Poly diblock copolymer synthesis

Wang, Y.B. and Hillmyer, M A. (2001) Polyethylene-poly(L-lactide) diblock copolymers Synthesis and compatibiliza-tion of poly(L-lactide)/polyethylene blends. Journal of Polymer Science Part A Polymer Chemistry, 39,2755 2766. 

Liu et al. prepared palladium nanoparticles in water-dispersible poly(acrylic acid) (PAA)-lined channels of diblock copolymer microspheres [47]. The diblock microspheres (mean diameter 0.5 pm) were prepared using an oil-in-water emulsion process. The diblock used was poly(t-butylacrylate)-Wock-poly(2-cinna-moyloxyethyl) methacrylate (PtBA-b-PCEMA). Synthesis of the nanoparticles inside the PAA-lined channels of the microspheres was achieved using hydrazine for the reduction of PdCl2, and the nanoparticle formation was confirmed from TEM analysis and electron diffraction study (Fig. 9.1). The Pd-loaded microspheres catalyzed the hydrogenation of methylacrylate to methyl-propionate. The catalytic reactions were carried out in methanol as solvent under dihydro-... 

In this review, synthesis of block copolymer brushes will be Hmited to the grafting-from method. Hussemann and coworkers [35] were one of the first groups to report copolymer brushes. They prepared the brushes on siUcate substrates using surface-initiated TEMPO-mediated radical polymerization. However, the copolymer brushes were not diblock copolymer brushes in a strict definition. The first block was PS, while the second block was a 1 1 random copolymer of styrene/MMA. Another early report was that of Maty-jaszewski and coworkers [36] who reported the synthesis of poly(styrene-h-ferf-butyl acrylate) brushes by atom transfer radical polymerization (ATRP). 

We reported the synthesis of Si/Si02//PS-h-poly(acrylate) tethered diblock copolymer brushes [31,32,46,47]. The properties of these diblock brushes were studied using water contact angles, ellipsometry. X-ray photoelectron spectroscopy (XPS), FTIR spectroscopy and atomic force microscopy (AFM). For a sample with a 26 nm PS layer and a 9 nm PMMA layer, the advanc-... 

Scheme 2 Synthesis of poly(IB-b-St) and poly(St-b-IB) diblock copolymers via sequential monomer addition...

The synthesis of poly(IB-fr-pivalolactone (PVL)) diblock copolymers was also recently accomplished by site-transformation of living cationic polymerization of IB to AROP of PVL, as shown in Scheme 14 [96, 97]. First, PIB with ffl-carboxylate potassium salt was prepared by capping living PIB with DPE followed by quenching with 1-methoxy-1-trimethylsiloxy-propene (MTSP), and hydrolysis of -methoxycarbonyl end groups. The -carboxyl-... 

A similar technique was employed for the synthesis of miktoarm stars having PS, PEO, poly(e-caprolactone) (PCL) or PMMA branches [57]. A PS-h-PMMA diblock copolymer possessing a central DPE derivative, bearing a protected hydroxyl function was prepared. After deprotection and transformation of the hydroxyl group to an alkoxide the anionic ring opening polymerization of the third monomer (EO or e-CL) was initiated. Only limited characterization data were given in this communication. 

In this system using a polystyrene containing block copolymer, the polystyrene segment should readily partition into the lipophilic polystyrene particle core while the poly(FOA) or PDMS block is solubilized in the CO2 continuous phase to provide steric stabilization and prevent coagulation. In comparison of the polystyrene-b-poly(FOA) diblock copolymers to the polystyrene-b-PDMS diblock copolymers, it was found that the use of a polystyrene-b-PDMS stabilizer gives much more monodisperse particles. This most likely arises from the synthetic technique employed in the surfactant synthesis. The blocks in the polystyrene-b-PDMS block copolymers have a much narrower polydispersity than the blocks in the polystyrene-b-poly(FOA) block copolymers. It was noted that the particles obtained in... 

Investigations were mainly devoted to the synthesis of telechelic polymers and copolymers rather than to living radical polymerization. In particular, from 1960, Imoto et al. [234] started surveys on the synthesis of block copolymers from this method. Thus, polystyrene-i>-poly(vinyl alcohol) diblock copolymer... 

Fig. 22 Synthesis of amphiphilic diblock copolymers of poly(l,l-dimethyl-2,2-dihexyldisilene)-i>-poly(2-hydroxyethyl methacrylate). Reproduced with permission from [48] Sanji et al. (1999) Macromolecules 32 5718. American Chemical Society...

Se et al. presented the synthesis of poly[(VS- -I)-b-S] block—graft copolymers.157 The backbone, a diblock copolymer of 4-(vinyldimethylsilyl)styrene (VS) and styrene, was prepared first by anionic polymerization. The VS monomer was polymerized selectively through the styryl double bond at low... 

Synthesis of poly(styrene-6-tBuA) diblock copolymer... 

Gitsov et al 10) produced a nanoreactor fi om laccase and linear poly(ethylene oxide)-dendritic poly(benzyl ether) diblock copolymers. A notable feature of this system is the presence of hydrophobic dendritic pockets that increase the local concentration of water-insoluble organic compounds near the active site where they are oxidized. Li and Hsieh (77) employed a hydrogel fiber membrane, with a large surface area and improved organic solvent solubility in order to facilitate lipase reactions. He (72) grafted lipase onto silica particles, which permitted him to carry out synthesis of polyesters, polycarbonates, polyphosphates, and their copolymers at temperatures up to 150°C. 

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