Linear triblock copolymers

Linear triblock copolymers of the type styrene-butadiene-styrene (SBS) and styrene-isoprene-styrene (SIS) are produced commercially by anionic polymerization through sequential addition of monomers in the reaction chamber [10] as shown below ... 

Poly[(A)-s-(A )-s-(B)] three-arm star-block copolymer Poly[(A)2-s-(B)] three-arm star-block copolymer Poly[(A)2-s-(B)2] four-arm star-block copolymer Poly[(A)-b-(B)-b-(C)] linear triblock copolymer Poly[(A)-s-(B)-s-(C)] three-arm star-block copolymer N,N- Dimethylacetamide Anionic ring-opening polymerization... 

Since soluble multifunctional initiators are more readily available in cationic polymerization than in the anionic counterpart, ABA type linear triblock copolymers have been almost exclusively prepared using difunctional initiation followed by sequential monomer addition. The preparation and properties of ABA type block copolymer thermoplastic elastomers (TPEs), where the middle segment is PIB, have been reviewed recently [47]. 

We have further studied the synthesis of novel ABC linear triblock copolymers. Specifically, novel glassy(A)-fo-rubbery(B)-fo-crystalline(C) linear tri-... 

GPC fractionation and ozonisis of the products, the yield of cyclic polymer was estimated to be ca. 90%. The morphological transition of the cyclic block polymer depends on composition in essentially the same manner as that of the linear triblock copolymers, whereas the domain spacing of polystyrene-block-polyisoprene cyclic block copolymers were all smaller than those of the corresponding SIS linear triblock copolymers, which is attributed to looped chain conformation. 

Tang P, Qiu F, Zhang H et al (2004) Morphology and phase diagram of complex block copolymers ABC linear triblock copolymers. Phys Rev E Stat Nonlin Soft Matter Phys 69 031803... 

Zhu Y, Gido SP et al (2003) Microphase separation of cyclic block copolymers of styrene and butadiene and of their corresponding linear triblock copolymers. Macromolecules 36 148-152... 

Spherical micelles with a polybutadiene core were formed for a certain range of compositions of the mixed solvent. The equilibrium between micelles and nonas-sociated macromolecules was found to be consistent with a closed association mechanism. In comparison with a linear triblock copolymer, the star-block sample showed a lower aggregation number. 

Although the synthetic strategy using non(homo)polymerizable monomers has been shown to be highly effective for the synthesis of a variety of di- or triblock copolymers, ABA type linear triblock copolymers can also be prepared by coupling... 

The preparation of novel glassy(A)-b-rubbery(B)-l)-crystalline(C) linear triblock copolymers have been reported where A block is PaMeSt, B block is rubbery PIB, and C block is crystalline PPVL. The synthesis was accomplished by living cationic sequential block copolymerization to yield living poly(aMeSt-l)-IB) followed by site transformation to polymerize PVL [243]. In the first synthetic step, the GPC traces of poly(aMeSt-b-IB) copolymers with (w-methoxycarbonyl functional group exhibited bimodal distribution in both refractive index and UV traces, and the small hump at higher elution volume was attributed to PaMeSt homopolymer. This product was fractionated repeatedly using hexanes/ethyl acetate to remove homo PaMeSt and the pure poly(aMeSt-b-IB) macroinitiator was then utilized to initiate AROP of PVL to give rise to poly(aMeSt-b-IB-b-PVL) copolymer. 

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