Hot‐embossing experiments of polymethyl methacrylate across the glass transition temperature with variation in temperature and hold times

Hot‐embossing (HE) experiments were conducted on polymethyl methacrylate (PMMA) across its glass transition temperature from 92 to 142°C. The glass transition temperature ( T g ) of the PMMA used in this study was ∼ 102°C. The polymer samples were embossed to a depth of 0.8 mm (800 μm). The experiments were carried out at various temperatures for different hold times of 30, 90, and 180 sec during the embossing process. A few additional experiments were conducted at 142°C with cooling of the samples as well. The force required for embossing and the final depth of the embossed features were analyzed. Polymers, including PMMA, show significantly different material behavior around and above T g . The same was seen in the aforementioned tests; the trends observed for the force as well as the final depth changed considerably around 122°C ( T g + 20). These findings will be used in developing material models for use in simulating the hot‐embossing process. POLYM. ENG. SCI., 2012.