Copolymer polystyrene-polydimethylsiloxane

The use of small amounts (0.5-3%) of polyethylene-polydimethylsiloxane or polystyrene-polydimethylsiloxane block copolymers in blends with a host... 

Polystyrene-polydimethylsiloxane (PDMS) triblock (or multiblock) copolymers 123) can be made by hydrosilylation involving a vinyl silane terminated polystyrene and a PDMS fitted at both chain ends with Si—H groups. The former species is ob-... 

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... 

Table II. Effect of Polystyrene Block Size on Mechanical Properties of Compression Molded Polystyrene-Polydimethylsiloxane Block Copolymers Containing 30% Polystyrene...

Melt viscosity increases as the molecular weight of the polystyrene blocks is increased, but the effect tends to diminish as the rate of shear is increased. The influence of block size is expressed as a family of converging viscosity—shear rate curves for three copolymers of differing block size, (Figure 3). These curves also illustrate the non-Newtonian character of the polystyrene-polydimethylsiloxane block copolymers. The effect of changing block size cannot be expressed as a single master curve as in the case of overall molecular weight. Such master curves must be based on polymers of constant block size. 

Hydrophobic blocks that are used for polymersome fabrication are inert polyethylethylene, polybutadiene, polystyrene, polydimethylsiloxane, degradable poly(lactic acid) (PLA), and poly(e-caprolactone) (PCL). Hydrophilic blocks include negatively charged poly(acrylic acid) and cross-linkable poly-methyloxazoline. Neutral PEG is more common for bioapplications. Among block copolymers, PEO-PLA and PEO-PCL are becoming widely adopted [26]. 

S. Ndonl, M. E. Vigild, and R. H. Berg, "Nanoporous Materials with Spherical and Gyroid Cavities Created by Quantitative Etching of Polydlmethylsiloxane in Polystyrene-Polydimethylsiloxane Block Copolymers,"/Am. Chem.Soc. 125,13366-13367 [2006]. 

Dumelow (123) used SEC-LALLS with dual concentration detectors to study the variation in compositional heterogeneity with molecular weight in polystyrene-polydimethylsiloxane block copolymers. The results showed that some of the copolymers were in fact blends. The largest errors in the analysis... 

These interaction parameters were determined in order to establish the compatibility of polymer blends and of chains of block copolymers. There are also determinations for blends poly(vinylchloride)-poly-e-caprolactone [27], polystyrene-poly (vinyl methyl ether) [28], polystyrene--polydimethylsiloxane above (120—180°0) and below (50—80°0) the glass... 

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. 

The most promising approach for preparing block copolymers of polystyrene (A) and polydimethylsiloxane (B) involves polymerization of cyclosiloxane monomers with living a,polystyrene anions (6). The original approach, however, gives materials contaminated with the... 

Several polymers were evaluated in the form of a surface coating on glass beads packed in columns to determine their ability to retain platelets when whole human blood passes over the surface. This ability was measured as the platelet retention index p, the fraction of platelets retained on the column. Lowest values of p were found for poly(ethylene oxide), polypropylene oxide), poly(tetramethylene oxide) (in the form of polyurethanes), and polydimethylsiloxane. Highest values (around 0.8) were found for cross-linked poly(vinyl alcohol) and the copolymers of ethylenediamine with diisocyanates. Intermediate values were found for polystyrene and its copolymers with methyl acrylate, for polyacrylate, and for poly(methyl methacrylate). The results are interpreted in terms of possible hydrophobic and hydrogen bonding interactions with plasma proteins. 

We may find confirmation for our statement about the thermodynamic incompatibility of linear polystyrene with the styrene-DVB copolymer in experiments by Wong et al. [269]. These authors reported similarities in the phase separation power of linear polystyrene and that of linear styrene-methylmethacrylate copolymer, the latter being a priori incompatible with the styrene-DVB network. Complete incompatibility of polystyrene with linear polydimethylsiloxane facihtates phase separation and results in the formation of a porous styrene-DVB network on adding as little as 0.5-1% of the above porogen to the initial comonomer mixture (Fig. 3.2, curves 4). It is also not surprising that the porosity of copolymers induced by linear polystyrene and linear polydimethylsiloxane is almost the same when the DVB content exceeds 10%. At a DVB content that hi, the network formed differs fundamentally from linear polystyrene, as from any alien polymer. 

Living anionic ROP of strained silicon-bridged [l]ferrocenophanes (Section 3.3.3) provides an excellent route to PFS block copolymers with controlled block lengths and narrow polydispersities (PDI<1.1) [82-84]. Diblock, triblock, and more complex architectures are now known for a wide variety of organic, inorganic, or even other polyferrocene coblocks. The prototypical materials prepared in the mid-1990s were the diblock copolymers polyferrocenylsUane-h-polydimethylsiloxane (PFS-fo-PDMS) 3.52 and polystyrene-b-polyferrocenylsUane (PS-i -PFS) 3.54 83j. As shown in Scheme 3.4, initial anionic polymerization of monomer 3.21... 

Decamethylcyclopentasiloxane Dimethicone/mercaptopropyl methicone copolymer Dimethoxymercaptopropyl-terminated polydimethylsiloxane homopolymer (Mercaptopropyl) methylsiloxane-dimethylsiloxane copolymer PEG-8 isolauryl thioether hair creams/lotions Human placental protein hair dressing Corn (Zea mays) oil hair fixative, hair sprays VA/crotonates copolymer VA/crotonates/vinyl propionate copolymer hair fixative, setting lotions Sodium polystyrene sulfonate , VA/crotonates copolymer hair lacquer resin MDM hydantoin hair lotion Quassia hair perms Ammonium bisulfite... 

Nonyl nonoxynol-150 Polystyrene Sodium tetraborate pentahydrate Vinyl chloride/vinylidene chloride copolymer paper, food-packaging Ceteareth CIO-12 pareth-3 CIO-12 pareth-6 CIO-12 pareth-8 Cl2-14 pareth-1 C12-14 pareth-3 C12-14 pareth-4 C12-14 pareth-7 C12-14 pareth-8 C12-14 pareth-11 Methyl hydrogenated rosinate Nonyl nonoxynol-7 Octoxynol PEG/PPG-35/9 copolymer PEG/PPG-125/30 copolymer PEG-14 tallate PEG-3.5 tetramethyl decynediol Petroleum distillates Polydimethylsiloxane Potassium N-methyldithiocarbamate Rosin, polymerized Tall oil glycerides paper, impregnating Terpene resin paper, light-sensitive Copper nitrate (ic) paper, machine-coated Starch... 

Satti, A. J. Ciolino, A. E. Villar, M. A. Schmidt, V. Giacomelli, C., Micelles Formed by Highly Asymmetric Polystyrene-i-Polydimethylsiloxane and Poly-styrene-b-poly[5-(N,N-diethylamino)isoprene] Diblock Copolymers. Langmuir 2010, 26,14494-14501. 

Malik, M. 1. Sinha, P. Bayley, G.M. Mallon, P. E. Pasch, H., Characterization of Polydimethylsiloxane-Block-Polystyrene (PDMS-B-Ps) Copolymers by Liquid Chromatography at Critical Conditions. Macromol. Chem. Phys. 2011, 212,1221-1228. 

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