Functional groups pendant

Other commercially relevant monomers have also been modeled in this study, including acrylates, styrene, and vinyl chloride.55 Symmetrical a,dienes substituted with the appropriate pendant functional group are polymerized via ADMET and utilized to model ethylene-styrene, ethylene-vinyl chloride, and ethylene-methyl acrylate copolymers. Since these models have perfect microstructure repeat units, they are a useful tool to study the effects of the functionality on the physical properties of these industrially important materials. The polymers produced have molecular weights in the range of 20,000-60,000, well within the range necessary to possess similar properties to commercial high-molecular-weight material. 

The presence of alkali metal during reductive coupling practically prevents the synthesis of polysilanes with groups which can be easily cleaved under basic conditions, such as pendant alkoxy or amino substituents. Polysilanes with pendant functional groups are not known. We have recently discoverd a very efficient method of functionalization of polysilanes. 

Applying these methodologies monomers such as isobutylene, vinyl ethers, styrene and styrenic derivatives, oxazolines, N-vinyl carbazole, etc. can be efficiently polymerized leading to well-defined structures. Compared to anionic polymerization cationic polymerization requires less demanding experimental conditions and can be applied at room temperature or higher in many cases, and a wide variety of monomers with pendant functional groups can be used. Despite the recent developments in cationic polymerization the method cannot be used with the same success for the synthesis of well-defined complex copolymeric architectures. 

The Sonogashira adducts of halopyrimidines with pendant functional groups are good precursors for synthesizing condensed heteroaromatic compounds. Yamanaka s group prepared four different condensed heteroaromatics from further manipulations of such Sonogashira adducts. Those four condensed heteroaromatics are 5-oxo-7-pyrido[4,3- pyrimidine 88 [62], furo[2,3-... 

The same effect has been observed for the monoselective protection/modifica-tion of equivalently difunctional molecules [28]. The binding is only temporary for the duration of the reaction but permits the other pendant functional group to react in preference. An example of this was shown by Leznoff for the preparation of monoethers of symmetrical dihydroxy aromatic compounds [29]. Under conventional conditions such reactions are problematic, providing mixtures of mono and... 

Bioerodible polymers having pendant functional groups are of particular interest, since they are capable of covalent pro-drug formation. Acemoglu [60] prepared... 

The effective complexation of CD was also used for the preparation of side-chain polyrotaxanes [96-102], All of these side-chain systems are based on Method 4 or Method 5 (Figure 9) and were reported by Ritter and coworkers. For Method 4, the CD was threaded on to a small molecule bearing a functional group Y and with one end blocked, i.e., a hemirotaxane. The reaction of Y with X, a pendant functional group in a preformed polymer, gives thermally stable... 

Those containing pendant functional groups and only carbon atoms in the main chain (polyvinyl alcohol). 

This technique is based on the use of a linear polymer with pendant functional groups that can be activated to initiate the polymerization of a second monomer. Based on this definition, the linear precursor polymer can be considered as a multifunctional macromolecular initiator. The importance of the grafting from technique by cationic polymerization of the second monomer increased considerably with the advent of living cationic polymerization. The advantage is the virtual absence of homopolymer formation via chain transfer to monomer. 

Many cooperative interactions can be found between pendant functional groups in the nucleophile-containing polymers. Features of the cooperations are full of variety. The cooperative interaction is shown in poly(4(5)-vinyliniidazole), by Over-berger (70), in the earlier studies. 

II. POLYMERS WITH PENDANT FUNCTIONAL GROUPS A. General Methodology and Scope... 

The simplest examples of so-called functional or functionalized polymers are perhaps those with pendant functional groups. The introduction of pendant functional groups to synthetic polymers, in general, may be achieved by two methods (1) polymerization of monomers with pendant functional groups and (2) chemical transformation of the pendant groups in preformed polymers. Both of them involve advantages and disadvantages, and most of the currently available polymers of this type are pro-... 

Figure 3 Vinyl ethers with pendant functional groups for which living cationic polymerization is feasible. The numerals in brackets attached to each entry indicate reference numbers.

Reaction of growing polymers with the in-chain/pendant functional groups of other polymers ... 

Some recent syntheses employ the first method (A), where, for example, living cationic polymerizations of isobutene [222], (f-butyl)dimethylsilyl vinyl ether [223,224], and 2-methyloxazoline [225] are initiated from appropriate pendant functional groups. 

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