Preparation of isocyanate functionalized styrene-ethylene-butadiene-styrene copolymer and its blending with polyamide 6

Styrene-ethylene-butadiene-styrene copolymer (SEBS) was radically functionalized with 3-isopropenyl-alpha, alpha-dimethylbenzyl isocyanate (TMI) in solution. FTIR analysis confirmed the formation of SEBS-g-TMI. The peak at 2 256 cm -1, characteristic of -NCO groups in SEBS-g-TMI, revealed the evidence of grafting occurrence. Due to the intensive interaction between -NCO groups, the apparent viscosity of SEBS-g-TMI is much higher than that of SEBS and increased with increasing the grafting degree of TMI. The apparent viscosity of SEBS-g-TMI is approximately increased by two orders of magnitude, compared with that of SEBS under the same shear stress. Comparison with the blends obtained from ungrafted SEBS and PA6 shows that impact strength of SEBS-g-TMI/PA6 is dramatically enhanced, which is strongly dependent upon the grafting degree of TMI, indicating that isocyanate functionalized SEBS can act as potential compatibilizer for PA6.