Research progress in theoretical calculation of polyimide

At present, the research on polyimides has been more and more deeply, but many variables affect the accuracy of the test results in the process of preparation and testing in the laboratory, such as temperature, pressure, relative molecular weight, molecular weight distribution, aggregation state and so on. It is difficult to analyse and parallelly compare the data. With the development of computer technology, simulation technology has been developed rapidly. Molecular simulation technology has been applied in the research of materials a certain scale to explore the relationship between the structure and properties of polymers (Yang et al. 2006). Using theoretical calculation, each parameter can be well-controlled (Pan et al. 2005). Molecular simulation technology can simulate the real environment of the laboratory and the environment which is difficult to be realised and cannot be realised. Therefore, it is an important method to investigate the performance of polymer materials in different environments by using the method of theoretical calculation (Mei et al. 2009).