| 초록 |
The glass transition temperatures of soft and hard segments of segmented polyurethanes are of practical significance for both tailored molecular design and interpretation of the extent of phase mixing between the soft segment and hard segment, yet the data are sparse in the open literature. Various types and lengths of hard segment and soft segment of polyurethane were respectively synthesized and characterized by using FT-IR, GPC, and DSC. The results showed that the glass transition temperature of hard segment and soft segment asymptotically increased with increasing molecular weight of the segment, regardless of the type and length of polyol and type of isocyanate as well. To quantitatively analyze the data, Fox-Flory type relationship was employed and the two parameters (A and B) were determined using a least square method. Consequently, this enabled one to predict the glass transition temperature as a function of molecular weight. |
