Functionalization methods unreactive poly

This method involves the use of functional initiators with a protected or unprotected functional group. When the functional group is unreactive under the polymerization conditions, protection is not necessary. Functional vinyl ethers have extensively been used in the Bving cationic polymerizations of vinyl ethers and these functional poly(vinyl ethers) can be derivatized to the desired functionahty by simple organic reactions. Vinyl ethers carrying a variety of functional pendant groups, in a general form (Scheme 26.1) ... 

The extent of conversion during an acrylamide polymerization is most easily followed by determining the disappearance of the monomer. High performance liquid chromatography (hplc) is often found best for this purpose. An hplc method in which poly(acrylamide) inverse emulsions can be used directly has been developed (238). In the case of copolymers, hplc protocols that allow the simultaneous determination of all the unreacted monomers can be used to evaluate compositional drift as a function of conversion. 

By this chemistry, polymers with one amine end group as well as a,co-diamine-functionalized polymers can be used to prepare AB or ABA copolymers, respectively. The method gives copolymers with well-controlled polypeptide segments. Furthermore, no unreacted homopolymers or homopolypeptides could be detected. Several examples of the polymer B block have been reported poly(octenamer) prepared by acylic diene metathesis polymerization [67], poly(methyl acrylate) prepared by atom transfer radical polymerization (ATRP) [70], poly(ethylene glykol) PEG, and PDMS [68]. The method was expanded for the synthesis of... 

A more recent application of ultrasonics has been the characterization of the extent of polymerization in a condensation or radical process. The first observations were made by Sokolov, and subsequent reports of measurements on polystyrene, poly(vinyl chloride) and poly(vinyl acetate) " have confirmed the utility of the method. It is clear that this type of study is still in its infancy however, certain facts emerge which demonstrate the importance of this method. The compressibility of a solution containing monomer and polymer is directly related to the proportion of each component present. It is therefore possible to quantitatively estimate the extent of conversion from the observed velocity of sound. In a suspension polymerization, the glass transition of the polymer forming the bead is itself a function of the extent to which unreacted monomer is retained in the system. In this case, observation of the attenuation can indicate the extent to which polymerization has occurred in the system. Unfortunately the data are not sufficiently extensive to estimate the general validity of the method for the monitoring of polymerization in reactors, although the potential has been clearly demonstrated. 

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