PP as a polymer consists of long molecular chains with a complex tertiary structure. Among them, according to the chemical structure of molecular chains, linkage and spatial configuration, etc. are divided into the primary structure; molecular chains can change their conformation through the internal rotation of the performance is called the chain flexibility, usually the greater the chain flexibility the easier it is to crystallize, according to the molecular chain flexibility of the differences, such as straight chains, folded chains and helical chains and other morphology composed of the polymer's secondary structure; furthermore, in the secondary structure of the different forms of the molecular chain Further, the combination of different forms of molecular chains in the secondary structure forms an aggregated structure, which is usually divided into a disordered amorphous region and a dense and ordered crystalline region, called the tertiary structure (Aggregate structure).