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Polymer/ceramic nanocomposites designed for application as electronic packaging were prepared using corotating twin‐screw extruder. The dielectric properties of the composites made from polyethylene terephthalate (PET), polyphenylene sulfide, and barium titanate were studied as a function of BaTiO3 fraction in the range between 0.75 and 1.5 wt%. Processing parameters were optimized in order to obtain the nanocomposites with appropriate dielectric properties like dielectric permittivity ε′, dielectric losses ε″, and their temperature stability in a wide frequency range. The measurements showed the increase of the dielectric permittivity value ε′ in the composites in comparison to both pure polymers. The dielectric loss factor tgδ of the composites was found to be much smaller than that of the pure PET. The weak influence of the ceramics on the temperature stability of the dielectric properties of the composites was stated. POLYM. ENG. SCI., 50:1613–1619, 2010. © 2010 Society of Plastics Engineers

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To be able to perform a two-dimensional study of free radical distribution by the continuous-wave electron paramagnetic resonance method in the X-band, special coils producing a magnetic gradient of 8 G/mm have been designed and construeted. The EPR spectra recorded for this gradient were subjected to the procedure of deconvolution in order to elieit information on the concentration of the radical distribution. The data obtained were used as the souree file of the program reconstructing the image. The reconstruction was based on the iterative simultaneous algebraic reeonstruction teehnique (Andersen A.H., Kak A.C.: Ultrason. lmag. 6, 81-94, 1984). The quality of the generated images depends on the angle of the sample axis to the gradient direction set by a goniometer and on the deconvolution procedures applied. The first tests on artificially generated phantoms indicated a dependence of the obtained images on the magnetic field gradients apptied. The determined spatial distribution of radicals has confirmed their uniform distribution in the sample. The preliminary tests were performed for diphenyl-picrylhydrazyl. Having proved the reliability of the method, analogous measurements were also performed for plyphenylene sulphide PPS-V1 and indicated a homogeneous distribution of radicals in the whole volume of the sample. The images obtained confirmed the uniforro distribution of the radicals.

NMR Studies of Molecular Motions in Phenylene SulfidesInternal motion in poly (p-phenylene sulfides) and in some low-molecular phenylene sulfides has been studied using NMR relaxation and broad line techniques. The relaxation rates T\~l in the laboratory frame at 30 or 15 MHz, and T^1 in the rotating frame at 45 kHz, and the second moments (or local fields or linewidths) have been measured over an extended range of temperatures for five different materials. For the polymers, the most important process has an activation energy of approximately 40 kJ/mole; it is ascribed to reorientational random oscillations of the phenylene groups, and it depends upon the detailed polymer structure. The origin of further processes of motion observed with activation energies of 20 and 11 kcal/mole is discussed. The rather narrow lines which occur in the NMR spectra at temperatures well above the glass transition are explained by the mobile fraction of chains of the non-crystalline regions.

The paper describes the process of the preparation of new nanocomposites based on poly(butylene terephthalate) and C60nanoparticles modified by decylamine (DA) and tetracyanoethylene oxide (TCNEO), respectively. Thermal and crystallization properties of new synthesized nanocomposites were investigated by means of thermal differential scanning calorimetry (DSC). The experimental results demonstrate the effect of fullerene derivates, DA-C60and TCNEO-C60, on the melting and crystallinity processes of nanocomposites. The morphology of new nanocomposites was investigated by SEM.

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