Study On The Time Mechanism And Model Of Polystyrene Fluid Relaxation

Relaxation time is one of the basic properties of viscous elastic materials,which is one of the basic properties of the adhesive elastic material,which is the time required to transition from one equilibrium state to another under external force.The relaxation characteristics of the viscous elasticity of polymer melts,especially the relaxation time,have an important effect on product performance,and the existing polymer material stereotypes have residual stress,low dimensional accuracy and easy deformation.Due to the complex and variable structure of polymer materials,the stress-strain relationship in the melt state is not adapted to the heck's law of elastic elements or to the law of viscous ness of viscose components.There is no well-recognized well-established viscoelasticity model and theory that can best simulate the mechanical behavior of viscous elastic materials and accurately characterize relaxation time.Therefore,the study of relaxation time mechanism and model in the fluid state of polymer mucous elastic material has broad prospects.In this study,the motion mechanism of PS fluid state is studied based on the widely used polystyrene(PS)polymer.The physical model of polystyrene fluid state is constructed,and the change of relaxation time under external force is expressed by mathematical analysis.Based on the measurement parameters such as PS molecular chain structure parameters and aggregate state structure parameters,a mathematical model of the relaxation time is constructed in the fluid state of PS macromolecular chain,based on the process conditions set by the outside world.The main research work is to carry out experimental research,the instrument to measure the characterization of PS molecular chain structure,aggregation state structure and other parameters.The average molecular weight of 8 different grades PS was measured using a gel chromatograph,and the ratio of weight-to-average molecular weight to data molecular weight was worth to dispersion D.The same sex determination of PS was made by using Fourier Transform Infrared Spectroscopy(FT-IR).The thermal performance of PS is measured using thermal reanalysis(TG)and differential scanning gauge(DSC)to determine the processing temperature area of different grades PS,the number of binding points((?)),the orientation(F),etc.The main research work is based on the experimental findings,theoretical and model research.According to the existing experimental phenomena,the motion mechanism hypothesis in PS fluid state is put forward.To construct a physical model of the large molecular chain fluid under the external force,with the increase of external force stoic effect(temperature increase,speed increase),the state of molecular chain movement changes,the energy E,molecular chain gap v(free volume),the molecular chain segment motion unit,and the relaxation time changes.Combined with the study of the theoretical knowledge of materials science,the microstructure parameters of the material and the conditions of external force steam,the mathematical model of macro factor relaxation time in fluid state is constructed.This study can be simple and fast to characterize the change of relaxation time,indicating that relaxation time is coupled by many factors.The main research work is to apply the experimental relaxation time to the model fitting analysis,select The Brabender torque rheometer secret practice cavity molten polystyrene to measure relaxation time.Set a constant speed(n)40 r/min.To is equal to the glass temperature Tg plus 100?,the experimental temperature range T0? to(T0+20)?,the temperature gradient T is 5?,do temperature single-factor experiment.Set the constant temperature to T0?,selected speed n from 30 r/min to 60 r/min,relay gradient 10 r/min,do the speed single factor experiment.The relaxation time under different experimental conditions is obtained,and the mathematical model is compared with the actual measurement,and the fit effect is better.This study of physical mathematical models can guide the design of polymer materials and molding process,so that their motion units in the fluid state to fully recover,reduce residual stress,improve the comprehensive performance and dimensional accuracy of the product after curing molding.The same method is applicable to other polymer materials and is of great significance to the development of polymer materials.