Preparation And Properties Of Cellulose Based Vitrimer With Dynamic Ester Bonds

The Vitrimer materials contain reversible covalent networks that can be rearranged under the stimulation of external conditions.The rearrangement process does not cause the change of crosslink density.Compared with traditional thermosetting plastics,Vitrimer materials can be mendable and recyclable,they are expected to solve the problems that traditional thermoset plastics owned such as difficult to recycle.Therefore,Vitrimer materials are receiving more and more attention.As a cheap and readily available biomass resource,cellulose has the characteristics of good biocompatibility and biodegradability,and it is of great significance to solve the problem of insufficient fossil resources.In this paper,cellulose derivatives containing carboxyl groups were used as the main materials,and bisphenol A diglycidyl ether was used as the curing agent,cellulose-based Vitrimer materials were prepared by esterification.The preparation conditions were optimized,the mechanical properties and thermocompression properties of the materials were studied.In this paper,cellulose acetate phthalate containing carboxyl group was used as the main material,and bisphenol A diglycidyl ether was used as the curing agent.A film containing dynamic ester bonds called CAP-DGEBA was prepared by esterification.The solvent resistance test showed that the material had good solvent resistance,it showed that the material has formed a three-dimensional network structure.Thermogravimetric analysis showed poor thermal stability of the material.Differential scanning calorimetry analysis found that the material has no obvious glass transition temperature,the material had no significant remodeling performance.Using microcrystalline cellulose and succinic anhydride as raw materials,succinylated cellulose with different degrees of substitution was prepared by three methods,then succinylated cellulose was used as the main raw material,and bisphenol A diglycidyl ether was used as the curing agent.A film containing dynamic ester bonds called CESA-DGEBA was prepared,but the resulting film had cracked.This may be related to poor dissolution of succinylated cellulose in organic solvents;the material had no thermocompression properties.Finally,the films containing dynamic ester bonds called CAP-SA-DGEBA were prepared with cellulose acetate phthalate as the main material,bisphenol A diglycidyl ether as the curing agent,and a small amount of succinic anhydride.The infrared spectrum characterization of CAP-SA-DGEBA showed that the epoxy group peak disappeared,the characteristic peak of succinic anhydride disappeared,and the ester carbonyl peak appeared,indicating that the esterification reaction was successfully carried out in the reaction system.Thermogravimetric analysis found that the thermal decomposition temperature of CAP-SA-DGEBA was increased by more than 100 ? compared with CAP.Different scanning calorimetry analysis showed that the material had a significant glass transition temperature,and its value changed with the curing temperature and time.The solvent resistance test found that the material swelled in the organic solvent and had good resistance to the organic solvent.Stress relaxation can occur in CAP-SA-DGEBA.Thermal expansion test found that CAP-SA-DGEBA had a topology freezing transition temperature.Dynamic mechanical property test found that the glass transformation temperature of CAP-SA-DGEBA was 73 ?.The material can be reshaped by thermocompression,and the mechanical properties of the material can be basically maintained after reshaping.