Polystyrene-poly graft

Figure 9.17 Plot of log [i ]M versus retention volume for various polymers, showing how different systems are represented by a single calibration curve when data are represented in this manner. The polymers used include linear and branched polystyrene, poly(methyl methacrylate), poly(vinyl chloride), poly(phenyl siloxane), polybutadiene, and branched, block, and graft copolymers of styrene and methyl methacrylate. [From Z. Grubisec, P. Rempp, and H. Benoit, Polym. Lett. 5 753 (1967), used with permission of Wiley.]...

Amphiphilic resin supported ruthenium(II) complexes similar to those displayed in structure 1 were employed as recyclable catalysts for dimethylformamide production from supercritical C02 itself [96]. Tertiary phosphines were attached to crosslinked polystyrene-poly(ethyleneglycol) graft copolymers (PS-PEG resin) with amino groups to form an immobilized chelating phosphine. In this case recycling was not particularly effective as catalytic activity declined with each subsequent cycle, probably due to oxidation of the phosphines and metal leaching. 

Poly(ethane-l,2-diyl/l-hydroxyethane-l,2-diyl) grafted with polystyrene [poly(l-phenylethane-l,2-diyl)] at hydroxymethylene units ... 

Fig. 6 Transmission electron micrograph (TEM) of the cross-section of a PDMAAm(poly-dimethylacrylamide)-b-PST(polystyrene) block-graft-copolymerized surface stained in iodine vapor, a Spurr s resin, b PST layer, c PDMAm layer, d dithiocarbamate (DC)-derivatized PST film...

Deters (14) vibromilled a blend of cellulose and cellulose triacetate. The acetic acid content of cellulose acetate decreased with grinding time (40 h) while that of the cellulose increased, suggesting the formation of a block or graft copolymer or of an esterification reaction by acetic acid developed by mechanical reaction. Baramboim (/5) dissolved separately in CO polystyrene, poly(methyl methacrylate), and poly(vinyl acetate). After mixing equal volumes of solutions of equivalent polymer concentration, the solvent was evaporated at 50° C under vacuum and the resultant product ball-milled. The examination of the ball-milled products showed the formation of free radicals which copolymerized. 

Some grafting between polystyrene and polyethylene may occur, but we think not. Substantial amounts of polystyrene (but not all) have been extracted from the blend samples by soaking the specimens in refluxing THF for several days. We suspect that if grafting does occur, it is not a significant contributor to polystyrene mass uptake. All the polystyrene could be extracted from a 50 wt % polystyrene/poly(4-methyl-l-pentene) (PMP) blend that was prepared by essentially the same procedure. The backbone of PMP (with two tertiary C —H bonds per repeat unit) is likely more susceptible to radical grafting than HDPE. 

Polymer-grafted silica (SiO2) particles represent one of the most popular colloidal systems with tunable interactions. Ilie chains of choice were mainly polystyrene, poly(dimethyl siloxane), poly(butyl methacrylate), and n-octadecyl or stearyl alcohol. Chain grafting provided the means to tailor the colloidal particle behavior from hard to soft, as well as introduce attractions in a controlled way by varying the temperature or adding non-absorbing polymer depletant [44,95-112]. 

Graft copolymers of A and B monomers are named poly(A-g-B) or poly -graft-po y B with the backbone polymer -(-A-) - mentioned before the branch polymer. Some examples are poly(ethylene-g-styrene) or polyethylene-gra/it-polystyrene and starch-gra/ir-polystyrene. In the nomenclature of block copolymers, b or block is used in place of g or graft, e.g. poly(A-b-B) or poly A-block-poly B, poly(A-6-B-6-A) or poly A-6/ocik-poly B-blocic-po y A, poly(A-b-B-6-C) or poly A-6/ock-poly B-block-po y C), and so on. Thus the triblock polymer (XXIV) is called poly(styrene-6-butadiene-b-styrene) or polystyrene-6/ocA -polybutadiene-6/ock -polystyrene. When such polymers are articles of commerce they are usually designated by the monomer initials thus, structure (XXIV) would be named SBS block copolymer. 

Some interest continues in absorber systems. Silane and styrene monomers have been copolymerised with 2-vinylphenyl benzotriazole stabilisers in order to graft the stabilisers into the polymer chain °. When doped into plastics materials they were found to exhibit high surface activity. However, there is a conflicting report from other workers on similar structures where it is claimed that such polymeric stabilisers do not photoprotect the surface of polystyrene . Poly(2,6-dimethyl-l,4-phenylene oxide) has been effectively stabilised with an ortho-hydroxyphenyl benzotriazole stabiliser while in another study these compounds are claimed to be lost rapidly from polycarbonates . Other types... 

Okano T, Yamada N, Sakai H, Sakurai Y. A novel recovery system for cultured cells using plasma-treated polystyrene dishes grafted with poly(N-isopropylacrylamide). J Biomed Mater Res 1993 27 1243-1251. 

Research in this area has resulted in the preparation of several comb polymers (Halasa, 1974 Folket al., 1044). The metallation technique is a useful and versatile method as it can be used with any polymeric material that contains a few double bonds. For example, ethylene-propylene was successfully grafted with norbornene. Similar reactions were performed on polymeric materials that contain aromatic rings, such as polystyrene, poly-a-methyl styrene, and polyphenylene oxide (PPO). 

V Polystyrene - poly(methylmethacrylate) copolymer (graft comb)... 

Another original example of the grafting to approach was reported by Lou et In this work, MWNTs were grafted by polystyrene, poly(s-caprolactone) (PCL) and their BCs by the addition reaction of the correspondent alkoxyamine-terminated precursors. 

Another kind of amphiphilic block copolymer-grafted MWCNTs was prepared by sequential ATRP of styrene and fBA using CNT-Br-1 as the initiator, followed by hydrolysis of the poly(tert-butyl acrylate) (P BA) block into PAA," as shown in Figure 5.12. The polymer amount of the second block can also be adjusted by the feed ratio of fBA to polystyrene (PS)-grafted MWCNTs, demonstrating the living characteristics of the block copolymerization. The core-shell amphiphilic nano-object can self-organize into a film at the interface of chloroform and water. 

The prefix g describes graft copolymers and the prefix b describes block copolymers. In this system of nomenclature, the first polymer segment corresponds to the homopolymer or copolymer that was formed during the first stage of the synthesis. Should this be a graft copolymer then this will represent the backbone polymer. For instance, if polystyrene is graft copolymerized with polyethylene, the product is called poly(ethylene-g-styrene). A more complex example can be poly (butadiene-co-styrene-g-acrylonitrile-co-vinylidine chloride). Similarly, examples of block copolymers would be poly(acrylonitrile- -methyl methacrylate) or poly(methyl methacry late- -acry lonitrile). 

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