Chain conformation change upon heating for pauci‐chain polystyrene microsphere made by microemulsion polymerization

The conformation change of pauci‐chain polystyrene microsphere (micro‐PS) upon heating was investigated by in‐situ FTIR. For the peaks at 1492 and 1452 cm⁻¹ due to phenyl ring semicircle stretch, there are two discontinuities in the plots of peak height versus temperature. The first discontinuity at around 100 °C corresponds to the glass transition. The second discontinuity at about 155 °C is in good agreement with the second exotherm in the first DSC scan, which clearly suggests a non‐negligible change of the chain conformation at this temperature. This finding may be of help in further illustrating the two exotherms of micro‐PS in its first DSC scan.