- To enhance the mechanical properties of PP/lignin composites, a filler-focused approach is emphasized to maximize the synergistic effect of interfacial reinforcement.
This composite exhibits excellent light and thermal aging resistance due to the antioxidant effect of lignin, contributing to extended material lifespan and improved recyclability. - We are engaged in the synthesis and modification of various inorganic compounds, as well as the synthesis and modification of organic substances and polymers, with the goal of developing their practical applications.
- As shown in the figure, the clay–biopolymer nanocomposite enhances rigidity, strength, and toughness simultaneously.
- We are developing materials that contribute to environmental purification and resource recovery, including user-friendly environmental remediation materials such as clay/fiber composite filters and clay particle columns.
Environmental Circulation Composite Material Group
STAFF
Group leader
Group members
AIM and GOAL
Solving global environmental problems has become an urgent priority. The Environmental Circulation Composite Materials Group is dedicated to developing fundamental and applied technologies that contribute to resource recovery and recycling systems. Specifically, our focus is on converting waste into recyclable, valuable materials, as well as conducting research on technologies that enhance the value of natural resources.
Additionally, we are actively engaged in the development of high-performance composite materials that are not only highly functional but also environmentally friendly, making optimal use of natural resources.
APPROACH
- Development of Recycled Materials：
In order to promote the widespread use of biomass, we are working on the development of composite technology to overcome the issues related to their physical properties. We are also conducting research on using inorganic materials synthesized from natural minerals and exhaust CO2 as reinforcing fillers (Fig.1 a). - Development of Circular Functional Materials：
We are developing fast ionic conductors using highly sulfonated polymers with low environmental impact and highly water-retentive particles. Our goal is to apply them in hydrogen production/utilization devices (Fig.1 b). - Theoretical Approach：
We combine advanced theoretical analysis and experimental demonstrations to thoroughly understand the complex properties of materials (Fig.2).
FIG 1 Development of resource-utilization functional composite materials: (a) Development of high-performance bio-polymer composite materials filled with high-function fillers obtained from CO2, (b) Fast ionic conductors with highly sulfonated polymers and highly water-retentive particles.
FIG 2 Development of technology for reducing the volume of contaminated soil through theoretical analysis and demonstration experiments.
(STEP-1) The desorption treatment of radioactive Cs from contaminated soil using the molten salt-acid treatment method.
(STEP-2) Soil regeneration and pollucite inclusion of radioactive Cs-volume reduction.
TAMURA, Kenji / Group leader
mail：TAMURA.Kenji@nims.go.jp
Development of Resource-Circulating High-Performance Composite Materials
Overview
- Development of functional materials by utilizing "common materials" (such as natural minerals and biomass) to effectively harness their hidden properties.
- Manufacturing of lignin-containing thermoplastic composite materials as an alternative to petroleum-based plastics using melt compounding.
- Development of functional clay-biopolymer nanocomposites through clay modification and composite technology, achieving improved strength, toughness, and recyclability.
- Establishment of advanced design technologies for various reinforcing fillers, enhancing functionality through mineral synthesis, surface treatment, and higher-order structural analysis.
- Development of adsorption filters and column packing materials for resource recovery, utilizing layered double hydroxide (LDH) coatings on fiber surfaces and the synthesis of rosette-like LDH particles.
Characteristics
- Developing manufacturing technologies for filler-reinforced composite materials to overcome the limitations of biomass.
- Developing thermoplastic lignin-based plastic materials as alternatives to petroleum-based plastics.
- Enhancing the mechanical properties of biopolymers—specifically "rigidity," "strength," and "toughness"—through nanocomposite technology.
- Advancing technologies that utilize abundant natural materials, such as synthesizing nanotubular clay minerals, imparting swelling properties to natural mica, and synthesizing minerals from waste resources.
- Developing adsorbent materials for environmental purification and resource recovery, while improving the biomass content and recyclability of plastics.
Major reserch
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Summary
Mineral resources, such as clay minerals, can be transformed into functional materials, including high-performance plastic reinforcement fillers and highly selective adsorbents. Furthermore, by designing composite materials with controlled interfaces and hierarchical structures between reinforcement fillers and biomass materials, it is possible to develop viable alternatives to petrochemical-based plastics.
Enhancing key product attributes such as processability and recyclability facilitates the transition toward resource-circulating and environmentally sustainable materials.
SUEHARA, Shigeru
mail：SUEHARA.Shigeru@nims.go.jp
Theoretical approach to environmental composite materials
Overview
As part of our efforts to develop a recycling society, we are conducting theoretical research into the properties of substances made up of common elements (ubiquitous elements) that are not rare, including natural minerals. Specifically, we aim to reproduce the properties of recycled materials using semi-empirical density functional theory calculations, and to investigate their origins by comparing the results with experimental data.
Density functional theory is a method for calculating the properties of materials based on the arrangement of atoms, and we believe that this theoretical research will lead to the construction of fundamental technologies for the appropriate use and reuse of natural minerals and ubiquitous elements in a recycling-oriented society, as well as improvements in industrial activities such as environmentally friendly resource management and waste reduction.
Characteristics
- High-speed parallel computing using NIMS supercomputer and GPU workstations.
- Revealing atomic behavior in materials (diffusion, chemical reaction, etc.) by various molecular dynamics and the elastic band methods, etc.
- Theoretical reproduction of various observed spectra for elucidating experimental facts.
Major reserch
Interlayer ion exchange reactions occurring in typical clay minerals found in natural soil have been the subject of theoretical calculations. These calculations suggest that radioactive cesium, released by the accident at the Fukushima Daiichi Nuclear Power Plant, which was caused by the earthquake and tsunami on 11 March 2011, is adsorbed more strongly in clay than other typical ions (a).
We also have found a new layered compound "siliborophene" structure made from two common elements, silicon and boron, by theoretically reproducing the distinct phonon vibration spectra, etc. The siliborophene structure shows a unique electronic structure (Dirac cone) and it could lead to the development of new materials made up from ubiquitous elements that originated in graphene and borophene (b).
In addition, we have conducted research to investigate the diffusion (permeation) capabilities of ubiquitous ions in nanosheet membranes that can be applied to new types of ion batteries (c).
Summary
We are conducting theoretical research on materials using models consisting of a few to several hundred atoms, with a focus on semi-empirical density functional calculations.
While the pure theoretical results would be impossible to contribute directly to recycling technology developments, we believe that our approach would play an important role in the analysis stages of basic, applied and demonstration experiments for recycling material research.
KIM, Jedeok
mail：KIM.Jedeok@nims.go.jp
Development of environmentally friendly alternative polymer electrolyte materials
Overview
Climate change requires a stable energy supply on a global scale, and efforts are being made to achieve carbon neutrality by 2050. Amidst the development of various technologies to utilize renewable energy sources such as solar, wind, and biomass that do not emit CO2, hydrogen is expected to lead the way in a new energy paradigm that replaces fossil fuels.
Alternative materials to the fluorine-based polymer electrolytes used in water electrolysis and fuel cells are essential, and we are conducting research into improving the functionality of hydrocarbon-based PPSU electrolytes as a non-fluorine-based electrolyte material.
Characteristics
- Highly sulfonated polymer
- Sulfone crosslinking
- High proton conductivity
- High chemical stability
Major reserch
Engineering plastics, which are hydrocarbon-based polymers, are used in a variety of fields due to their high chemical and thermal stability. We are developing functional electrolyte materials using polyphenylsulfone (PPSU). PPSU has many phenylene groups, which are sites for introducing sulfo groups that can impart high ionic conductivity, and it is expected that the introduction of high sulfo groups will lead to the creation of high proton conductors.
In addition, the use of nanoparticles such as imogolite, nanosilica, and carbon nanodots has high moisture retention, and when introduced into polymer electrolytes, it is possible to maintain the high conductivity of the electrolyte even in high temperature and low humidity conditions. Furthermore, we expect that this will dramatically improve the chemical stability of hydrocarbon-based electrolytes.
We are conducting research into the sophistication of electrolyte materials through the synthesis of polymer electrolyte materials, membrane production, evaluation of the membrane's physical properties, and device evaluation for fuel cells and water electrolysis.
Summary
Achieving carbon neutrality will require breakthrough technological development in a variety of fields.
Among these, the development of hydrocarbon-based electrolytes as an alternative to the fluorine-based electrolyte materials currently used in water electrolysis, fuel cells, etc. is expected to make a significant contribution to the development of innovative materials that will support the hydrogen society of the future.
SAKUMA, Hiroshi
mail：SAKUMA.Hiroshi@nims.go.jp
Development of Environmentally Harmonious Materials Using Natural Resources and Understanding Their Physical Properties Through Mechanistic Insights
Overview
To address urgent environmental problems, I will develop a new material using carbon dioxide gas. I will attempt to synthesize calcium carbonate minerals with various morphologies and use them as reinforcement materials for weak bio-based materials.
I also develop adsorbents for toxic substances using clay minerals, which are ubiquitous in the natural environment and have a low environmental impact.
In addition, the underlying mechanisms of the physical properties of materials will be revealed through various scientific approaches to increase the reliability of materials, strengthen the quality control, ensure safety, and inspire the innovation of new materials.
Characteristics
- Material design based on the theory of crystallography and surface structure
- Analysis of the physical properties of materials from ab-initio to large-scale molecular dynamics simulations
- Measurement of solid-liquid interfacial structures with a resolution of less than 0.1 nm
Major reserch 1
Design of materials with a low environmental impact
- Synthesis of calcium carbonate：
Synthesizing calcium carbonates with various morphologies and sizes as reinforcement materials for weak bio-based materials - Synthesis of clay minerals：
Development of adsorbents based on various clay minerals found on the surfaces of Earth and Mars
Major reserch 2
Analysis and molecular simulations of materials:
Increasing the reliability of materials, strengthening quality control, and inspiring the innovation of new materials.
Our X-ray scattering structural analysis of surface and interfaces, along with molecular simulations, enables us to understand the underlying mechanisms of physical properties of materials. Through these techniques, we have gained knowledge of the specific adsorption sites on adsorbents for toxic elements, the effects of additives on the adsorption and desorption of organic molecules on calcium carbonate surfaces, and the lubrication mechanisms of solid lubricants.
Summary
- Development of reinforcement materials for mechanically weak bio-based plastics using synthetic calcium carbonate crystals with various morphologies
- Development of environmentally low-impact adsorbents using layered clay minerals, which are ubiquitous in natural environments
- Understanding the properties of crystal surfaces and interfaces by using surface-sensitive analytical techniques and molecular simulations for the development of new materials and enhancement of quality control
YAMANE, Ryo
mail：YAMANE.Ryo@nims.go.jp
Development of resource circulation technologies based on the utilization of water, minerals, and pressure
Overview
Water is an indispensable substance in our daily lives and industries and is especially useful as a solvent. Minerals are also effectively utilized as resources such as structural materials and chemical products. By discovering hitherto unknown functionalities of these elements composed of the earth, I will promote low-environmental-load developments.
In these developments, I would like to promote research using high pressure, which has high technical barriers to entry but is an effective parameter to change of physical properties of materials. Through my research, I will also return my technical knowledge of high pressure to society.
Characteristics
- Utilization of chemical reactions involving water in hydrous inorganic solids aiming for change of the physical properties of the inorganic solids
- Anomalous X-ray scattering techniques applying to materials which have complicated structures
- Technical developments of electrical measurement under harsh conditions, high pressure (hundreds of MPa) and high temperature (hundreds of degrees Celsius) aiming for applying my technique of high-pressure electrical measurement to innovative manufacturing processes
Major reserch
- I discovered that dehydration, deprotonation of water, and oxidation of iron occur simultaneously upon heating in hydrous iron(II) phosphate, vivianite. I opened up the possibility of application of the iron phosphate to the lithium-ion battery.
- I discovered ice XIX, the 20th crystal polymorph of ice by using a pressure cell for dielectric measurement, which was newly developed. Now I attempt to apply my own techniques to measure the physical properties of materials under hundreds of MPa and at hundreds of degrees Celsius.
- I have investigated structures of sulfosalt minerals, which are attracting attention as thermoelectric materials, by anomalous X-ray scattering.
Summary
- Development of functionality of hydrous inorganic solids
- Structural investigation of functional minerals
- Technical developments of electrical measurement under high pressure
Fields of Electronic and Photofunctional Materials Research Center
Ultra-wide Bandgap Semiconductors Group
Optical Single Crystals Group