Microstructure Study In High-density Polyethene

Macromolecules and Polymer are macromolecular compounds(about 10⁴～10⁶) and constituted by many similar and simple units repeatedly connected by covalent bond.Recentl years, the composition of high Polymer developed rapidly,many important Polymer were produced.The structure studied and capabilities improved of macromolecules are very important in application.In practical scientific research,the technique for microstructure is much more improved. In 1932,the US physicist Anderson found positron in studying cosmic ray.Since then,the technology of positron armihilation spectroscopy has been widely used in materials science.Positron Annihilation Lifetime Spectroscopy(PALS) is an original position probing technology.As the antiparticle of electron and microprobe,positron has many advantages than other experimental techniques in the detection of micro-structure of polymer,nano-scale micro-cavity,structural changes and relaxation,surface,interface properties,and blending,the compatibility of copolymers, etc.The free volume of polymer was first proposed by Fox and Flory,and closely related of many physical and chemical properties to the polymer,such as viscosity,viscoelasticity,vitrified transition and plastic yielding,Studying free volume can help us understanding the relation of polymer structure and properties.PALS's small size probe will not have a significant effect to the matter. Positron priorly annihilated in the holes and defects,its life and intensity was closely related to the size of hole and quantity of the free volume.So,PALS is a very useful technology to study the size and concentration of free volume.In this paper,we programmed a positron spectrum analysis program based on Windows system,and sdudied the free volume and microstructure of High-Density PolyEthylene(HDPE). This program has a preferable superiority to study microstructure of same materials.We will summarize the operating principle of PALS,the application and data analysis method of lifetime spectrum.Finally,we introduced the application in polymers,the program structure and analysis in micro-structure and free volume of HDPE.We get differentÏ„₃ and free volume following changed temperature.At last,we will introduce the relationship between the free volume formation and temperature.