Data from the FTIR spectra of both the SBS and resultant SBEBS polymers were used together with Eq.
tr] of the SBEBS copolymers, as calculated from the FTIR spectra.
Samples of SBS and SBEBS were analyzed by GPC to determine the effect of the hydrogenation process on the molecular weight of the polymer; potential changes in the hydrodynamic volume of the SBS to the SBEBS were not considered.
3-10 Li/Ti; rows 8-10), a lower saturation of the polybutadiene block and a decrease in the molecular weight of SBEBS were found in comparison to its precursor SBS.
Furthermore, the decrease in the molecular weight was attributed to the occurrence of undesirable chain scission reactions produced by excessive polymer hydrogenation , Our data in Table 3 (rows 8-10) indicate that SBEBS of a smaller molecular weight was produced when the composition of the system contained a relatively large amount of Ti (1.
Once the hydrogenation conditions were established that allowed the selective saturation of the polybutadiene block without saturation of the polystyrene block and without promoting changes in the molecular weight, a series of SBEBS copolymers with different degrees of saturation were prepared to investigate the effect of the degree of saturation of the polybutadiene block on the properties of the resulting SBEBS copolymers.
Samples of P-MA with 3 and 10 wt% of SBS or SBEBS were produced through high-temperature mixing process, using a stainless steel tank equipped with a thermal jacket and high shear rate stirrer (IKA, Yellow Line OST 20); nitrogen atmosphere blanket was used to minimize polymer degradation.
1 and 2 and Table 2, P-MAs with 3 wt% of either SBS or SBEBS (Fig.
Both SBS and SBEBS have a starlike molecular architecture with four equivalent diblock arms emanating from a silicon-based core with central elastomeric-b and free-ends polystyrene-b; thus, they are considered triblock as four polystyrene-h flank a central core of elastomeric-b.
To explain the fact that SBS-MAs and SBEBS-MA (with either 3 wt% or 10 wt% of polymer) exhibited somehow similar morphology yet the AP-PRP of SBS-MA was smaller than that of the corresponding SBEBS-MA (Table 2), it was considered that both SBS and SBEBS were able to interact with the asphalt components allowing the formation of a biphasic morphological structure with a polymer-rich phase and an asphalt-rich phase coexisting in metastable equilibrium, although these two types of polymers have different solubility and compatibility with asphalt.
Therefore, the location of the G'([omega]) and [delta]([omega]) profiles (in the planes G'-[omega] and [delta]-[omega], respectively) and the slope changes of [delta]([omega]) were used for establishing the capacity of the SBS and SBEBS for asphalt modification.
However, the SBEBS-MA are more elastics and less responsive toward frequency changes because the dispersion of the SBEBS within the asphalt matrix is to some extent higher and the elastomeric-b of the SBEBS (poly[[(butadiene).