ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Mechanical Properties of Polyamide Modified by Block Copolymers: Possible Effect of Tie-Molecules

M. Kučera, L. Vojtová, and J. Kotas

Institute of Materials Chemistry, Faculty of Chemistry, Technical University, CZ-637 00 Brno

Abstract: Appropriate block ABA copolymers can be suitable agents capable of increasing the number of tie-molecules in the polyamide (PA) blend.In this work, macromonomers of PA (block A), with backbone chains endcapped with -NH₂ group on one end, and of polyethyleneterephthalate (PET) (block B), with -COOH groups on both ends, have been used. The -COOH and -NH₂ end groups of these macromonomers were reacted via condensation reaction joining the A and B blocks to form the desired triblock copolymer PA-PET-PA. Reactions proceeded in a melt in a single screw extruder.The ABA copolymer was added in different amounts to the PA's matrix. The outside blocks of that copolymer conformed with the polymer matrix and the inner block did not co-crystallize with it. The stress-strain behaviour (yield stress, stress at break, yield strain, elongation at break, and notched impact strength) of these polymer blends was studied as a function of the mole fraction of the inner block. All mechanical characteristics were improved. It is suggested that the improvement can be attributed to the higher amount of tie-molecules in the modified polymeric material.

Full paper in Portable Document Format: 504a233.pdf

Chemical Papers 50 (4) 233–237 (1996)