Study On The Blending Process Of GF-reinforced PA And Its Morphology And Properties Under Volume Elongational Flowing Deformation

Glass fiber reinforced polyamide is a kind of thermoplastic with excellent comprehensive properties such as high strength,high toughness,good dimensional stability,wear resistance,self lubrication and corrosion resistance.It is widely used in daily life and industrial production.However,the blending process of traditional glass fiber reinforced polyamide is dominated by screw extrusion,which is based on the shear rheological forming method.Because of the strong shear force in the flow field,continuous glass fibers are to a great extent cut off and the fiber dispersion is poor,which affects mechanical properties and product appearance.At the same time,thermo-mechanical processing time for screw mixing is long,and the polyamide resin is likely to degrade during the process,which affects long-term thermal oxidative aging,creep and aging behavior.Traditional screw processing methods and equipment can not effectively solve these problems.In this paper,the new method of polymer forming based on volume elongational flowing deformation is used to prepare glass fiber reinforced polyamide.A double axis eccentric rotor extruder is applied to produce glass fiber reinforced polyamide 6/66 under volume elongational flowing deformation;process cycle and mechanism,glass fiber length retention,surface appearance,basic mechanical properties and constitutive properties are discussed,glass fiber orientation is studied by CT scanning and simulation.This paper is of important academic value providing new ideas and the theoretical basis for industrial production and application of glass fiber reinforced polyamides;enriching theory and practice of glass fiber reinforced polyamide molding.This is the first time a double axis eccentric rotor extruder based on volume elongational flowing deformation has been used for the preparation of glass fiber reinforced polyamide 6/66.Under the influence of the volume elongational flowing deformation field,the glass fiber is dispersed evenly in the resin.Through optimization of the extrusion process,the glass fiber retention in the polymer can reach 750 ?m,which is 2 times higher than that of twin screw extruders,the impact property more than doubles,and a good product appearance can be obtained.Advantages of the double axis eccentric rotor extruder are the short thermo-mechanical processing time and low energy consumption.Volume elongational flowing deformation plays an essential role in avoiding degradation and maintaining viscosity and processing stability of the polymer resin during processing.Compared with polymers prepared by twin screw extruders,the polymers prepared by the double axis eccentric rotor extruder exhibit better resistance to yellowing,long-term thermal oxidative aging,creep and fatigue.In this paper,CT scanning is applied to study glass fiber orientation of glass fiber reinforced polyamide prepared by double axis eccentric rotor extrusion,and the orientation of fibers in different thickness directions within the product is discussed.Moldflow software is used for analysis,its most fully developed RSC glass fiber model is selected,a reasonable interaction coefficient Ci and K factor are chosen in order to predict the glass fiber orientation more accurately,and provide practical guidance for the application of this kind of glass fiber reinforced material.