Study On The Structure And Stress-Strain Curve Of Polymer/Nanoparticle Composite System

The dispersion behavior and spatial distribution of nanoparticles(NPs)in ring polymer melts are explored by using molecular dynamics(MD)simulations.As polymer–NP interactions increase,three general categories of polymer-mediated NP organization are observed,namely,contact aggregation,bridging,and steric dispersion,consistent with the results of equivalent linear ones in previous researches.In the case of direct contact aggregation among NPs,the explicit aggregation–dispersion transition of NPs in ring polymer melts can be induced by increasing the chain stiffness or applying a steady shear flow.Results further indicate that NPs can achieve an optimal dispersed state with the appropriate chain stiffness and shear flow.Moreover,shear flow can not only improve the dispersion of NPs in ring polymer melts but also control the spatial distribution of NPs into a well-ordered structure.This improvement becomes more evident under stronger polymer–NP interactions.When study the stress-strain of the system,the influence of the ring polymer chain stiffness and shear flow on the stress-strain are researched.Under the weak polymer-NP interactions,the system appears better stress when shear flow and chain stiffness are considered at the same time in polymer chains.Furthermore,the effect of the concentration of NPs on the stress of the linear/ring polymer system in equilibrium was studied.The stress of the system is affected by the concentration of NPs and polymer-NP interactions: under weak polymer–NP interactions,the stress decreases with the increase of the concentration of NPs;under the medium polymer–NP interactions,the concentration of NPs increases,the stress first increases,then stays stable within a certain concentration range,and finally decreases;under the high polymer–NP interactions,the stress first increases and then decreases,appear transition points.Compared with the ring polymer system,the linear polymer system shows better stress when increasing the concentration of NPs due to its advantages of configuration.Finally,we conclude that the stress transition point concentration of the system increases with the increase of the polymer–NP interactions,and under the same interaction,the stress transition point concentration of the linear chain system is greater than that of the ring chain system.Our research provides an effective way for the design and manufacture of high-performance polymer nanocomposites.