Franciszek Lembicz

Orientational processes in liquid-crystalline polymers due to a magnetic field as studied by electron paramagnetic resonance

Abstract A side-chain liquid-crystalline polymer has been investigated by the spin-probe method. It was found that the method detects a transition from the nematic to the isotropic phase, and that the rotational mobility of spin probes is connected with local mode processes of mesogenic groups. The phenomenon of domain orientation in an external magnetic field is also reported.

Selected dielectric and relaxation properties of PBT-DFA multiblock elastomers

The results of experimental investigations of poly(butylene terephthalate)-dimerized fatty acid (PBT-DFA) elastomers using dilatometric measurements, dielectric spectroscopy as well as ultrasonics are presented. Relaxation properties of the polymers are characterized in relation to the degree of crystallization of the hard segments. The variation of the polymer properties with temperature has been ascribed to two relaxation processes: glass transition (α-relaxation) and second order (β-transition) of the soft phase of elastomers.

Dynamics of soft segments phase in copoly(etherester) elastomers: a spin probe study

Two oligodiols, poly(ethylene oxide)glycol and poly(propylene oxide)glycol, and synthesized copoly (etherester) elastomers having these oligodiols as soft segments were investigated by the spin probe method. It was found that the rotational mobility of the probes is connected with the local mode α+β and β-relaxations in these materials. Comparison of the results obtained with analogous data for poly(oxytetramethylene) and related elastomers have shown that the relaxation runs for all oligodiols are almost the same and no difference was found for elastomers.

New multiblock terpoly(ester-ether-amide) thermoplastic elastomers

A new block terpolymer of poly(tetramethylene terephthalate)-block-poly(oxytetramethylene)-block-polydodecanelactam with potential application as elastomers have been obtained by melt polycondensation of α,ω-dihydroxypoly(butylene terephthalate), α,ω-dihydroxypoly(oxytetramethylene) (Mn ≈ 1000) and α,ω-dicarboxyoligo(dodecanelactam) (Mn ≈ 2000). The synthesis and some physical and chemical properties of this block poly(ester-ether-amide) thermoplastic elastomer is presented. A variety of different methods was used to study the phase structure, thermal and relaxational properties. Durch Schmelzcopolykondensation von α,ω-Dihydroxypoly(butylenterephthalat), α,ω-Dihydroxypoly(oxytetramethylen) (Mn ≈ 1000) und α,ω-Dicarboxyoligo(dodecanlactam) (Mn ≈ 2000) wurde ein neues Blockterpolymeres Poly(tetramethylenterephthalat)-block-Poly(oxytetramethylen)-block-Polydodecanlactam fur die Anwendung als Elastomeres erhalten. Die Synthese und einige physikalische und chemische Eigenschaften dieses Poly(ester-ether-amid)s werden vorgestellt. Phasenstruktur, thermische und Relaxationseigenschaften wurden mit verschiedenen Methoden untersucht.

Ultrasonic characterization of thermoplastic multiblock elastomers

Abstract The propagation of ultrasound waves in thermoplastic multiblock elastomers was investigated by measurements of the ultrasound velocity and attenuation. Three polymer series with amorphous-crystalline structure were studied. The soft-segment material was composed of three different oligomers for the three series: poly(1,4-oxypropylene)diol for series A, oligo(oxyethylene)diol for series B, and dimerized fatty acid for series C. The hard-segment material was composed of poly(butylene terephthalate) (PBT). The ultrasound velocity and attenuation of these elastomers with variable hard-segment concentration were investigated as a function of the temperature. The observed relaxation processes were ascribed to the glass transition of the soft phase. The possibility of a general description of these systems is discussed.