Polystyrene copolymers synthesis

An interesting application of the Paal thiophene synthesis was documented for the synthesis of a polystyrene-oligothiophene-polystyrene copolymer. In the Stetter reaction of aldehyde 13 and P-dimethylaminoketone 14, in situ generation of the a,p-unsaturated ketone preceded nucleophilic 1,4-conjugate addition by the acyl anion... 

Hydrosilylation was successfully applied to block copolymer synthesis. Polystyrene with two H—Si end groups derived from the polystyrene dianion and di-... 

Polystyrene-polyamide block copolymer synthesis 63> also involves some kind of site transformation. The polystyrene precursor is fitted at chain end with a function... 

E Bayer, M Dengler. B Hemmasi. Peptide synthesis on the new polyoxyethylene-polystyrene graft copolymer, synthesis of insulin B21.30. btt J Pept Prot Res 25, 178, 1985. 

The methods for oligomerization of the peptoid monomers are broadly based on the techniques developed for solid-phase peptide synthesis. A number of modifications are necessary, since difficulties are often encountered with N-alkyl amino acids for example, proHne and other N-alkylamino acids often couple poorly under standard conditions. Currently a wide range of functionalized polystyrenes and polystyrene copolymers is available. The immobilized functional group typically is an amino, carboxy, halo, hydroxy, or phosphino group. The polymer is joined to the... 

Block Copolymer Synthesis by Three-Step Sequential Monomer Addition The preparation of block copolymers by sequential addition of monomers using living anionic polymerization and a monofunctional initiator is the most direct method for preparing well-defined block copolymers. Detailed laboratory procedures for anionic synthesis of block copolymers are available [37, 230], Several important aspects of these syntheses can be illustrated by considering the preparation of an important class of block copolymers (Scheme 7.22), the polystyrene-fe-polydiene-( -polystyrene triblock copolymers. 

Frenz C, Fuchs A, Schmidt HW, Theissen U, Haarer D. 2004. Diblock copolymers with azobenzene side groups and polystyrene matrix synthesis, characterization and photo addressing. Macromol Chem Phys 205 1246 1258. 

Ban, H. T. Tsunogae, Y. Shiono, T. Synthesis and characterization of cw-polybutadiene-Wuck-syn-polystyrene copolymers with a cyclopentadienyl titanium trichloride/modified methylaluminoxane catalyst. J. Polym. Sci., Part A Polym. Chem. 2004, 42, 2698-2704. 

Scheme Pll.5.1 Graft copolymer synthesis random copolymer of styrene and ethyl acrylate grafted onto polystyrene (Problem 11.5). (Drawn following the synthesis method of Hawker, 1995.)...

These losses contribute to heat buildup in the tire and consequent loss in properties such as strength and tear resistance. Since the losses increase with temperature below 100 C the rate of heat generation also increases with temperature, a very unstable situation for tires. This situation also dooms the use of polystyrene-b-polyisoprene-b-polystyrene polymers with low end-block concentrations. In terms of other physical properties, there is no compelling reason to believe that vulcanized block copolymers would be Inferior to other tire rubbers. What limits their consideration here is most likely the higher cost of the block copolymer synthesis. 

IDestarac, M., Pees, B., and Boutevin, B. (2000). Radical telomerization of vinyl acetate with chloroform. Application to the synthesis of poly(vinyl acetate)-block-polystyrene copolymers by consecutive telomerization and atom transfer radical polymerization. Macromol. Chem. Phys., 20/(11) 1189 1199. 

Fig. 4.15 Schematic of synthesis of amphiphilic hyperbranched poly(acrylic acid) grafted with short polystyrene copolymer chains (HB-PAA-g-PS) and their linear triblock PS-PAA-PS...

Kee, R.A. and Gauthier, M. (2002) Arborescent polystyrene-gra -poly(2-vinylpyridine) copolymers Synthesis and enhanced polyelectrolyte effect in solution. Macromolecules, 35,6526-6532. 

Gao, H, Gaffney, B L., and Jones, R. A. (1991) H-Phosphonate oligonucleotide synthesis on a polyethylene glycol/polystyrene copolymer. Tetrahedron Lett. 32,5477-5480. 

Another example for block copolymer synthesis is the preparation of poly (methylene-fc-styrene), which was achieved by using a hydroxyl-terminated living polystyrene obtained by TEMPO-mediated living radical polymerization [75] (Scheme 55). The chain end hydroxyl group was transformed into an allyl ether moiety, which was subjected to hydroboration with BH3 to afford polystyrene macroinitiator for the polymerization of 11. After chain elongation with 11 oxi-dation of the C-B chain ends furnished poly(methylene- -styrene) bearing TEMPO and hydroxyl group at chain ends. 

Danishefsky has developed a solid phase oligosaccharide synthesis strategy based on glycals which are bonded to a polystyrene copolymer via silyl ether bonds and coupled to other glycals. The products were released by use of tetrabutylammonium fluoride. ... 

Based on this reaction, solid-phase library synthesis of tri- and tetracyclic scaffolds was developed by using Tenta-Gel resin (a poly(ethyleneglycol)-polystyrene copolymer) derivatized with a photolabUe linker as a solid support. Because of an epoxy functionality, the TiCLi-catalyzed trans-esterifcation used in the solution-phase reaction had to be replaced with a direct acylation by using a coupling reagent. Resin-bound epoxycyclohexenol 121 was reacted with the nitrone carboxylic acid 122 in the presence of PyBroP to form a nitrone cyclohexenyl ester intermediate that was... 

Enzymatic ROP has also been successfully combined with chemically catalyzed polymerization methods in SCCO2, allowing the formation of block structures. For example, Howdle and coworkers reported a simultaneous use of Novozym 435 with metalblock copolymers of PCL and PMMA [107, 108], whilst a two-step methodology was used to form block copolymers of PCL with poly(fluoro-octyl methacrylates) (PFOMA) [109]. Similar reactions, simultaneously combining reversible addition-fragmentation chain transfer (RAFT) with enzymatic ROP to form block copolymers of polystyrene and PCL, have also been performed in SCCO2 [110]. Block copolymer synthesis in SCCO2 has recently been reviewed [111]. 

A research group in Lehigh University has extensively studied the synthesis and characterization of uniform macroporous styrene-divinylbenzene copolymer particles [125,126]. In their studies, uniform porous polymer particles were prepared via seeded emulsion polymerization in which linear polymer (polystyrene seed) or a mixture of linear polymer and solvent were used as inert diluents [125]. The average pore diameter was on the order of 1000 A with pore volumes up to... 

Ion coupling of anionic and cationic living polymers is an interesting procedure for the synthesis of a well-defined block copolymer. Attempted coupling of the polystyrene anion with the poly-THF cation initiated by triethyloxonium tetrafluoro-borate yielded a block copolymer mixed with homopolymers394. The block ef-... 

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