Team:Nanjing-China/Description

Before our project began, a true story happened to our team member Zhongqi Xu attracted our attention to fire accidents. During a whale watching tour, he witnessed a fire accident in which not only did fierce smoke and burning flames devour a ship but also ignited the tarpaulin of Xu's boat.

Although there was no danger in the end, the boat fire was put out in time and no casualty were caused, this experience of escaping from fire left Xu a deep expression, and initiated our thinking about the fire.Fire, brings human light and energy, along with fear and disasters, smoke, flame, tears.

In the last decades, fire has become a world-wide crucial security issue.

As the saying goes, to forestall is better than to amend. On one hand, the development of reliable fire-retardant materials is the most valid weapon against fire. On the other hand, when firefighters rush into the fire rescue, they also need more protection and guard. Fire clothing, as the focus of continuous improvement in fire protection work, highly requires the development of lightweight, waterproof and breathable fireproof fabrics, which is a significant part that new materials can contribute to for fire safety.

The research and development of fireproof materials has always been a hot spot in the research and development of new materials.In the early stages of the project (2019.12),Our team members investigated webpages of many fireproof material companies and the manager from Gesanghua Paint Company, hoping to provide some help and guidance for the overall idea of the project.

Current Existing Problems

The research and development of fireproof materials has always been a hot spot in the research and development of new materials. Our team members investigated webpages of many fireproof material companies, obtaining a good grasp of the relevant situation in this field.

The results of the preliminary investigation show that traditional fire proof materials cannot meet the various needs of current market, and there are still many pain points that can be improved. At present, the best-selling fireproof materials in the market can be divided into water-based and solvent-based based on the solubility of the coating itself, and can be divided into intumescent and non-expandable based on the foaming performance of the coating. The most common fireproof coatings are mainly inorganic materials represented by calcium carbonate, vermiculite, perlite, and coagulants-resins, flame retardants-ammonium polyphosphate, blowing agents-melamine, solvents-poly Pentyleneerythritol is used as a set of organic materials in a flame retardant system.

Traditional flame-retardant materials still have shortcomings and drawbacks that need to be resolved in many aspects:

First of all, the most critical issue is the environmental problems and pollution of materials. The solvents involved in the production and processing of solvent-based fire-retardant coatings are mainly flammable and explosive liquids containing benzene and alcohols. At the same time, they have certain toxicity and high carcinogenicity. They are the main pollutants in the production and use of coatings. Dust substances and volatile gases involved in fire retardant coatings are another important issue to be faced. Many inorganic materials can cause incalculable pollution if they cannot be properly sealed.

Secondly, the durability of materials is also an issue that cannot be ignored. This material is often used on the surface of buildings, cables, clothing, etc., and the contact surface with the external environment is relatively large. The effects of natural weathering, exposure, rain erosion, and acid-base corrosion in special environments are extremely important for its fire resistance. test. At the same time, many human factors also affect its durability. For example, a fire-resistant garment needs to be able to maintain a certain degree of fire resistance even after repeated washings. If a material cannot achieve good durability, it is difficult to escape the fate of being eliminated.

Moreover, the scalability of the material is not strong, and the application field is narrow. Some materials are relatively stable in nature, but have few surface active groups, or the material structure is difficult to modify... Various reasons make it difficult to properly combine with other materials, making them only applicable to the single field of fire retardant coatings , Can not properly combine with other organic biological macromolecules, the competitiveness of the material will be slightly inferior.

In addition to the above aspects, more superior flame retardancy and fire resistance, thermal stability, material strength and other aspects also need to be further strengthened.

PolyP plus protein equals to PolyP Pro

From this we thought of a new material——polyphosphate, which can be synthesized in vivo. Compared with organic polyanionic biomolecules (nucleic acids), inorganic polyphosphates have the following obvious characteristics:

(1) There is no genetic information involved due to lack of sequence differences;

(2) There is no higher structure due to the monotonic repetition of phosphate.

In the industrial field, commercialized ammonium polyphosphate is often a mixture of orthophosphate and polyphosphate. Polyphosphates have been used in plant phosphate fertilizers and food additives. In addition, another important use of ammonium polyphosphate can also be used as halogen-free, highly effective, non-toxic flame retardant. This is also the focus of our project. Due to its simple structure, polyphosphate can form a relatively dense structure and is very stable.

At present, polyphosphates can be used as fiber materials (paper, wood, fiber fabric), various polymers, refractory building boards, coiled materials, epoxy resins and unsaturated resins, cables and rubbers, plastic materials for electronic devices, etc. Its excellent flame retardant properties greatly aroused the interest of our team members, so our project focused on polyphosphate research.

However, polyphosphate has many innate limitations, such as narrow application range, poor combination ability with other materials, etc. As we know, polyphosphate is strongly negative. Considering that DNA，which is also negative-charged with phosphate group，can bind with histone by electrostatic force (histone binds in the big groove of DNA double helix, protecting DNA in the cell environment), we come up with the idea of combining polyphosphate with organic biological macromolecules similar to histone, so as to improve the properties and application prospect of polyphosphate in many aspects.

Therefore, our team put forward a new concept - "novel organic-inorganic biosynthetic materials". With the help of synthetic biological methods, we propose to replace the traditional chemical synthesis method by engineering bacteria production. For one thing, the contamination problem in the production process of fire-retardant materials could be tackled. For another, combining with organic macromolecules might maintain its excellent fire-retardant ability and achieve additional stable physical and chemical properties. Moreover, it might perform the original functions of biological macromolecules, expanding its wearability, adding fluorescence, and eventually achieve a brandnew breakthrough in material properties.