| 초록 |
The order-order transition temperature (TOOT) in two mixtures of styrene-isoprene diblock copolymer (Mw=3.5x103 and styrene wt%=30.0)/polystyrene homopolymer (HPS) and isoprene-styrene-isoprene triblock copolymer (Mw=1.4x104 and styrene wt%=18.3)/HPS was investigated by using small-angle X-ray scattering (SAXS) and DSC measurements. It was found that the TOOT of the mixtures depends on the molecular weight of HPS added to the mixtures. As the molecular weight of added HPS increased, the TOOT of mixtures increased. This phenomena could be explained by the variation of product χN, the quantity that controls the degree of segregation between the two blocks. The addition of high molecular weight HPS increases the degree of segregation. On the other hand, the low molecular weight HPS added to block copolymer tends to disorder a microstructure and also have a reduction effect on the mean molecular weight of block copolymer. Thus, the addition of low molecular weight HPS decreases the segregation temperature. Hence, the OOT of the mixtures having low molecular weight homopolymer occurs at a lower temperature. |
