| abstract |
A composition that softens at a predetermined temperature between about 20oC and about 62oC, comprising at least one block copolymer having at least two thermal transition temperatures. The composition is characterized by at least two thermal transition temperatures, one of which is a predetermined lower transition temperature between about 20oC to about 62oC and one of which is an upper transition temperature above about 62oC. The composition has the physical properties of a rigid, crystalline or glassy polymer below the predetermined transition temperature and the physical properties of a flexible, rubbery polymer at and above the predetermined transition temperature, but below the upper transiiton temperature. In a preferred embodiment, the composition of the present invention further comprises a plasticizer or polymer that has at least one thermal transition temperature and is thermodynamically compatible with at least one block of the block copolymer. For most biomedical applications, the composition of the present invention has a predetermined glass transition temperature at or near body temperature. The present invention also provides a method of making the composition, a method of making biomedical devices and materials and articles with shape-memory properties from the composition, and biomedical devices and materials and articles with shape-memory properties made from the composition. |