The synthesis of some series of oligo(oxytetramethy1ene oxyterephthaloyl) [oligo(butylene terephthalate)~] with different but well-defined end groups is described. The separation of artificial mixtures of the oligomers by high pressure liquid chromatography was studied under various elution and column conditions, and thus, the purity of the individual oligomers was demonstrated. The equilibrium melting point T z = 236 k 4°C and the corresponding heat of melting AH: = 28,7 kJ.mol-' of poly@utylene terephthalate) was determined from the analysis of the melting behaviour of the oligomers as depending on the degree of polymerization and the structure of the end groups. P E. oxyterephthaloyl) (44) 2 (3-n) x o-benzyloxyoligo(oxytetramethy1en-6, 8, 10 a-Hydro-o-benzyloxyoligo(oxytetra-Benzyl-butan-BzfT-B jnH 1 , 2 , 3,4 H t Omethylenoxyterephthaloyl) (5-n) diolester -OCH,C,H, 9 m a-(4-Carboxybenzoyl)-o-hydroxy-Dicarbonsiuren HOfT-B+T-OH 0, 1, 2, 3, 4, 6 -OH oligo(oxytetramethy1enoxyterephthaloyl) ( 6 4 a-Hydro-w-tert-butoxyoligo(oxytetra-t-Butyl-butan-tB+T-B+H 192, 3 H t Omethylenoxyterephthaloyl) ( 7 4 diolester a-(2-Tetrahydropyranyl)-o-[4-(tetra-THP-Esterdiole THPtB-T+B-THP 1, 2, 3 hydropyran-2-yloxy)butoxy]oligo-(oxytetramethylenoxyterephthaloyl) ( 8 4 5 9 W W 0 W
The mutual compatibility of oligo(tetramethy1ene terephtha1ate)s l a ~ d and their compatibility with oligoethers 2, 3, and 4 and block copoly(ether ester)s 5ac based on poly(tetramethylene terephthalate) and poly(oxytetramethy1ene) is reported. From the binary phase diagrams of the oligoesters it is concluded that the oligoesters d o not cocrystallize and the melt of the lower melting compound is not a good solvent for the higher melting homologue. For the trimer/pentamer (lb/lc)-blend the eutectic composition contains 3 mole-% of the pentamer l c . Oligo(oxytetramethy1ene) (3) is a better solvent for the oligoesters than oligo(oxyethy1ene) (2). The addition of an oligoester to the block copoly(ether ester) induces a change in the phase behaviour of the polymer, resulting in a melting point of the blend higher than for the pure polymer or oligomer.
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