Influence of molecular weight and composition on the morphology and mechanical properties of SBS-polystyrene-mineral oil blends

Abstract

The relationship between the tensile properties and morphology of styrene-butadiene-styrene (SBS)-mineral oil-polystyrene blends has been evaluated. The SBS-mineral oil system (Kraton D2104,21 wt % total styrene content, Shell Chemical Co.) exhibits a morphology of polystyrene spheres in a continuous butadieneoil matrix, and the mechanical properties are characteristic of a cross-linked rubber. When the mineral oil is removed, the polystyrene domains become cylindrical and the mechanical properties correspondingly show increased stresses and a reduced ultimate elongation. Monodisperse polystyrene was blended into the SBS-mineral oil system: mineral oil is solubilized exclusively into the butadiene phase of the copolymer and the SBS-mineral oil-homopolymer blends seem to behave similarly to SBS-homopolymer blends. As the total styrene content is increased through blending, a transition from a spherical to cylindrical styrene domain morphology is observed. Higher styrene content blends also exhibited yielding and necking, which are indications of polystyrene domain continuity. The solubility limit of the homopolystyrene in the copolymer morphology was dependent on homopolymer molecular weight. Only the lowest molecular weight polystyrene blend showed no evidence of homopolymer segregation at the highest total styrene content (40 wt % 1. For polystyrene molecular weights greater than the styrene block length of the copolymer, the solubility limit was significantly reduced. The dependence of mechanical properties on homopolymer molecular weight and morphology is more sensitive than has previously been observed.

Thermoplastic elastomer gels. I. Effects of composition and processing on morphology and gel behavior

“…Previous studies [23][24][25][26] of SEBS copolymer/oil blends have shown that the oil is completely bound within the midblock network at oil mass fractions (w oil ) of up to 0.90. Polizzi et al 27 also find this to be true for solvated poly(styrene-bbutadiene-b-styrene) (SBS) triblock copolymers.…”

The Potential Use of Epoxy‐POSS as a Reactive Hybrid Compatibilizers for PLA/PBAT Blends: “Effect of PBAT Molecular Weight and POSS Type”

“…As a result, nonspherical but snowman‐like particles with Janus morphology were formed . In another study, it was shown that the morphology of styrene–butadiene–styrene‐mineral oil–polystyrene blends was influenced by the molecular wiight of polystyrene . The other properties of the polymer blends such as tensile, impact, thermal, and so forth are also influenced by the molecular weight differences of the components.…”

Influence of Hydrocarbon Oils on the Physical Gelation of Poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) Triblock Copolymers

“…These polymers have the glass transition temperature (T g ) of their rubber block below À50 C, retaining their rubbery properties at low temperatures. Numerous significant researches have been carried out for understanding the structural morphologies [9][10][11][12][13][14][15][16] and viscoelastic and thermal properties [17][18][19][20][21][22][23] of these systems in extender oils and n-octane. The results showed that gels exhibited a pronounced superstructure and rheological properties, which functions are of block copolymer concentration, molar mass, end/block ratio, deformation, and temperature.…”