Aldehyde-functional poly

Li et al. [120-124] presented a series of articles on surface modification of aldehyde-functional poly(methylstyrene) latex particles. The synthesis of the different latexes was carried ont by emulsifier-free emulsion polymerizations or by nsing anionic or cationic surfactants, initiated by different initiators, and followed by an in situ snrface oxidation catalyzed by copper (II) chloride and tert-butyl hydroperoxyde. Changing the oxidation degree alters the surface morphologies of the functional latexes. 

Carbohydrates are characterized by the presence of polyhydroxylic aldehyde or poly-hydroxylic ketone structures or polymers of such units. Sugars and polysaccharides have definite three-dimensional structures that are important for many biological functions. They are hydrophilic and thus easily accessible to aqueous reaction mediums. The chemistry of bioconjugation using carbohydrate molecules begins with an understanding of the building blocks of polysaccharide molecules. 

Aldol group transfer polymerization of ferf-butyldimethylsilyl vinyl ether [62] was initiated by pendant aldehyde functions incorporated along a poly(methyl methacrylate) (PMMA) backbone [63]. This backbone was a random copolymer prepared by group transfer polymerization of methyl methacrylate (MMA) and acetal protected 5-methacryloxy valeraldehyde. After deprotection of the aldehyde initiating group, polymerization proceeded by activation with zinc halide in THF at room temperature. The reaction led to a graft copolymer with PMMA backbone and poly(silyl vinyl ether) or, upon hydrolysis of the ferf-butyldimethylsilyl groups, poly(vinyl alcohol) branches. 

The feasibility of the two general methods for end-functionalization in cationic polymerization (Scheme 4) has been examined and confirmed with these monomers (for example, see Ref. 131). Thus, a wide variety of end-functionalized poly(vinyl ethers) are available, as summarized in Table 1 [30,47,81,82,108,116,117,131 -147]. Inspection of this table indicates that almost all of important end groups are covered, including hydroxyl, carboxyl, amino, and aldehyde. 

Zhu and coworkers have reported the synthesis of functionalized poly(vinyl alcohol) resins for use as scavengers [13]. This was achieved via inverse suspension polymerization along side epichlorohydrin as a cross-linker. These resins were found to have excellent swelling characteristics in DMF, CH3OH, dioxane, THF, CH2C12 and H20. These were then functionalized with glutaric aldehyde to provide a polymer-supported aldehyde (Scheme 8.8). 

The use and limitations of Atom Transfer Radical Coupling (ATRC) reactions including polyrecombination reactions for the preparation of telechelic polymers, segmented block copolymers, and polycondensates are presented. Specifically, the preparation of telechelic polymers with hydroxyl, aldehyde, amino and carboxylic functionalities, poly(/i-xylylene) and its block copolymers, and polyesters via ATRC process is described. The method pertains to the generation of biradicals at high concentration from polymers prepared by ATRP or specially designed brfunctional ATRP initiators. The possibility of using silane radical atom abstraction (SRAA) reactions, that can be performed photochemically in the absence of metal catalysts, as an alternative process to ATRC is also discussed. 

Polyparaphenylenevinylene based block copolymers are very interesting as model materials. Indeed poly((2,5-dialkyloxy)-l,4-phenylenevinylene) (DEH-PPV) can be obtained by Seigrist condensation in order to obtained low polydispersity polymer with one aldehyde function. From this route, NMRP and... 

The carrier can be organic (polylactic acid [PLA] - and poly(lactic-co-glycolic acid) [PLOA]" ) or inorganic (chitosan - poly(N-isopropylacrylamide) " hydrogelator silk protein pectin " hydrazide- and aldehyde-functionalized carbohydrates dextran hydroxyethyl methacrylate and silica ). 

Several years ago, we developed an original syntitetic route which allowed us to prepare poly(2,5-furylene vinylene) by the polycondensation between the methyl group and the aldehyde function of 5-methylfurfural in a strongly nucleophilic medium (4,3) ... 

Thus, it is possible to form the very reactive, aldehyde-functionalized polymers by functionalization of polymeric organolithium compounds with 4-morpholinecarboxaldehyde. The key to the success of this procedure is due to the formation of a stable, tetrahedral intermediate that does not decompose to form the aldehyde group until work-up with alcohol. Work-up with acidic methanol is the preferred procedure to prevent dimer formation from base-catalyzed aldol condensation, primarily for functionalizations of poly(dienyl)lithiums. 

RGaction with Other Aldehydes. Poly(acrylamide) reacts with glyoxal [107-22-2], C2H2O2, imder mild alkaline conditions to yield a polymer with pendent aldehyde functionality. 

Redox poly(aerolein) is one of the most reaetive polymers and susceptible to a number of modifieation reaetions that lead to high eonversions under mild conditions [9,11,37]. Containing one pendant aldehyde function per repetition unit - either free or masked -poly(aerolein) possesses funetional groups and can react basically in the following ways [37,39,40] ... 

Aldehyde-Functional Polysiloxane Synthesis. Poly (dimethylsiloxanes) containing 1-hexenyl-dimethylsiloxane end groups, DC 7691 (n = 200), DC 7692 (n = 100) and DC 7697 (n = 30), were dissolved in hexane or methylene chloride (1 g/ml) and the solutions were cooled to -20°C. Ozone was then bubbled through the solutions and then into a Nal solution to decompose any excess that had not been reacted and prevent its release to the atmosphere. Treatment of the reaction mixtures with ozone was stopped after the Nal solution developed a blue color indicating that all the unsaturation had been consumed. The reaction mixtures were then allowed to warm to room temperature and heated for one hour at 40 C with Zn powder/acetic acid (1 1 molar ratio) to convert the ozonized groups on the polymers to aldehyde groups. 

Other types of functionalized poly(3-alkylthiophene)s can be prepared in order to obtain polymeric materials with different chemical, optical, and electronic properties and different solubilities. The organozinc route has been used to synthesize poly thiophenes bearing a phosphonic ester functionality or functional groups such as bromine, ester, alcohol, and acetal-protected aldehyde as terminal groups of C-3-substituents, as illustrated in Scheme 11 [76]. 

Aldehydes can be protected as N,N-acetals, which are stable to highly basic reagents such as RLi. Therefore, the aldehyde function of 14 was treated with N,N -dimethylethylenediamine to convert it to a N,N-acetal-protected styrene (14e). ° Unlike the oxygen analogues, 14e was anionically polymerized without problem to afford a living polymer, which was stable in THF at -78 °C even after 24 h (Table 3). The protective group was quantitatively removed by acid hydrolysis with 2 N HCl in THF (Scheme 8). The SEC trace of the poly(14) thus obtained... 

Rubinshtein M, James CR, Young JL, Ma YJ, Kobayashi Y, Gianneschi NC, Yang J (2010) Facile procedure for generating side chain functionalized poly(a-hydroxy acid) copolymers from aldehydes via a versatile Passerini-t3 pe condensation. Org Lett 12(15) 3560-3563... 

Li, R, Xu, J., Wang, Q., and Wu, C. 2000. Surface functionalization of polymer latex particles 4. Taylor-making of aldehyde-fimctional poly(methylstyrene) latexes in an emulsifier-free system. Langmuir 16 4141-7. 

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