables and transparent antennas. Owing to their unique characteristics, these films are promising candidates for mmWave communication materials.

Hirai, Takayuki

doi: 10.1038/s41428-024-00977-8pmid: N/A

Composite materials are widely used in many industrial products because they combine the properties of organic and inorganic materials. This review focuses on the property modification of composite materials where polymer blends are used as matrices to obtain functional composites. Polymer blends can be fabricated via the physical process of melt mixing; thus, they have good scalability. However, poor material design criteria compared with those of polymer synthesis are critical defects in polymer blending. To address this problem, we focused on the multiscale phase separation in polymer blends. Polymer blends can be divided into three categories according to their phase morphology: immiscible, miscible, and reactive. They exhibit characteristic behaviors that depend on their morphology. We propose a novel material design concept to combine polymers with different phase morphologies to obtain a combination of modification mechanisms. To provide specific examples, two previous studies on the modification of carbon- and glass-fiber-reinforced plastics were summarized. One study involves improving the hygrothermal resistance of carbon-fiber-reinforced polyamide by incorporating both miscible and immiscible components into the polyamide. The other study involves fabricating transparent glass-fiber-reinforced polyamides by investigating miscible and reactive blends.

Yonekawa, Morio; Kimura, Hajime; Ohtsuka, Keiko; Shimokawaji, Tomohiro

doi: 10.1038/s41428-024-00964-zpmid: N/A

The thermal curing reactions of p-tert-butylcalix[n]arenes (Cn) (n = 4, 6, and 8) with 1,3-phenylenebis(2-oxazoline) (PBO) were performed. The obtained thermosets were characterized to determine the relationships between the ring size of the calixarenes and the properties of their network polymers. The samples were cured by heating at 160 °C and 180 °C for 1 h each and then at 200 °C, 230 °C, and 250 °C for 2 h each without a solvent and catalyst. For comparison, a corresponding linear four-nucleus novolac (L4) was cured with PBO under the same conditions. Dynamic mechanical analyses of the thermosets revealed that the glass transition temperature (Tg) increased in the following order: L4/PBO < C4/PBO < C8/PBO < C6/PBO. Model reactions with a monofunctional oxazoline compound indicated that the final crosslinking degree of the network polymers increased with increasing ring size. Conversely, the cyclic structures became increasingly rigid as the ring size decreased. Because of its moderate reactivity and rigidity, the network polymer derived from C6 exhibited the highest Tg.

Ishimaru, Ryotaro; Suzuki, Yasuhito; Matsumoto, Akikazu

doi: 10.1038/s41428-024-00967-wpmid: N/A

Poly(dialkyl fumarate)s (PDRFs), which are produced by the radical polymerization of dialkyl fumarates, are highly transparent amorphous polymer materials with excellent heat resistance, mechanical, and optical properties. The physical properties of PDRFs with a rigid poly(substituted methylene) structure discontinuously change at their β transition temperature (Tβ) because of restricted local molecular motion, including the rotation of substituents in the side chain. In this study, we performed a radical polymerization of symmetric and asymmetric dialkyl fumarates, including 4-tert-butylcyclohexyl esters with a fixed cycloalkyl conformation, to clarify the thermal and optical properties of the produced PDRFs. The Tβ value, refractive index, and density of the PDRFs increased with the introduction of the 4-tert-butylcyclohexyl group. Based on the wide-angle X-ray scattering (WAXS) measurement results, we analyzed the spontaneous aggregation of the PDRF chains in the solid state to discuss their density and optical properties in detail.

Zhao, Jiaxin; Hu, Hongliang; Jiang, Dawei; Jin, Yujie; Li, Chun; Luo, Feng

doi: 10.1038/s41428-024-00956-zpmid: N/A

Wollastonite (W)/carbon black (CB)/chlorinated polyethylene (CPE) conductive composites were prepared via melt compounding using CB and wollastonite as fillers and CPE as the matrix. To analyze the internal structure of the material and examine how changes in crystallinity affect the positive temperature coefficient (PTC) behavior of the composites, several characterization techniques were employed. These methods included scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry. Each method provided insights into the structural adjustments and their implications for the electrical properties of the material. Special attention was given to the influence of the wollastonite content on the electrical conductivity of the composites. The results demonstrated that the lowest room-temperature resistivity (1.66 Ω·cm) was achieved with 15 wt.% wollastonite doping after 1 h of heat treatment. At the same time, the PTC strength increased to 4.7.