Part two

In addition to the same activity of azide groups, acyl azide groups could be changed into isocyanate groups by Curtius rearrangement with the heating or under UV light. The isocyanate groups are highly reactive functional groups and can react with hydroxyl and amino groups to form urethane and urea structures, therefore, acyl azide chemistry has been paid much attention in organic synthesis and organic reactions. With the development of polymer science, polymers scientists have shown much interest in the synthesis and application of acyl azide polymer. However, due to the instability of acyl azide monomers to heat and light, we noticed that quite a few papers were published on preparation of polymer by chain polymerization of unsaturated acyl azides as monomers. Therefore, the development of acyl azide polymers synthesized by free radical polymerization of acyl azide monomers is an important and challenging topic. If the living free radical polymerization of acyl azide monomers could be achieved, not only can the molecular weight be controlled with narrow molecular weight distribution, but also a promising strategy can be developed for design and synthesis of the well-defined novel acyl azide polymers with different architectures, such as block, graft, and star shapes. In recent years, our laboratory has been committed to the study of new acyl azide polymers and for the first time we have reported the synthesis of azido polymers via controlled/living free-radical copolymerization of acryl azido monomers under ⁶⁰Co γ-ray irradiation. According to the relationship between the property and the structures, we have been seeking to find the more stable vinyl acyl azide monomers at room temperature and new polymerization methods for acyl azide monomers.

J. Polym. Sci. Part A: Polym. Chem., 45, 2609–2616 (2007)

Soft Matter, 7, 3956-3962 (2011)

Synthesis、Polymerization of the Azide and Acyl Azide Monomers and the Applications
Azide groups are high energy groups and reactive groups, which can be transformed into a variety of functional groups. So the chemistry of azides has attracted great attention of chemists, and organic azides have become very useful intermediates in synthetic chemistry. With the development of the polymer science, the synthesis and application of the azide polymers have also attracted much interest of polymer scientists, and synthesis methods were got rid of the stale and brought forth the fresh. Azide polymers are used widely as high energetic materials, cross-linking materials and the materials for surface modification. At the earlier development stage, azide polymers were commonly prepared by chemical modification of polymers or by cationic ring-opening polymerization of cyclic ether azides. However, these approaches have some disadvantages, azide content in the polymer produced by chemical modification couldn’t be controlled very well, and ionic polymerization requires stringent reaction conditions such as high purity of monomers and high vacuum techniques. With the rapid development of the living radical polymerization especially RAFT polymerization and the further understanding of the azides, azide polymers with novel structure have been synthesized through the living radical polymerization. We have been trying to develop facile and effective strategies for the preparation of azide polymers, and living free radical polymerization has been first successfully used to prepare different azide polymers by γ-ray initiation in our lab. In this thesis, we have designed and synthesized a series of new vinyl azide monomers based on the relationship between molecular structure and chemical property. We have explored the stability and polymerization character of the new vinyl azide monomers, and developed the new methods for the synthesis of the azide polymers. The application research of azide polymers have also been carried out as cross-linking materials and surface modification materials, and functional polymers. *Macromol. Rapid Commun.* 2009, 30, 442-447. *J. Polym. Sci. Part A: Polym. Chem.* 2010, 48, 1348-1356. *Langmuir* 2010, 26, 7529-7534. *Polymer* 2010, 51, 1940-1946.

In addition to the same activity of azide groups, acyl azide groups could be changed into isocyanate groups by Curtius rearrangement with the heating or under UV light. The isocyanate groups are highly reactive functional groups and can react with hydroxyl and amino groups to form urethane and urea structures, therefore, acyl azide chemistry has been paid much attention in organic synthesis and organic reactions. With the development of polymer science, polymers scientists have shown much interest in the synthesis and application of acyl azide polymer. However, due to the instability of acyl azide monomers to heat and light, we noticed that quite a few papers were published on preparation of polymer by chain polymerization of unsaturated acyl azides as monomers. Therefore, the development of acyl azide polymers synthesized by free radical polymerization of acyl azide monomers is an important and challenging topic. If the living free radical polymerization of acyl azide monomers could be achieved, not only can the molecular weight be controlled with narrow molecular weight distribution, but also a promising strategy can be developed for design and synthesis of the well-defined novel acyl azide polymers with different architectures, such as block, graft, and star shapes. In recent years, our laboratory has been committed to the study of new acyl azide polymers and for the first time we have reported the synthesis of azido polymers via controlled/living free-radical copolymerization of acryl azido monomers under ⁶⁰Co γ-ray irradiation. According to the relationship between the property and the structures, we have been seeking to find the more stable vinyl acyl azide monomers at room temperature and new polymerization methods for acyl azide monomers. *J. Polym. Sci. Part A: Polym. Chem., 45, 2609–2616 (2007) Soft Matter*, 7, 3956-3962 (2011)