Polymers at High Pressures and High Temperatures: Advances in Equation of State and Phase Transition Investigations

Polymers are one of the most widely used materials in modern society. The interest of applying polymers under extreme conditions (high pressure and high temperature) is ever increasing. However, our knowledge of the equation of state (EOS) and phase transition of polymers at high pressures and high temperatures is extremely limited, which prevents their applications in broad fields. Because of their mixed phases and their hierarchical structures, investigation on the structures and properties of polymers at extreme conditions is a big challenge to date. In this short review, we summarize the recently published studies on the EOS and phase transition of polymers at extreme conditions. We point out the challenges faced and the limitations of the experimental techniques used, which is expected to be useful for the investigations of the EOS and phase transition of polymers in the future.