Zmiany struktury poliamidu 6 w procesie niszczenia zmęczeniowego

The results of measurements of selected parameters which characterise the physical-structure of Polyamide 6 (Tarnamid T-27) before and after mechanical fatigue are presented. Assessed were the cross dimensions of crystallites the lenght of crystalline regions the mass- and volume-degree of crystallinity. In addition the perfection index of crystalline region according to Roldan's formula was determineted. Mechanical fatigue tests were carried out at sinusoidal cycle for cantilever beam with 15 Hz frequency. During the fatigue process alt measured structural parameters can alt alter. From these only the length of crystallites increases to m maximum 10% – the other structural parameters decrease in the
range from 8 to 25%. The width of the crystallite is the quantity which is independent of the amplitude of stress and
of the number of cycles till fracture N. This effect may be a basis for investigating of such thermal-mechanical process which generates the growth of the crystallite width during a constrained crystallisation or recrystallisation of Polyamide 6.