摘要
Polyetherketoneketone(PEKK)is a new evolving polymeric material,and is considered as another important member of the polyaryletherketone(PAEK)family in addition to polyetheretherketone(PEEK).Hot compression molding can be used to compact and consolidate the PEKK products,where the temperature and pressure play key roles to affect the molecular mobility,entanglement and crystallization,and thus the mechanical properties of PEKKs.In this study,a preheating treatment was introduced in the compression molding,and it is found that such preheating is very essential to avoid the formation of crystal FormⅡ,based on the increased chain entanglement.Molecular dynamics simulations revealed that the molecular mobility is always suppressed when a compression is applied.Therefore,by increasing the entanglement via the preheating and maintaining such entanglement in the consequent compression molding,strong and tough PEKK materials were obtained,with a negligible fraction of crystal FormⅡ.
基金
financially supported by the Fundamental Research Funds for the Central Universities(No.2232021G-01)
the National Natural Science Foundation of China(No.51862036)。
