Preparation of copolymers containing

Preparation of Copolymers Containing Both Electrophilic and Nucleophilic Groups. Our first implementation of this reaction scheme involved the preparation of a series of copolymers incorporating both a latent electrophile and an electron-rich aromatic moiety which, being phenolic, also provides access to swelling-free development in aqueous medium. The copolymers are prepared as shown in Figure 1 by copolymerization of 4-t-butyloxycarbonyloxy-styrene with 4-acetyloxymethyl-styrene. Although the reactivity ratios of these two monomers are different [11], our study of this system has confirmed that they copolymerize essentially in random fashion. 

Research Focus Preparation of copolymers containing perfluorosulfonate functions useful... 

A similar polymerization strategy afforded pBTCT in this case 2,5-trimethyl(stannyl)thieno[2,3- >]thiophene was utilized as the cross-coupling partner. For the preparation of copolymers containing... 

Polyaddition reactions based on isocyanate-terminated poly(ethylene glycol)s and subsequent block copolymerization with styrene monomer were utilized for the impregnation of wood [54]. Hazer [55] prepared block copolymers containing poly(ethylene adipate) and po-ly(peroxy carbamate) by an addition of the respective isocyanate-terminated prepolymers to polyazoesters. By both bulk and solution polymerization and subsequent thermal polymerization in the presence of a vinyl monomer, multiblock copolymers could be formed. 

Hydrosilation reactions have been one of the earlier techniques utilized in the preparation of siloxane containing block copolymers 22,23). A major application of this method has been in the synthesis of polysiloxane-poly(alkylene oxide) block copolymers 23), which find extensive applications as emulsifiers and stabilizers, especially in the urethane foam formulations 23-43). These types of reactions are conducted between silane (Si H) terminated siloxane oligomers and olefinically terminated poly-(alkylene oxide) oligomers. Consequently the resulting system contains (Si—C) linkages between different segments. Earlier developments in the field have been reviewed 22, 23,43> Recently hydrosilation reactions have been used effectively by Ringsdorf 255) and Finkelmann 256) for the synthesis of various novel thermoplastic liquid crystalline copolymers where siloxanes have been utilized as flexible spacers. Introduction of flexible siloxanes also improved the processibility of these materials. 

Other Methods for the Preparation of Siloxane Containing Copolymers... 

Equation 2 illustrates another route to prepare graft copolymers, involving the preparation of polyolefin containing para-methylstyrene groups (I1). 

More recently, Ueno et al. have prepared and investigated a new series of copolymers containing p-phenylazobenzyl-L-aspartate and n-octadecyl-L-aspartate residues (Scheme 7, Structure XII). 55 561 In the case of copolymers containing less than 50 mol% azo residues, the CD spectra at 25 °C were consistent with the presence of right-handed helical conformations, which were not affected by irradiation at 320 nm. In contrast, in the case of copolymers containing 68 and 89 mol% azobenzene groups, irradiation caused the reversal of helix sense from the left-handed to the right-handed form. 

Wang G, Tong X, Zhao Y. (2004) Preparation of azobenzene-containing amphiphilic diblock copolymers for light-responsive miceUar aggregates. Macromolecules 37 8911-8917... 

Palladium cross-coupling reactions of a-haloselenophenes are a useful tool for the preparation of selenophene-containing copolymers <2005PSA823, 2005MM244>. 

There are several reports in recent literature on the application of silicon-containing compounds as the initiators of cationic ring-opening polymerization. This apparently is related to the attempts to prepare block copolymers containing polysiloxane or polysilane segments. (CfL SiCFAgClCL system was used to initiate cationic polymerization of tetrahydrofuran... 

Hawker et al. prepared the 1-phenylethyl adduct of BPPN, i.e., 2,2,5-trime-thyl-3-(l-phenylethoxy)-4-phenyl-3-azahexane, (TMPAH, Fig. 13) and found that it was useful for the controlled homopolymerizations of St, nBA, acrylonitrile, and N,N-dimethylacrylamide [71]. For example, the homopolymerization of DMA resulted in polymers with Mn=4000-55,000 with Mw/Mn=l.15-1.21. TMPAH was also used to prepare random copolymers containing St or nBA and the above monomers, in addition to copolymers with MMA, acrylic acid, 2-hy-droxyethyl acrylate (HEA),and glycidyl acrylate. As with DEPN, it was necessary to add the free nitroxide to mediate the polymerization rate, but the resulting... 

Since the monomer I would copolymerize with a wide variety of comonomers with the introduction of an ester group into the main chain, this appeared to make possible the preparation of biodegradable addition polymers. Copolymerization of ethylene and the ketene acetal I at 120°C produced a series of copolymers containing ester groups in the backbone of the copolymer, again with quantitative ring opening. 

In order to ensure that the copolymers were reasonably homogeneous in view of the fact that the 2-methylene-l,3-dioxepane (I) is only slightly more reactive than ethylene, all conversions were held to below 2% as indicated in Table I. A series of copolymers containing from 2.1 to 10.4 mol-2 of the ester-containing units was prepared. 

The photolysis of copolymers containing ketone groups has both academic and practical interest since the way in which the polymeric environment affects the photochemical pathways leads to an understanding of the photodegradation of polymers in which the ketone group is present as an adventitious or intended impurity. Copolymers with vinyl ketones also provide a practical means for preparing plastics with controlled lifetimes as a means of combatting litter problems (1.-3). 

Hence, the insensitivity to addition sequence for styrene and (AA) monomers makes it relatively easy to form (PS-fc-PAA), (PS-fc-PAA-fc-PS), and (PAA-Z -PS-Z -PAA) di- and tiiblock copolymers. However, when AN and MMA are involved, the poly(acrylonittile) block must be formed first, i.e., second monomer addition should be in the order shown in the preceding text. Unlike NMP methods, the use of ATRP presents no major problems when preparing block copolymers containing acrylates and methacrylates. Triblock (ABC) copolymers can be prepared by starting with a bromine-terminated polystyrene macroinitiator to polymerize Z-butyl acrylate, followed by methyl acrylate or methyl methacrylate using a CuBr/pentamethyl diethylene triamine catalyst. 

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