A study on the toughening of polyamide-6 (PA-6) with a new elastomeric modifier, brominated poly(isobutylene-co-p-methylstyrene) (BrXP-50), was conducted. Morphological analyses and mechanical tests were combined to evaluate the toughening mechanisms of modified PA-6 and the fracture mechanism of unmodified PA-6. We conclude that the fracture mechanism of unmodified PA-6 in the impact test is crazing-cracking under the dilatational stress created by the plastic constraint, while that of the BrXP-50 elastomer modified PA-6 is plastic tearing limited by the ultimate tensile strain. Cavitation of BrXP-50 elastomer particles occurred in the impact test, and is proposed as a controlling step in toughening: it relieves the plastic constraint so that the cracking process is postponed and additional plastic deformation can occur, leading to higher impact toughness.
Посилання на статтю:
The toughening of polyamide-6 by brominated poly(isobutylene-co-pmethylstyrene): fracture and toughening mechanisms / Dongming Li and A. F. Yee and K. W. Powers, H.-C. Wang* and T. C. Yu // Polymer. – 1993. – Vol 34. – P. 4471-4480.