Dynamic polymer with dynamic cross-linked structure

Abstract

The invention discloses a dynamic polymer with a dynamic cross-linked structure. Organic boric acid silicon ester bonds are contained on polymer chain skeletons of a cross-linked network and/or on cross-linked link skeletons between polymer chains, wherein the organic boric acid silicon ester bonds are necessary for forming/maintaining a dynamic polymer structure. The dynamic polymer is rich in structure and diverse in properties. By regulating and controlling the structure of a reactant, the dynamic polymers with different properties can be prepared. In addition, due to strong dynamic reversibility of the organic boric acid silicon ester bonds in the polymer, the polymer can exhibit functional characteristics of stimulus responsiveness, self-healing property, recoverability and the like; and besides, due to the presence of the organic boric acid silicon ester bonds, the polymer can also have the energy absorbing effects, and polymer materials can be toughened in a given structure. The dynamic polymer can be used for making shock-absorption cushioning materials, impact-resistance protection materials, self-healing materials, ductile materials and the like.

Description

technical field [0001] The invention relates to the field of intelligent polymers, in particular to a dynamic polymer composed of dynamic reversible covalent bonds and having a dynamic crosslinking structure. Background technique [0002] Dynamic chemistry is an interdisciplinary subject developed by combining supramolecular chemistry and dynamic covalent chemistry in covalent chemistry. Traditional molecular chemistry focuses on stable covalent interactions, while dynamic chemistry focuses on some relatively weak non-covalent interactions and reversible covalent bonds. Among them, supramolecular chemistry is based on non-covalent intermolecular interactions. Compared with traditional covalent bonds, these non-covalent interactions generally have weaker bond energy and are greatly affected by thermodynamics. The formed supramolecular To some extent, the structure is not a stable system, and it is easy to be destroyed, which has caused many restrictions on its characterizati...

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Problems solved by technology

[0004] However, the chemical equilibrium process in traditional dynamic polymers is often slow because it involves the breaking and formation of covalent bonds, and it is often necessary to add catalysts or provide energy from the outside to accelerate the equilibrium process.

In addition, some reversible covalent bonds themselves have certain defects in the actual use process, which limit the use environment and application fields of dynamic polymers.

For example, the traditional transesterification reaction is the earliest reversible exchange reaction used by people, but the conditions of the transesterification reaction are relatively harsh, and generally need to be completed under the conditions of adding alkali and reflux. At the same time, the dynamic activity of the traditional ester bond is poor. The application of dynamic polymers constructed by transesterification has limitations; products based on furan-maleimide Diels-Alder cycloaddition generally require dissociation reactions at high temperatures, and this reaction in organic solvents The process is slow; the imine bond formed by the reaction of primary amine and aldehyde is strongly affected by the pH, which makes it difficult to stabilize such imine bond under normal conditions; the reversible exchange reaction of amino transfer needs to be carried out under the action of special protease; Based on the dynamic reversible bond of the alkoxynitrogen group, the dissociation reaction temperature often has to reach 100-130°C. At the same time, the carbon-centered free radical generated by the dissociation of the alkoxynitrogen group is sensitive to oxygen and high temperature, and the resulting irreversible The bonding will affect the performance of the material; the dynamic polymer containing trithioester group needs to be irradiated by ultraviolet light to undergo dynamic exchange reaction; the disulfide bond in the dynamic covalent bond has better dynamics, and its The exchange reaction can be carried out under low temperature conditions, but the mercaptan itself is less stable, and it will react with the surrounding air to produce continuous oxidation during use, so that the mercaptan content in the reversible system is continuously reduced, which affects the use of materials

The existence of such situations makes it difficult to fully reflect the characteristics of the dynamic reversible covalent bond itself under normal conditions. It is necessary to develop a new type of dynamic polymer so that the dynamic reversible covalent bond in the system can simultaneously satisfy the reversible reaction. Fast speed, mild reaction conditions, and controllable reversible reaction conditions to solve the above-mentioned problems in the prior art

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