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See detailDifunctional initiator based on 1,3-diisopropenylbenzene. 7. Mechanical and thermal properties of new butadiene-based thermoplastic elastomers
Yu, Y. S.; Dubois, Philippe ULg; Jérôme, Robert ULg et al

in Rubber Chemistry and Technology (1997, November), 70(5), 820-838

Mechanical and thermal properties of SBS thermoplastic elastomers, in which S stands for polystyrene and B for polybutadiene, can be remarkably improved through end-capping by syndiotactic poly(methyl ... [more ▼]

Mechanical and thermal properties of SBS thermoplastic elastomers, in which S stands for polystyrene and B for polybutadiene, can be remarkably improved through end-capping by syndiotactic poly(methyl methacrylate) sequences. Furthermore, the upper service temperature of these sPMMA teleblock copolymers can also be enhanced by blending with isotactic PMMA so that the rubbery PBD soft segments are connected to high-melting stereocomplexed hard segments. The factors which affect the mechanical and thermal properties of these novel thermoplastic elastomers have been extensively investigated. [less ▲]

Detailed reference viewed: 34 (4 ULg)
See detailNew polybutadiene-based thermoplastic elastomers: synthesis, morphology and mechanical properties
Dubois, Philippe ULg; Yu, Y. S.; Teyssié, Philippe et al

in Rubber Chemistry and Technology (1997, November), 70(5), 714-726

Well defined poly[styrene-b-butadiene-b-styrene] block copolymers (SBS) end-capped with poly(t-butyl methacrylate) (PtBMA) and poly(methacrylic acid) (PMA) outer blocks, respectively, have been ... [more ▼]

Well defined poly[styrene-b-butadiene-b-styrene] block copolymers (SBS) end-capped with poly(t-butyl methacrylate) (PtBMA) and poly(methacrylic acid) (PMA) outer blocks, respectively, have been synthesized by the sequential anionic polymerization of butadiene, styrene and tBMA, followed by the selective hydrolysis of the PtBMA blocks into the corresponding PMA blocks. The structure-property relationships of these new thermoplastic elastomers have been investigated, with a special emphasis on the effect of the ester or acid outer blocks on the bulk properties. As a rule, tensile strength is improved by increasing the length of the ester or acid outer blocks from 0 to 140 methacrylic units. Dipole-dipole intermolecular interaction of the PtBMA blocks and hydrogen bonding of the PMA blocks may account for enhanced mechanical properties. However, too high a degree of strong intermolecular interactions can constitute a deterrent to good phase separation. This is supported by morphological observations and loss in tensile properties when the relative content of the ester or acid outer blocks exceeds some critical value. In the case of a high acid content, DSC analysis shows two thermal transitions at -70 ??C and 230 ??C for PBD and PMA blocks, respectively. [less ▲]

Detailed reference viewed: 49 (7 ULg)