Study on Interfacial Effect by Molecular Dynamics Simulation and Processing Equipment of Micro-nano Laminating Functional Composites
Author:Shi Mei Nong
Supervisor:zhang you chen yang wei min
Micro-nano laminating composites have been widely used and concerned in many fields,especially in optical,electrical,mechanical and other special functional properties.For multilayer structures of polymer,the lamellar geometry provides parallel confinements for the polymers,which would lead to the dramatic change of their microstructures,distinct from those in bulk.Microlayered co-extrusion technology is a rapid and effective method for preparing micro-nano laminating composites,which has been widely used in industrial production.In this paper,we first summarized the research status of the micro-nano laminating extrusion technology and its key principles(torsion laminating),and the performance and application of micro-nano functional composites.Based on the central idea of multidisciplinary crossover,we proposed a new research method for the interfacial effect of micro-nano laminating composite in the polymer processing for the first time,and developed a new production line for microlayered co-extrusion composite.The main work is as follows:(1)In the process of polymer molding,the effect of the interface on the properties of PE and PP-based microlayer polymer materials were investigated by means of molecular dynamics simulation.The interface diffusion and bonding behavior of PE multilayers were investigated,and the micro-structure of PP multilayers was also explored.At the same time,the interface diffusion depth and coefficient,the degree of interfacial integration,the molecular order parameters and distribution at the interface,the degree of chain entanglement and interpenetration,the end-to-end distance and the radius of gyration were taken as the means of characterization.The degree of interfacial integration is defined by the author for the first time.(2)And the influence of interface on the orientation of graphene in PE-based microlayered composites was studied by means of molecular dynamics simulation.The whole process was characterized by molecular order parameter,compared with the homogeneous(or bulk)materials.It is helpful to further understand the the influence of microstructure of the microlayer composites on the material properties and to optimize the micro-nano laminating extrusion process.And the experimental study was carried out on the basis of the theory.Based on the principle of torsion laminating,the graphite/PE-based microlayer composites were prepared by micro-nano laminating extrusion technology.The effects of different layers and different graphite particles on the mechanical,dielectric properties and crystallization behavior of the composites were investigated.At the same time,SEM,DSC,tensile tester and dielectric strength tester were taken as the means of characterization.It could provide some theoretical basis for the application of strong film.(3)In the process of polymer molding,the effect of interface on the properties of PMMA/PET/PC microlayered composites was investigated by means of molecular dynamics simulation.The relationship between interface microstructure,the degree of interfacial integration and interface roughness and optical properties of the composites was also discussed.The molecular order parameter,the end-to-end distance,the radius of gyration and the degree of interfacial integration were taken as the means of characterization.On the basis of this,the design and manufacture of the unequal-thickness torsion laminating device was carried out.At the same time,PMMA/PET functional microlayered composites with unequal-thickness were prepared.The reflectivity of 512 layers optical thin film to infrared spectrum was discussed,which provided the theoretical basis for the application of energy in the building.In a word,the multilayer structure model was established by molecular dynamics simulation,and the theoretical mechanism of micro-nano laminating polymer materials was studied.The interfacial effect and application of micro-nano laminating functional composites were further explored.The optical film processing and production line was successfully developed.In the basic theory of multilayer structure,the microlayer interface effect of single-component or multicomponent was deeply understood from the molecular scale,which was combined with the practical application,and such as the mechanical,dielectric,optical high-performance and multi-functional microlayered composite was successfully developed.It provides new ideas and new methods for the development of polymer processing and new polymer materials.