Adjusting And Modeling Of The Dynamic Properties Of Epoxy Vitrimer

Vitrimer as a new type of polymeric materials have been widely studied,since they ideally combine the structural stability,solvent resistance and healable,reprecessable properties that obscuring the line between thermosets and Thermoplastics.Although a series of vitrimers with different dynamic bonds and different matrix materials have been developed in recent years,the research on the key influencing factors and regulatory methods of epoxy vitrimer dynamic properties is still very lacking.Therefore,this paper proposed to regulate the dynamic performance of epoxy vitrimer by changing the orientation of 2D fillers,the content of 2D orientated fillers and the monomer ratio（X）,and studied its influence rule.Specific research contents are as follows:（1）Studying on the influence of two-dimensional packing orientation on the dynamic performance of epoxy vitrimer.The flake graphite oriented composite was constructed in epoxy vitrimer matrix by heat pressure induction.Because of the special arrangement of the filler in the matrix,the existence state of the filler in the two directions of the composite material is completely different,resulting in the difference of its properties in the two directions.The dynamic properties of the composites are affected by different degrees in different directions.The characteristic relaxation time（τ）,activation energy（E_a）and Arrhenius pre-exponential factor（τ₀）all show anisotropy due to the orientation arrangement of the filler.（2）Studying on the influence of two-dimensional oriented filler content on the dynamic performance of epoxy vitrimer.Two series of composite materials were prepared by heat pressure induction and direct mixing and curing respectively.The mechanism of the influence of filler content in different distribution states on the dynamic properties of composite materials was studied in detail.The effect of flake graphite on dynamic properties of force-induced composites is divided into two different forms.The first is the effect of accelerated relaxation caused by the slip between fillers.The second is the relaxation inhibition effect caused by the blocking of network segment movement by the filler.Therefore,the stress relaxation time of the composite materials first accelerates and then slows down with the increase of the content of the filler.However,for the samples with disordered distribution of directly mixed fillers,there is only one inhibiting factor,which is that the filler blocks the movement of the network segment,resulting in the phenomenon that the relaxation time of the composite materials is prolonged with the increase of the content of the filler.（3）Studying on the influence of monomer formula ratio（X）on the dynamic performance of epoxy vitrimer and its model.Based on the theoretical study of vitrimer material dynamic properties in vitrimer materials,a series of mathematical models were established to understand its dynamic properties,predicting and controlling the dynamic behaviors of its exchange reaction.The series of exponential models or functions can be used to easily customize polyester based epoxy glass polymers,while after experimental calibration,similar or corrected exponential models will be developed and applied to more other glass polymer networks.