Application Note: Detecting Weak Glass Transition (Tg) in Polymers by HyperDSC
28 December 2015

Many polymers are semi-crystalline material. The percentage of crystallinity depends on many factors including chemical structure, interaction between polymer chains and processing conditions. When polymers get heated, the amorphous part will change from the glassy state to the rubbery state at the glass transition temperature (Tg). Since only the amorphous part contributes to the glass transition, for highly crystalline polymers, the glass transition (Tg) can be very weak. One typical example is High Density Polyethylene (HDPE), a highly crystalline engineering thermoplastic. It is typically used in applications demanding a material that is chemically inert, does not absorb moisture, can be utilized over a wide range of temperature, and exhibits a high tensile modulus. In this application note, an HDPE sample is used to demonstrate the increased sensitivity and ability to detect weak glass transitions with HyperDSC.