Hydrogenated block copolymers

The left panel is an example of a higher molecular weight version of a hydrogenated block copolymer with the same chemical structure as in the... 

Despite the body of patent literature describing fully hydrogenated block copolymers and their properties, it has been suggested that complete saturation of styrenic block copolymers with butadiene would result in materials that were incapable of microphase separation. This argument was based on the supposition that the difference in solubility parameters of the fully saturated block copolymer would be so slight that they would not have useful mechanical properties at achievable molecular weights [58]. This assumption has since... 

Linear low-density polyethylene (LLDPE) and PS resins were the same as described previously (Chapter 21). The various block copolymers that were used as compatibilizers have also been described (I). A series of crystalline copolymers (Q series) was prepared by hydrogenation of diblock and triblock copolymers of styrene and butadiene [styrene-hydrogenated butadiene (SEB) and styrene-hydrogenated butadiene—styrene (SEBS)J (1). Triblock copolymers of styrene and butadiene [styrene-butadiene-styrene (SBS)] and a noncrystalline hydrogenated block copolymer (SEBS) (Kraton) were supplied by Shell Chemical Co. Diblock copolymers of styrene and butadiene [styrene-butadiene (SB) (Vector)] were obtained from Dexco Polymers. The characteristics of the resins are given in Table I. 

S. Davidson and W. P. Gergen, Blends of Certain Hydrogenated Block Copolymers, U.S. Pat. 4,041,103. Thermoplastic IPNs of the block/crystal type. SEBS/polyamides. 

They provide an amphiphillic function in blends of dissimilar polymers, where favorable interactions exist between one of the homopolymers and one of the block copolymer segments.Hydrogenated block copolymers which reduce surface tension in polystyrene-polyoletin blends is one example. Another example is the use of a derivatized block copolymer, such as terminally carboxylated styrene-diene di-block copolymers,... 

Commercially, anionic polymerization is limited to three monomers styrene, butadiene, and isoprene [78-79-5], therefore only two useful A—B—A block copolymers, S—B—S and S—I—S, can be produced direcdy. In both cases, the elastomer segments contain double bonds which are reactive and limit the stabhity of the product. To improve stabhity, the polybutadiene mid-segment can be polymerized as a random mixture of two stmctural forms, the 1,4 and 1,2 isomers, by addition of an inert polar material to the polymerization solvent ethers and amines have been suggested for this purpose (46). Upon hydrogenation, these isomers give a copolymer of ethylene and butylene. 

The S—EB—S block copolymers produced in this way have excellent resistance to degradation (49). Similarly, S—I—S block copolymers can be hydrogenated to give the more stable S—EP—S equivalents. 

SBS and SIS can be subsequently hydrogenated to form SEBS and SEPS, respectively. SEBS is obtained from SBS with a higher vinyl content (typically around 30%) in order to avoid crystallization of the mid-block. The properties of all four of these common styrenic block copolymers are displayed in Table 2. 

S-B-S Triblocks are block copolymers consisting of a block of butadiene units flanked by blocks of styrene. Below the T, of polystyrene blocks from different chains congregate into domains which act both as cross-links and reinforcing fillers. The jDolymers will dissolve in hydrocarbon solvents. Hydrogenated S-B-S materials have better resistance to ageing. 

ADMET is quite possibly the most flexible transition-metal-catalyzed polymerization route known to date. With the introduction of new, functionality-tolerant robust catalysts, the primary limitation of this chemistry involves the synthesis and cost of the diene monomer that is used. ADMET gives the chemist a powerful tool for the synthesis of polymers not easily accessible via other means, and in this chapter, we designate the key elements of ADMET. We detail the synthetic techniques required to perform this reaction and discuss the wide range of properties observed from the variety of polymers that can be synthesized. For example, branched and functionalized polymers produced by this route provide excellent models (after quantitative hydrogenation) for the study of many large-volume commercial copolymers, and the synthesis of reactive carbosilane polymers provides a flexible route to solvent-resistant elastomers with variable properties. Telechelic oligomers can also be made which offer an excellent means for polymer modification or incorporation into block copolymers. All of these examples illustrate the versatility of ADMET. 

Saturated styrene-ethylene-butylene-styrene (SEBS) and styrene-ethyl-propyl-styrene (SEPS) are produced by hydrogenating SBS and SIS block copolymers, respectively, before they are recovered from the solution [3]. 

Weiss et al. [75] have synthesized Na and Zn salt of sulfonated styrene(ethylene-co-butylene)-styrene triblock ionomer. The starting material is a hydrogenated triblock copolymer of styrene and butadiene with a rubber mid-block and PS end-blocks. After hydrogenation, the mid-block is converted to a random copolymer of ethylene and butylene. Ethyl sulfonate is used to sulfonate the block copolymer in 1,2-dichloroethane solution at 50°C using the procedure developed by Makowski et al. [76]. The sulfonic acid form of the functionalized polymer is recovered by steam stripping. The neutralization reaction is carried out in toluene-methanol solution using the appropriate metal hydroxide or acetate. 

Here, we have demonstrated that it is possible to arrange successfully polystyrene microspheres with a diameter of 20 nm on each island (P4VP domain) of a PS-b- P4VP block copolymer film using hydrogen bonds. A 50 nm-large microsphere was rarely adsorbed to the PS-b-P4VP film. Since the present technique does not require an... 

Acid-containing polymers, hydrogen bonding, 260 Acrylic monomers photografting, 172,173/,174 UV curing, 212-213 Acrylic-acrylic block copolymers, synthesis, 259... 

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