Thermoplastic elastomers DMTA

The thermal transitions and the relaxation processes observed in multiblock terpolymers allow to evaluate their phase morphology. At room temperature, these polymers are composed of three phases hard, soft, and strongly expanded interphase. The two latter phases are amorphous and form a matrix (continuous phase), whereas the hard (crystalline) phase is the dispersed phase. The thermal transition and relaxation processes occurring in the interphase of the multiblock copolymers are not detected by the DSC and DMTA methods. The incorporation of the third short block into the copolymer chain causes an increase in the volume of the interphase. This facilitates the establishment of the processes occurring in this phase at various temperatures. Moreover, it enables the evaluation of the influence of the dimension and composition of this phase on the polymer properties. (About the number of phases in poly(ether ester) thermoplastic elastomers, see also Chapter 6.)... 

Strain-induced two-stage polymorphic transition in blends of PBT and PEE as revealed by microhardness measurements in real time. The results of the polymorphic transition obtained in real time on a blend of PBT and a PEE thermoplastic elastomer, the latter being a copolymer of PBT and PEG, are considered here. It should be mentioned that these blends are well characterized by DSC, SAXS, DMTA, and static mechanical measurements [28,78-81]. 

The structure and physical properties of the thermoplastic vulcanizates (TPE-V) produced in the process of the reactive processing of pol5rpropyl-ene (PP) and ethylene-octene elastomer (EOE) in the form of alloy, using the cross-linking system was analyzed. With the DMTA, SEM and DSC it has been demonstrated that the d5mamically produced vulcanizates constitute a typical dispersoid, where semicrystal PP produces a continuous phase, and the dispersed phase consists of molecules of the cross-linked ethylene-octene elastomer, which play a role of a modifier of the properties and a stabilizer of the two-phase structure. It has been found that the mechanical as well as the thermal properties depend on the content of the elastomer in the blends, exposed to mechanical strain and temperature. The best results have been achieved for grafted/cross-linked blends with the contents of iPP/EOE-55/45%. 

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