COPOLYESTERS CONTAINING POLYISOBUTYLENE SOFT SEGMENTS AND POLYBUTYLENE TEREPHTHALATE AS THE CRYSTALLINE SEGMENTS

The preparation and characterization of multiblock copolymers consisti ng of polyiso-butylene (PIB) soft segments connected to dimethyl terep hthalate (DMT) plus 1,4-butane diol (BD) hard segments (PIB-b-PBT)(n) are described. Syntheses involved solution poly-condensation of DMT BD + hydroxyl ditelechelic PIB (HO-PIB-OH). The overall block composit ion, and the lengths of the soft segments were varied in the M(n,PIB)= 1,400-10,000 g/mol range. The presence of PIE in the multiblocks was d emonstrated. The solubility in THF and other solvents, and extractabil ity of the polymers with n-hexane were studied. Efforts to determine s olution viscosity remained unsuccessful due to the insolubility of the polar and nonpolar segments in a common solvent. Mechanical testing g ave unacceptable results, however, the multiblocks showed good thermal stability (up to 367 degrees C in air) and melt processibility appear s to be feasible.