Resumo

HERRERA-NAJERA, R.; GARCIA-GUZMAN, G.; XICOTENCALT-SERRANO, H.  e  MEDINA-TORRES, L.. On the effect of the composition of the elastomeric block of SBS and SEBES block polymers on the rheological properties of modified aphalts. Rev. Mex. Ing. Quím [online]. 2012, vol.11, n.1, pp.133-144. ISSN 1665-2738.

The behaviour of asphalt (PMA) modified with SBS (lot 416) and SBEBS was studied to elucidate the effect of the composition of the elastomeric block of these two types of polymers on the morphology and rheology of PMAs. The SBEBS polymers were produced by homogeneous hydrogenation of the SBS having different degree of saturation of poly-butadiene double bonds (0%), 7%, 29% and 49%). Asphalt modified samples (PMA) with 10 wt % of polymer were prepared by hot mixing proces_j (180 °C, 4 hours, 5000 rpm). Fluorescence microscopic analysis indicated that PMA are heterogeneous materials exhibiting a polymer-rich and asphalts-rich phases. Oscillatory flow rheology analysis for various temperatures (40-90ºC) indicate that all PMA prepared with SBEBS with higher saturation degree undergo structural c h angei exhibiting a higher viscoelastic response, and higher elasticity (G'>G"). The Maxwell multimodal model was employed to reproduce G' and G" master curves. It was observed thai the number of relaxation modes required to fit the data of SBEBS modified asphalt increases with the degree of polybutadiene saturation, since 12 modes are need are for SBEBS with 49 % of saturation while 8 modes are enough to fit the data of SBEBS 7 % of saturation.

Palavras-chave : asphalt; poly (styrene-block-butadiene-block-styrene-block) (SBS), poly (styrene-block (butadiene)_1-x-(ethylene-co-butylene)_x -block-styrene-block) (SBEBS); viscoelastic materials; Maxwell multimodal model.

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