Study on Improvement of Tensile Strength of Polyimide Film

A study of mechanical properties is of importance for investigation of phase aggregation states,structure,and interactions in polymer chains which determine the suitability of a polyimide film in a specific application.In this paper,the methods to improve the mechanical properties of polyimide film based on pyromellitic dianhydride (PMDA) and 4,4’-oxydianiline (ODA) have been researched.When triphenyl phoshpate is added,the tensile strength of polyimide film is obviously improved.When the addition is the weight of polyimide film’s 3%,the tensile strength is increased 1.8 fold compared to the original.By infrared analysis,the structure of polyimide film added triphenyl phoshpate has not been changed,and its tensile strength is approaching to Kapton H film’s.The tensile strength of polyimide film will also be affected by the temperature of de-solvent and the heating way of thermal imidization.When the process of de-solvent is kept at 90℃,or the heating rate of thermal imidization is 8℃/min,or the top temperature of thermal imidization is 375℃,or the heating way of two steps is used,the tensile strength of polyimide film can be improved too.In a word,we have found that many factors have influenced on the tensile strength of polyimide film.After our work,the tensile strength have been greatly improved.