Study On Preparation And Properties Of Multifunctional Shape Memory Polybenzoxazine

As a new type of smart material,shape memory polymer can be programmed into a temporary shape under the specific condition of excitation,and when the excitation is applied again,it will return to the original shape of the memory.Different from the traditional deformation driving device,when the shape memory polymer is excited,the molecular configuration changes to realize the macroscopic shape change,and it is sensitive to a variety of environmental changes,such as heat,light,magnetism,electricity and solution etc.As a newly developed thermosetting resin,benzoxazine has excellent heat resistance,high T_gand mechanical properties.Because benzoxazine has extremely high molecular designability,in recent years,scientific researchers have paid more attention to its modification work.This topic uses the copolymerization reaction of phenol/polyetheramine and phenol/furfurylamine type benzoxazine to prepare a high T_gtriple shape memory polybenzoxazine.Electrically induced shape memory composites are prepared by compounding multi-walled carbon nanotubes.Compared with the conventional thermally driven SMP,the realization of the triple and electro-induced shape memory properties of shape memory polybenzoxazine expands its multifunctional development and application approaches.In this project,phenol/furfurylamine-type(P-fa)and phenol/polyetheramine-type benzoxazine(P-pea)with flexible main chain segments were prepared by a two-step method.Through the copolymerization of the two monomers in different proportions,the resin with improved crosslinking density and excellent thermomechanical properties was prepared.With the increase of the content of P-fa,the shape memory characteristics of the material show that the two separated transition peaks gradually turn into a wide transition temperature range.After testing,it can achieve a good triple shape memory effect,and the fixation rate and recovery rate of the material are above 95%and 99%,respectively.In order to solve the problem of a single driving mode of shape memory polybenzoxazine,conductive multi-walled carbon nanotubes are compounded in the polymer matrix to achieve shape recovery under electric driving conditions.The conductive performance of the composite material system has a sudden change at about7wt.%,indicating that a complete and continuous internal conductive percolation network is formed,and the conductive performance is greatly improved.The composite material with a filling ratio of 10wt.%has a significant improvement in high-temperature oxidation resistance compared with pure resin,and the residual carbon rate at 800°C is increased to 45%.Under the condition of 60V DC voltage,the shape recovery process within 15s can be realized,showing that it's an electrically driven shape memory polymer composite material with good performance.Based on the characteristics of the prepared shape memory polybenzoxazine resin,four deformed corrugated board structures with different cross-sectional forms were designed.The shape memory deformation process of a typical corrugated board is simulated by the finite element analysis method.Due to the material's variable stiffness characteristics,the stress value is kept at a low level.The simulation results of the flexural and vibration characteristics of different structures show that the rectangular cross-section corrugated plate has greater flexural rigidity and fundamental vibration frequency,and it has high structural safety and rationality,showing its great potential in the application of deformed skin structures.