| Abstract
| - The phase behavior of the (EO)19(PO)43(EO)19/p-xylene system (where EO is ethylene oxideand PO is propylene oxide) with temperature is discussed. In this block copolymer the end blocks arecrystallizable, and the middle block is noncrystallizable. Several techniques were used to delineate thephase boundaries (SAXS, WAXS, 1H NMR, 2H NMR, and DSC). An anisotropic region with a lamellarstructure with semicrystalline PEO domains and amorphous PPO domains is formed at low temperaturesand high copolymer concentrations. The lamellar structure has a one-dimensional swelling with increasingp-xylene concentration. The driving force for forming the anisotropic region is that the PEO crystallizeat low temperatures. The amount of crystallinity in the system and the interfacial area per PEO blockin the ordered region depend on the temperature and the sample composition. At high temperatures andlow copolymer concentrations the system contains an isotopic solution phase.
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