Styrene−Butadiene−Styrene Triblock Copolymers Modified with Polyhedral Oligomeric Silsesquioxanes

Abstract

A novel hybrid organic/inorganic triblock copolymer of polystyrene-butadiene-polystyrene (SBS) containing grafted polyhedral oligomeric silsesquioxane (POSS) molecules was synthesized by a hydrosilation method. The POSS molecules were designed to contain a single silane functional group, which was used to graft onto the dangling 1,2-butadienes in the polybutadiene soft block. Unlike typical free radical copolymerizations commonly used for many other POSS incorporations investigated, this synthesis method allows us to make a series of polymers with varying amounts of POSS without any change to the overall degree of polymerization or structure of the main SBS backbone. This gives us a unique opportunity to study the POSS behavior in the matrix and know that all differences are solely due to the POSS grafted to the soft continuous butadiene phase. X-ray diffraction revealed that the grafted POSS are very well dispersed in the matrix of the hybrid polymer, which is compared to the strong phase segregation observed in a POSS physical blend. Small-angle X-ray scattering indicates that although the cylindrical morphology attributed to the styrene component was not altered by the presence of POSS, attachment of POSS to the continuous phase (polybutadiene block) causes the packing of discrete phase (polystyrene blocks) to lack long-range features. Results of dynamic mechanical analysis showed that the POSS has sterically hindered the motion of the polybutadiene blocks. More interestingly, the presence of POSS in the soft segments also resulted in a tapered tan δ peak associated with the glass transition of polystyrene and a higher tensile strength when deformed at temperature near T g of polystyrene without affecting the elongational behavior of SBS at temperatures above Tg of polybutadiene.

Novel elastomer dye-functionalised POSS nanocomposites: Enhanced colourimetric, thermomechanical and thermal properties

“…This can lead to further complications when the objective is to disperse fillers within a particular phase. The incorporation of POSS into SBS has been limited [16][17][18]. Furthermore, SBS-POSS nanocomposites are usually prepared with grafting reactions.…”

Synthesis of grafted polysilsesquioxane by ring-opening polymerization of lactide and trimethylene carbonate

“…Consequently, various combinations of polymeric components and PSQs have been investigated. [8][9][10][11][12] We have previously investigated the grafting of the biodegradable polymers e-caprolactone (CL) and L-(-)-lactide (LA) from the PSQ main chain containing phenyl and aminopropyl groups (APSQ). 13,14 In thermal analyses of the resultant PSQs, low crystallinity of the polymeric components seems to be induced by the presence of the polysiloxane structure.…”

Synthesis of thermoresponsive polysilsesquioxane with methoxyethylamide group and crown ether

“…Graft polymerizations onto and from the PSQ main chain are one of the most effective methods of making modifications, in which the polymeric component provides an additional property besides durability for heat and weatherability based on the inorganic polysiloxane backbone. [12][13][14][15][16] Among the various functions conferred on the hybrids on the basis of their polysiloxane structure, thermoresponsive phase separation in an aqueous solution is one of the useful properties. This property is required of materials used for microencapsulation, biosensors, drug delivery and so forth, as reported in a variety of recent works.…”