Influence of block molecular weight on the adhesion properties of segmented polyamides

The effects of molecular weight variations in the hard and soft segments on the adhesion strength of segmented polyamides against aluminium, copper, a nd steel were investigated using 180 degrees peel strength measurements. It was found that the adhesion strength of the segmented polyamides was large ly influenced by block molecular weight variations. The nature of the subst rate, the rate of peeling, cooling in different environments, and thermal a geing, etc. had significant effects on the adhesion strength of the joints, whereas variation in the moulding conditions used in these experiments did not have much impact on the strength of the joints. The joint strength inc reased with a decrease in hard block molecular weight at a constant soft bl ock molecular weight of 1000, or with an increase in soft block molecular w eight at a constant hard block molecular weight of 1100.