In this study, property changes of controlled aged LDPE/feather composites in comparison to those of nonaged samples were investigated by mechanical tests, dynamic rheological and thermal tests, infrared spectroscopy, and oxygen permeability analysis. The viscoelastic behavior of the aged composites was modified, whereas a pseudoplastic character was observed for the nonaged samples. After weathering, infrared spectroscopy indicated the formation of carbonyl and vinyl groups, and the oxygen permeability became significantly higher than for the reference samples. DSC results showed α-helix denaturation of keratin after aging and an increase in crystallinity due to reinforcement of composites containing feather fibers upon UV exposure. An aging time of 500 h was found to induce surface degradation of composites, especially for a feather fiber loading of 10 wt %.

Dielectric properties of breast tissue obtained from 131 patients were investigated by an open-ended probe separated from the tissue by a dielectric film (plastic foil). The film decreases the measured capacitance, but the content of blood and body liquids has little effect on the measured quantity. We found that in cancerous tissue the electric capacity (related to the permittivity) measured at f > or = 10 MHz using the modified probe is higher than that in normal tissue. The dielectric assignment was confirmed by histopathology in 94% of investigated cases. High efficiency in differentiation between normal and cancer breast tissues and the feasibility of fulfilling of aseptic conditions (a film covering the probe) are promising in intra-operative cancer diagnostics.

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For the investigation of the differences between cancer and normal breast tissue we propose an open-ended probe with additional non-conducting foil. The modification changes the dielectric response considerably, but the differences between normal and cancer tissue are still detectable. The method was found not to be sensitive to the existence of blood and electrolytes. We found that in 98% of the investigated cases the dielectric assignment is consistent with the histopathological one. The high efficiency in differentiation between normal and malignant tissue is promising in cancer diagnostics.