RESEARCHIntroduction
Since the current materials creation industry is a mass energy-consuming industry, it is important to create and research and develop low environmental impact materials with a view to extending the life of polymeric materials and recycling. The future issue is environmental symbiosis, and low-environmental-load and high-efficiency energy materials for future-type energy are also expected. Biodegradable plastics, natural polymers, and natural fiber materials are examples of low-environmental-impact and high-efficiency energy materials for future-type energy. If we can reduce the use of petrochemical materials and replace them with natural polymers and natural fiber materials, it will be environmentally friendly and help prevent global warming.
In addition, fundamental materials science is needed to enable quantitative evaluation and design of polymeric materials for the development of new materials and higher functionality. Our laboratory conducts research based on "nanostructure control" and "property evaluation," which has attracted the attention of many companies from the viewpoint of functional material development and long-term durability. The results obtained in our laboratory will contribute not only to the development of polymer materials science but also to new technologies.
01
Nano-Porous Group
As polymer materials are thinned, they exhibit different properties from those in the bulk. In particular, ultra-thin films of several to several tens of nanometers in thickness increase surface activity and improve adsorption and other properties. In addition, nanofabrication by the top-down method or nanopore formation by the bottom-up method can be used to create new functionalities.
In our laboratory, we fabricate polymer thin films by spin-coating and casting methods to form nanopores and to evaluate and control nanostructures.
【Papers】
1. "Development of highly oil-absorbent polylactic-acid microfibers with a nanoporous structure via simple one-step centrifugal spinning", Linmei Zhang, Chieko Narita, Yuki Himeda, Hidekazu Honma, Kazushi Yamada*, Separation and Purification Technology, Volume 282, Part B, 2022, 120156. (https://doi.org/10.1016/j.seppur.2021.120156)
2. "Nanofabrication of high throughput 30 nm hole 2D arrays by a simple visible laser ablation technique", Kazushi Yamada*, Chieko Narita, Ramanujam Kumaresan, Takuya Shinohara, Mitsuhiro Terakawa, and Yasuyuki Tsuboi, Applied Surface Science, Vol.420, pp.868-872, 2017. (http://dx.doi.org/10.1016/j.apsusc.2017.05.243)
02
Natural Polymer Film Group
In recent years, research using biodegradable polymer materials and natural polymer materials has been active from the viewpoint of environmental issues, oil depletion issues, and even microplastic issues. In our laboratory, we have conducted research on thin films using silk fibroin and lacquer.
On the other hand, unlike synthetic polymers, natural materials require know-how in the process of making solutions and films. Therefore, we are trying to develop a simpler and reagent-free method of thin film fabrication. We are also evaluating the effects of external factors such as light and heat on the surface and internal structure of natural polymer thin films, with the aim of creating new nanocomposite materials.
【Papers】
1."Plasticizing effect of lignin on urushi in bio-composite films", Chieko Narita, Yoko Okahisa, Kazushi Yamada*, Polymer, Vol.161, pp.49-54, 2019. (https://doi.org/10.1016/j.polymer.2018.11.063)
2."Influence of the type of Urushi and substrate on the chemical and physical properties of Urushi films", Chieko Narita, Kazushi Yamada*, Progress in Organic Coatings, Vol.105, pp.183-189, 2017. (http://dx.doi.org/10.1016/j.porgcoat.2017.01.004)
3."Influence of the finishing methods of Urushi products on degradation", Chieko Narita, Yutaro Shimode, Kazushi Yamada*, Progress in Organic Coatings, Vol.101, pp.379-384, 2016. (http://dx.doi.org/10.1016/j.porgcoat.2016.07.024)
03
Film Sealing Group
The packaging of confectionery and other food products that we usually buy or eat without much thought are made by laminating films together using the heat sealing method. However, film bonding mechanisms have not been adequately studied, and many unclear aspects remain. As a result, under certain operating conditions, the sealed portion of the bag may break, or the film itself may tear.
Our laboratory focuses on microstructural changes and crystallization in the sealing area of plastic films. We perform heat sealing using various plastic films and evaluate the effects of sealing time, temperature, and seal bar surface shape on the sealing properties using spectroscopy and microscopy.
【Papers】
1."Molecular Orientation Effect of Heat-Sealed PP Film on Peel Strength and Structure", Kazushi Yamada, Ken Miyata, Reiichi Konishi, Kiyomi Okada, Tetsuya Tsujii, Advances in Materials Physics and Chemistry, 2015, 5, 439-446.
2."A novel methodology for peel strength enhancement of heat-sealed oriented polypropylene/cast polypropylene film by tensile cyclic loading", Kazushi Yamada*, Ken Miyata, and Ramanujam Kumaresan, Materials Chemistry and Physics, Vol.187, pp.112-118, 2017. (http://dx.doi.org/10.1016/j.matchemphys.2016.11.054)