Origin of embrittlement in Polyamide 6 induced by chemical degradations: mechanisms and governing factors

Polyamide 6 films were aged in two environments inducing either only oxidation or hydrolysis of the polymer for up to years. Ageing temperatures ranged from 80°C 140°C. Samples characterized periodically terms both chemical structure at macromolecular scale, using SEC, DSC, SASX and WAXS, mechanical behaviour through tensile tests. Both degradation mechanisms lead chain scission within polymer, an increase crystallinity ratio, a decrease amorphous layer thickness embrittlement polymer. First strain break is observed while maximal stress remains unchanged. Then drop identified. Using these experimental results, origin factors governing are discussed. The attributed first time polyamide concentration tie molecules determined theoretical approach. loss entanglements associated with stress. Furthermore, it shown that ratio does not govern polyamide. However, molar mass faithful indicators this whatever mechanism.