Background / Context / Abstract:

 Plastic is used in many products because of its low cost and high processability. However, due to the fact that they are made from crude oil, an exhaustible resource, and the environmental pollution caused by their production and disposal, plastics have become a worldwide problem, and the movement toward plastic-free living is gaining momentum. However, plastics are an essential part of our lives. We aim to create a society where it is acceptable to use polymers and a society in harmony with polymers by developing plastics from a material and manufacturing method with low environmental impact—namely, sulfur and room temperature synthesis.

 Sulfur polymers can be made from sulfur, of which seven million tons are disposed every year, and contribute to building a sustainable society (SDGs). In addition, its high capacitance and refractive index, which are not found in carbon polymers, make it a next-generation polymer that is attracting attention for applications in cathode materials for batteries and lenses. Sulfur polymers have therefore attracted attention in recent years because of their ability to create highly functional sulfur polymers while achieving the SDGs.
However, since the existing sulfur polymer synthesis requires high temperatures (180°C), we were faced with the dilemma of consuming fossil fuels and generating CO2 to synthesize sulfur polymers, which were intended to achieve the SDGs. Considering the entire life cycle of sulfur polymers, it was clear that the environmental impact of the synthesis was a bottleneck for the social implementation of sulfur polymers. This problem was solved by establishing a room temperature synthesis method for sulfur polymers. The sulfur polymers prepared through this synthesis method were found to have lower emissions of carbon dioxide (CO2) and toxic gas (hydrogen sulfide), and almost no odor compared with existing sulfur polymers. The establishment of this low environmental impact synthesis method, which had been a bottleneck in social implementation, has enabled the development of functional materials such as lithium sulfur batteries, self-healing materials, and adhesives, taking advantage of the characteristics of sulfur.

Technology Overview:

World’s first introduction of the concept of sequential polymerization in sulfur polymer synthesis
 Sulfur polymers are commonly synthesized via chain polymerization. On the other hand, the carbon polymers we use are synthesized via sequential polymerization as well as chain polymerization, and are applied to various materials such as clothing and adhesives. Furthermore, the advantage of sequentially polymerized polymers is that they can be synthesized at room temperature. Our idea was that if we could establish a synthesis method for sulfur polymers through sequential polymerization, we would be able to synthesize new sulfur polymer materials, solving the environmental impact of synthesis, which had been a bottleneck for social implementation of sulfur polymers. Through trial and error, we succeeded in synthesizing the world’s first sequentially polymerized sulfur polymer, a sulfur-containing epoxy cured product, by using an unconventional method of using water-decomposable monomers in the presence of water.

Benefits:

Developed a room temperature synthesis method for sulfur polymers that could only be synthesized at high temperatures (180°C or higher)
 By achieving room temperature synthesis, we have reduced the amount of carbon dioxide (CO2) generated in the manufacturing process by 75% and the amount of poison gas (hydrogen sulfide) by more than 99% compared with sulfur polymers synthesized at high temperatures. This has enabled mass synthesis (100 g scale). In addition, the odor of the resulting sulfur polymer was reduced by 75%, which is similar to typical plastics.

Significant contribution to SDGs and carbon neutrality
 Unlike existing plastics, sulfur polymers can be produced primarily from sulfur, not crude oil, making a significant contribution to fossil fuel conservation and carbon neutrality. Furthermore, since sulfur is a waste, it can contribute to building a recycling-oriented society.

Potential Applications / Potential Markets:

Creation of lithium-sulfur batteries with low environmental impact (used as cathode materials and electrolytes)
The development of the room temperature synthesis method for sulfur polymers enables us to fabricate lithium-sulfur batteries with a significantly lower environmental impact than before. The theoretical capacity per weight of lithium-sulfur batteries is 10 times higher than that of existing lithium-ion batteries, so there are high expectations for their use in mobile devices and as in-vehicle batteries. It is also possible to reduce their weight, so they can be applied to areas such as drones and flying cars that will support the next-generation mobility society.

Creation of self-healing materials
A characteristic of the developed sulfur polymer is that it can be restored even if damaged. This characteristic allows for self-healing properties when added to plastics, and is expected to make materials maintenance-free.

Development of functional adhesives (easily dismantled adhesives and adhesives for dissimilar materials)
Sulfur polymers (1) decompose easily and (2) blend easily with other materials. Therefore, we can expect to see adhesives that can be attached and removed as desired, as well as adhesives for dissimilar materials such as metal and plastic.

State of Development / Opportunity / Seeking:

・Available for exclusive and non-exclusive licensing
・Exclusive/non-exclusive evaluation for defined period (set up for options)
・Collaborative/supportive research

※Seeking
1. Development partner
2. Licensing　

IP Status:

PCT applied in Japanese

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