Premium
Low Temperature Endotherm in Multiblock Terpoly(ester‐ b ‐ether‐ b ‐amide) Thermoplastic Elastomers
Author(s) -
Ukielski Ryszard
Publication year - 2001
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/1439-2054(20010601)286:6<337::aid-mame337>3.0.co;2-9
Subject(s) - endotherm , elastomer , materials science , thermoplastic elastomer , amorphous solid , glass transition , polymer , solubility , polymer chemistry , composite material , copolymer , differential scanning calorimetry , thermodynamics , organic chemistry , chemistry , physics
The phenomenon of the occurrence of a middle‐temperature thermal effect in crystallizable multiblock thermoplastic elastomers, the so‐called annealing endotherm has not yet been univocally explained, hence, it was subjected to DSC analysis. The formation of this endotherm in response to the time and temperature of conditioning (stabilisation) of the sample has been followed. The investigations have been performed for a specific polymer system, poly(tetramethylene terephthalate)‐ block ‐poly(oxytetramethylene)‐ block ‐polylaurolactam‐(PBT‐ b ‐PTMO‐ b ‐PA12)‐ n . The specific property of this elastomer is the solubility or a partial solubility of one of the components (PBT block) in the two remaining ones being mutually insoluble. The occurrence of the two different amorphous phases (PBT and PA12) in this elastomer with glass transition temperatures T g > 20°C is also possible. This specific system permits to observe an interesting phenomenon, since at the points determining the middle‐temperatures of the glass transition temperatures of the elastomer, the two small endotherms are shaping; after proper stabilisation they are approaching each other, and as a result of this process they would form one extreme. This extreme comprises the thermal effect of the dispersion of the mesomorphic aggregates being the intermediate form between the amorphous state and the crystalline state. The mesomorphic aggregates constitute the additional network points of the physical polymer network of the elastomer.