Experimental Research And Mechanical Properties Simulation Of Polyamide 66/Heat Resistant Polylactic Acid

Plastic as one of the three major synthetic materials,after one hundred years development has been widely used in aviation,aerospace,home decoration,agriculture,light industry and other industries,it is still developing rapidly,but today the resources and environment load is approaching the limit and the pollution is serious,and "White pollution" and discarded plastic products produced by the plastics industry are one of the reasons.There are a variety of new biodegradable plastics,polylactic acid as a member of its own performance comparable to engineering plastics and the implementation of green development has been widely concerned.Based on the biological base plastic polylactic acid(PLA)and polyamide 66(PA66)engineering plastics as the research object,using molecular dynamics simulation to build different degree of polymerization of PA66/ PLA molecular cell model,energy minimization of molecular model and the structure optimization after reaching balance,compatibility and mechanical properties of blends system simulation;The influence of PLA content on the phase morphology,rheological property,crystallization property,mechanical property and degradation property of PA66/PLA blend system(PLA content is 10%,20%,30%40%,50%)was investigated by injection molding standard sample with the reference of simulation results.In addition,the influence of adding different content of compatibilizer Styrene-Maleic Anhydride(SMA content is 1%,3%,5%,7%,9%)on the performance of the blends system was also investigated.The results showed that: in the molecular dynamics simulation,it was found that PA66 and PLA were difficult form a compatible system by comparing the radial distribution function of different molecular and atomic pairs,and the elastic modulus of PA66/PLA blend system was in line with the increasing trend of polymer blending law.Through the experimental study on the injection sample,the phase morphology of PA66/PLA system showed poor compatibility between the two components.When the PLA content reached 50%,the PLA phase turnde to continuous phase.The rheological behavior test showed that the viscosity of the system decreased with the increase of PLA content,and when the PLA content reached a certain level,the interface slip was easy to occur at high shear rate;In Differential Scanning Calorimeter(DSC),the results showed that the crystallization rate increased and the crystallinity increased within a small range,which was beneficial to improve its mechanical properties.After the mechanical properties test,the tensile strength and elongation at break of the blends system decreased with the increase of PLA content due to the poor compatibility of the components,while the elastic modulus increased.Considering the degradation of biobased plastic PLA,it was found that it did not affect the properties of the material.In addition,in order to improve the compatibility between components,a PA66-SMAPLA alloy with a PLA content of 20% was prepared.Through phase morphology,rheological test and mechanical properties test,the results showed that the addition of compatibilizer SMA greatly improved the compatibility of PA66 and PLA,further reducing the viscosity of PA66-SMA-PLA is good for material processing molding,and when the content of SMA is 3% or more,its tensile strength exceeds that of PA66.