Notch effect saturation

Polyamides and saturated polyesters can be toughened with ABS, ethylene-propylene copolymers/terpolymers or EPDM rubbers grafted with maleic anhydride to increase the dispersion and adhesion of the modifier. Styrene-butadiene copolymers are also effective. The notched Izod impact strength of polyamide 6-6 can be increased more than 20-fold by impact modifiers, whereas short glass fibres often reduce the impact strength, even though they increase the modulus. 

This is demonstrated by the results of notch Impact tests (Pig. 1) in which the transition temperature is increased by both hydrogen and irradiation, although the latter effect appears to saturate at a dose between 10 9 and 1020 n/cm2 (>i MeV),... 

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