Wpływ częstotliwości obciążeń zmęczeniowych na właściwości mechaniczne, barwę i połysk wyprasek wtryskowych z poliamidu 6.10

The examinations of changes in mechanical properties, colour and gloss of injection molded parts from polyamide PA 6.10 after cyclic loading with varying frequency, at a constant level of deformation, are presented in the article. The relationships between the stress and the elongation of samples after 1 and 3000 cycles of tensile - compression tests were registered and the hysteresis loops were obtained. It was found that cyclic loading causes changes in mechanical properties of samples. In investigations of the effect of loading frequency on hysteresis loop shape it was stated that the value of the maximum stress increased with the increasing load frequency. In the DSC examinations, the effect of loading frequency on the degree of crystallinity of samples, and changes in the range of the melting point of the crystalline phase of polyamide were shown. Small changes in the degree of crystallinity in the surface layer and the core of samples during cyclic loading with different frequencies were observed, but generally the degree of crystallinity in the surface layer is higher than in the core. Cyclic loading affects also the colour and gloss of samples. Smaller changes in colour of loaded samples occurred at the lower value of cyclic loading frequency. The gloss of samples after cyclic loading is lower than not loaded ones and with the increase in loading frequency the gloss decreases.