Remediação do processo de embranquecimento de peças injetadas de poli (propileno-co-etileno)

TL;DRAbstract

In this work we studied an alternative to minimize degradation and whitening of injected parts made of TiO 2 containing poly(propylene-co-ethylene). The catalytic effect of the white pigment TiO 2 (anatase and rutile) in the polymer photooxidation has been assigned to the reaction of an excited electron in the conduction band of TiO 2 with atmospheric O 2 . For long periods of ambient exposition it was observed that tension generated by flexion does not affect degradation, and it was assigned to polymeric chain relaxation processes. To minimize catalytic action of TiO 2 we used the black pigment conducting carbon black (CCB) in substitution to the non conducting grade (CB), and it has been verified less degradation in these samples. The effect was not observed for samples without TiO 2 , hence the process is related to the interaction between CCB and TiO 2 . We propose that the improvement of stability is associated to deactivation of the excited electron in the conduction band of TiO

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