Dynamic Monte Carlo Simulations Of The Effect Of One-dimensional Nanofiller On The Crystallization Behavior Of Copolymers And Cyclic Polymers

Polymers have attracted widespread attention of researchers due to their unique molecular structure and excellent properties,and their related industries have gradually become an important pillar of the national economy.The addition of nanofillers can significantly change the crystallization behavior of polymer materials,and then improve the physical and mechanical properties of polymer materials.This modification method has been widely used in industry.However,due to the diversity of polymer materials,the microscopic mechanism of the effect of nanofillers on the crystallization of different polymers is not fully understood,which makes it difficult to systematically interpret many experimental results and limits the effective design and application of polymer nanocomposites.Therefore,it is important to study the crystallization mechanism of different polymer systems added with nanofillers both in academia and industry.In this paper,dynamic Monte Carlo simulations were performed to investigate the crystallization behavior of different polymer systems(including random copolymers,block copolymers and cyclic polymers)filled with one-dimensional nanofiller.Specific research includes the following:1.Dynamic Monte Carlo simulations of crystallization induced by one-dimensional nanofiller in random copolymer solutions.Dynamic Monte Carlo simulations are used to study the effect of the one-dimensional nanofiller and non-crystallizable comonomer content on the crystallization behavior of random copolymers.Simulation results suggest that the addition of nanofiller can significantly accelerate the nucleation rate and increase the final crystallinity.Furthermore,changes in the content of non-crystallizable comonomer can also affect the crystallization process and the final crystalline morphology.The nanofiller can induce the formation of nanohybrid shish-kebab structures in the copolymers with low comonomer content.However,in the copolymers with very high content of non-crystallizable comonomer,the presence of a large number of comonomers without the ability of parallel arrangements hinders the formation of nanohybrid shish-kebab structures.The simulation results help people understand the microscopic evolution of the crystal structure induced by the one-dimensional nanofiller in the random copolymer solution,thus guiding the corresponding experimental design.2.Dynamic Monte Carlo simulations of crystallization induced by one-dimensional nanofiller in block copolymer solutions.The effect of one-dimensional nanofiller on the crystallization behavior of crystalline-amorphous diblock copolymers is studied by dynamic Monte Carlo simulations.Simulation results suggest that nanofiller can induce the formation of a novel nanohybrid epitaxial brush structure.In this condition,with the nanofiller as a center,the crystallizable segments are adsorbed on the surface of the nanofiller and orient along the long axis of the nanofiller,while the non-crystallizable segments wrap in the outermost layer.During the formation of this hierarchical structure,the orientation of local crystallizable segments along the long axis of the nanofiller,as well as the local microphase separation between crystallizable and non-crystallizable blocks,both occur prior to crystallization.The simulation results provide new ideas and methods for the design and development of more complex nanohybrid structures.3.Dynamic Monte Carlo simulations of the effect of microphase separation on the crystallization behavior of block copolymers filled with one-dimensional nanofiller.The effect of microphase separation on the crystallization behavior of crystalline-amorphous diblock copolymers is studied by dynamic Monte Carlo simulations.During crystallization,crystalline morphology is codetermined by the competition between segmental orientation perpendicular to microphase interfaces dominated by microphase separation and that along the direction of the long axis of the nanofiller controlled by interfacial interaction.As the repulsive interaction between different blocks is strengthened,the competition between microphase separation and interfacial interaction is intensified,eventually leading to an increase in crystallization rate and a degradation in crystalline morphology.The simulation results provide theoretical guidance for choosing the appropriate interaction strength in actual production,and help people achieve effective control of the final crystal structure of the crystalline-amorphous diblock copolymers.4.Dynamic Monte Carlo simulations of crystallization induced by one-dimensional nanofiller in cyclic copolymer solutions.The effects of nanofiller,molecular chain length and molecular chain topology on polymer crystallization behavior are studied by dynamic Monte Carlo simulations.Simulation results suggest that the filled cyclic polymers exhibit higher melting temperature,higher crystallization temperature and faster crystallization rate than the analogous linear polymers of identical chain length,especially in the systems with relatively shorter chains.Based on the Thomson-Gibbs equation,the difference in the melting point between the cyclic and linear polymers under different chain lengths is theoretically analyzed,and the dependence of the ratio of the melting point of the linear polymers to that of its cyclic analogs on chain length is derived.In addition,nanohybrid shish-kebab structures can form in all systems during isothermal crystallization,while the thickness of kebabs formed by the cyclic chains is greater than that formed by the linear chains.The simulation results establish the relationship between molecular chain length,molecular chain topology and crystallization behavior,which is helpful to help people prepare polymer materials with controllable structure and properties.