Melt-crystallized segmented aromatic-aliphatic copoly(ester-ester)s based on poly (butylene terephthalate)
and a dimerized fatty acid
Polimery 1997, No 1, 35
Variations in the supramolecular structure of the title copoly(ester-ester)s were followed by DSC, transmission electron microscopy (ТЕМ) and optical polarizing microscopy (OM) as a function of the proportions of thepoly(butylene terephthalate) (PBT) hard and the dimerized fatty acid (DFA) soft segments. The temperatures of copolymer's glass transition (Tg) and of meltingand crystallization of the hard segments and also the enthalpy of melting and degree of crystallinity rose as the PBT content was raised. The Tg varied asthe noncrystalline and compatible PBT content in the amorphous phase rose. Segment compatibility controlled the amounts and size of the crystallizing spherulites and dendrimers, the former growing smaller as the soft segments were raised in proportion. The (1:1 w/w) PBT-DFA copolymer (C) was the only one to form the dendrimeric suprastructure. Separated from the amorphous branched DFA and noncrystalline PBT, the lamellae due to crystalline PBT, 20 mm thick in each specimen (A, В and C), grew thicker upon thermal treatment. Microphase separation was apparent from the ТЕМ evidence.
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