Experimental Study And Theoretical Simulation Of Structure And Properties Of High-density Polyethylene

For a long time, high-density polyethylene (HDPE), such as tank materials made of HDPE, has been monopolized by imported materials. Silica-supported Phillips catalyst is the core catalyst for the production of HDPE. The development of domestic tank materials lags far behind since the lack of association between the molecular chain structure and the performance further results in the lack of the theoretical and technical support for the improvement of the catalysts and process. In recent years, due to the rapid development of computer technology, people have been aware of the importance of molecular dynamics (MD), which is a powerful tool for theoretical and experimental investigation. This paper studies the relationship between the structure and crystallinity of the polymer chain from the experiment and theoretical simulationsIn this paper, temperature rising elution fractionation is used to analyze the monomer distribution of the three tank materials; At the same time, simulation of the dynamics of polyethylene which was very close to the real system under vacuum is built in this paper as well. The effects of molecular weight, contents of short branch chain and the length of short branch etc. are studied to understand the correlation of the structure and crystallinity of the polymer chain from theoretical simulations. Two types of the tank materials are used as models for molecular simulation. It was found that monomer distribution has a substantial effect on the non-isothermal crystallization. The crystallinity of the short chain branch in the low molecular weight is less than the short chain branch distribution in the high molecular weight, which is consistent with the experimental results.