Polystyrenes block copolymers

It has been reported that block copolymers with appropriately chosen partners and mixing ratios yield materials suitable for use in substrate disks for optical data storage. An example is polyarjiate—polystyrene block copolymer with a PS content between 40 and 60% (225). 

Puskas, J.E., Pattern, W.E., Wetmore, P.M., and Krukonis, A. Synthesis and characterization of novel six-arm star polyisobutylene-polystyrene block copolymers. Rubber Chem. TechnoL, 72, 559-568, 1999. Puskas, J.E., Wetmore, P.M., and Krukonis, A. Supercritical fluid fractionation of polyisobutylene-polystyrene block copolymers, Polym. Prepr., 40, 1037-1038, 1999. 

Kwon, Y., Antony, P., Paulo, C., and Puskas, J.E. Arborescent polyisobutylene-polystyrene block copolymers—a new class of thermoplastic elastomers, Polym. Prepr., 43, 266-267, 2002. 

Puskas, J.E. Dendritic (arborescent) pol3tisobutylene-polystyrene block copolymers DMTA analysis and swelling studies, Polym. Mater. Sci. Eng., 91, 875-876, 2004. 

Block copolymers were synthesized by a combination of fipase-catalyzed polymerization and atom transfer radical polymerization (ATRE). " " At first, the polymerization of 10-hydroxydecanoic acid was carried out by using lipase CA as catalyst. The terminal hydroxy group was modified by the reaction with a-bromopropionyl bromide, followed by ATRP of styrene using CuCE2,2 -bipyridine as catalyst system to give the polyester-polystyrene block copolymer. Trichloromethyl-terminated poly(e-CL), which was synthesized by lipase CA-catalyzed polymerization with 2,2,2-trichloroethanol initiator, was used as initiator for ATRP of styrene. 

Nakayama Y., Miyamura M., Hirano Y., Goto K., Matsuda T., Preparation of poly(ethylene glycol)-polystyrene block copolymers using photochemistry of dithiocarbamate as a reduced cell-adhesive coating material, Biomaterials 1999 20 963-970. 

Initial intrinsic viscosity, dl/g Free polyfmethyl acrylate) Free polystyrene Block copolymer... 

Chemically unlike polymers are incompatible, and it sometimes happens that the reaction medium is heterogeneous at the beginning. However, once some block copolymer is formed it acts as a "compatibilizer" and the reaction medium gradually becomes homogeneous. Many examples of such reactions could be quoted. A recent one is the hydrosilylation reaction carried out between a polystyrene fitted at a chain end with vinylsilane groups, and an a,u-dihydrogenopolydimethylsiloxane. This process is carried out at high concentration and it yields polystyrene-polydimethylsiloxane-polystyrene block copolymers. 2... 

Polystyrene-polybutadiene-polystyrene block-copolymers were also heparinized via formation of acetal bonds. The procedure involved oxidation of the copolymer to glycol 90) ... 

Chen, Gardella and Kumler106 have studied a series of polydimethylsiloxane-polystyrene block copolymers and examined the surface composition by ATR-FTIR and XPS. For AB-type PS-PDMS diblock copolymers (26) with siloxane block molecular weights of between 38,000 and 99,000, the surface was found to be exclusively polydimethylsiloxane down to a depth of 10 nm by XPS. ATR-FTIR, which samples... 

Koberstein and coworkers121 have examined the effects of a polydimethylsiloxane-polystyrene (PDMS-PS) block copolymer on the interfacial tensions of blends of PDMS and polystyrene. As little as 0.002 wt% of the copolymer, added to the siloxane phase, was sufficient to lower the interfacial tension by 82% in the case of a blend of polystyrene (Afn = 4,000) and PDMS (Mn = 4,500). No further reduction in interfacial tension was observed at higher copolymer levels due to micelle formation. Riess122 has polymerized styrene in the presence of a silicon oil and a polydimethylsiloxane-polystyrene block copolymer to obtain a polystyrene in which 0.1-1 pm droplets of silicone oil are dispersed. This material displayed a lowered coefficient of kinetic friction on steel compared to pure polystyrene. 

Polystyrene block copolymers and solubility in CO2 as a function of composition... 

QU2 Quintana, J.R., Salazar, R.A, and Katime, I., Micelle formation and polyisobutylene solubilization by polystyrene-Z>/oc -poly(ethylene-co-butylene)-Z>/ocA -polystyrene block copolymers, Macrowo/. Chem. Phys., 196, 1625, 1995. 

Table 18. Phase behavior of polystyrene block copolymers (Schemes 21, 22, 25). ...

Tong, J.D., Ni, S.R., Winnik, M.A., 2000. Synthesis of polyisoprene-b-polystyrene block copolymers bearing a fiuorescent dye at the junction by the combination of living anionic polymerization and atom transfer radical polymerization. Macromolecules 33 (5), 1482-1486. 

G. Dorff, M. Hahn, A. Laschewsky, A. Lieske, Optimization of the propoty profile of poly-L-ladide by synthesis of PLLA-polystyrene-block copolymers. J. Appl. Polym. Sci. 127 (2013) 120-126, doi 10.1002/app.37836. 

E. Kaul, V. Senkovskyy, R. Tkachov, V. Bocharova, H. Komber, M. Stamm, A. Kiriy, Synthesis of a Bifunctional Initiator for Controlled Kumada Catalyst- Transfer Polycondensation/Nitroxide-Mediated Polymerization and Preparation of Poly(3-Hexylthiophene)-Polystyrene Block Copolymer Therefrom. Macromolecules 2010,43,77-81. 

Schmidt-Naake, G. and Butz, S. 1996. Living free radical donor-acceptor copolymerization of styrene and N-cyclohexyl maleimide and the synthesis of poly[styrene-co-(N-chlohexylmaleimide)]/polystyrene block copolymers. Macrgmoleadat a i ... 

Morris, M.A. Polymer nanostructures in sub-micron lithographically defined channels film-thickness effects on structural alignment of a small feature size polystyrene-polyisoprene-polystyrene block copolymer. Soft Matter. 2007, 2, 916-921. 

Osmium tetroxide stained electron micrographs of polystyrene-Z>/ucA -polybutadiene-Z /ocA -polystyrene block copolymer produced by extrusion. (a) Micrograph demonstrating the orientation of the styrene cylinders in the direction of the extrusion (direction A in the schematic) and (b) shows a close-packed structure transverse to the extrusion direction (direction B in the schematic). Scale bar = 1 pm. 

Problem 11.16 A dual initiator, 4-hydroxy-butyl-2-bromoisobutyiate (HBBIB) was synthesized (Bernaerts et al., 2003) by the reaction of 1,4-butanediol with 2-bromoisobutyric acid using p-toluene sulfonic acid as catalyst in toluene. Suggest a scheme for the synthesis of well-de ned poly(tetrahydrofuran)-f>-polystyrene block copolymer with controlled molecular weights and low polydispersities using HBBIB. 

Figure 1. Segmental density fluctuation of alternating lamellae of pure polystyrene-b-polyisoprene-b-polystyrene block copolymer. The density (referenced to each pure segment composition) varies between 0 and 1 for each domain phase and in the interphase region which has finite thickness, d. The periodic pattern distance of the lamellae structure is denoted by D.

Electrical properties have been reported on numerous carbon fiber-reinforced polymers, including carbon nanoflber-modified thermotropic liquid crystalline polymers [53], low-density polyethylene [54], ethylene vinyl acetate [55], wire coating varnishes [56], polydimethyl siloxane polypyrrole composites [50], polyacrylonitrile [59], polycarbonate [58], polyacrylonitrile-polycarbonate composites [58], modified chrome polymers [59], lithium trifluoromethane sulfonamide-doped polystyrene-block copolymer [60], boron-containing polyvinyl alcohols [71], lanthanum tetrafluoride complexed ethylene oxide [151, 72, 73], polycarbonate-acrylonitrile diene [44], polyethylene deoxythiophe-nel, blends of polystyrene sulfonate, polyvinyl chloride and polyethylene oxide [43], poly-pyrrole [61], polypyrrole-polypropylene-montmorillonite composites [62], polydimethyl siloxane-polypyrrole composites [63], polyaniline [46], epoxy resin-polyaniline dodecyl benzene sulfonic acid blends [64], and polyaniline-polyamide 6 composites [49]. 

The Ripple Experiment Agrawaletal. (37) carried out what they called the ripple experiment, using neutron reflectometry on selectively deuterated polystyrene block copolymer chains in two layers. In one of the layers, the central 50% of the mers were deuterated, the two end 25% portions were normal, that is, bearing hydrogen. This material was denoted as HDH (1/4H-1/2D-1/4H). In the second layer, the chain labeling was reversed to make DHD (1/4D-1/2H-1/4D). The molecular weights of the two polymers were nearly identical, 2.25 x 10 g/mol, and 2.50 x 10 g/mol, respectively, synthesized by anionic polymerization to have narrow polydispersity indices. 

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