HDPE are usually uncross-linked polymer. It has glassy transition temperature typically below -100 oC. Why does HDPE behave like a strong solid with reasonable stiffness at room temperature? What prevents HDPE flowing at room temperature? If we want to recycle HDPE products, what temperature does we need to heat up to and why? • PS has a glass transition temperature around 100 oC. Why does PS have a significantly higher glass transition temperature than PE? • Please combine thermodynamics and molecular structure to explain why Nylon has a high melting temperature? • The diagram is the DSC curve of PLLA and PLGA physical blends with different weight ratio of two polymers (e.g., 25/75 means the blend contains 25 % PLLA and 75% PLGA). Can you tell if PLLA and PGA is miscible or not and why?
