Cationic graft copolymer Monomer

Lignin has been reacted with 4N,4N - dimethyl-4-ammoniumhept-1,6 -diene chloride monomer to make a cationic graft copolymer. The structure of the copolymer is illustrated by the formula ... 

The metallocene catalyst with cationic nature and spatially opened active site provides favorable condition for the incorporation of p-alkylstyrene (p-ms) to polyolefins. The p-ms groups can be easily metallated to produce "stable" polymeric anions for graft-from polymerization. With the coexist of anion-polymerizable monomers, we have prepared many graft copolymers, such as PE-g-PS, PE-g-PMMA, PE-g-PAN, PP-g-PS, PP-g-PB, PP-g-PI and PP-g-PMMA. 

Further studies verified the intermediate formation of free radicals, as demonstrated by the electron-spin resonance spectra obtained during autooxidation of cellulose,75 and hydrogen peroxide was identified as a byproduct in the autooxidation of D-glucitol. Similar oxidations of cellulose in the presence of alkenic monomers afforded graft copolymers. The autooxidation of cellulose and of the cello-oligosaccharides was shown to be more extensive in the presence of transition-metal cations. 

Other useful modifications include acetylation, hydroxyethylation, hydro-xypropylation, cationic starches, succinate, and substituted succinate derivatives of starch. In starch-grafted copolymers, free radicals are initiated on the starch that then act as macroinitiators for the acryl or vinyl monomers. These products are used in firefighting fluids, electrolyte solutions for alkaline batteries, wound dressing, and so on. 

The homopolymer of the pyridinium salt monomer readily initiates the cationic polymerization of BOE upon heating to around 120 °C, to yield grafted copolymers. The copolymer with styrene similarly catalyzed the polymerization to form the corresponding grafted copolymers. The initiation activity of the copolymer in the polymerization was higher than that of the homopolymer but lower than that of the low-molar mass analogue, N-benzyl-p-cyanopyridinium hexafluoroantimonate. 

N-Benzyl and iV-alkoxy pyridinium salts are suitable thermal and photochemical initiators for cationic polymerization, respectively. Attractive features of these salts are the concept of latency, easy synthetic procedures, their chemical stability and ease of handling owing to their low hygroscopicity. Besides their use as initiators, the applications of these salts in polymer synthesis are of interest. As shown in this article, a wide range of block and graft copolymer built from monomers with different chemical natures are accessible through their latency. 

Several graft copolymers were prepared by copolymerization of macromonomers described in the previous section. Another route-to-graft copolymer is based on conversion of suitable groups along the chain of preformed polymer into species capable of initiating the cationic ringopening polymerization of suitable monomer. Thus, for example, polym-... 

The production of graft copolymers from an initial polymer containing carbon-chlorine bonds, Et2AlQ and a monomer sensitive to cationic polymerisation seemed until recently the best indirect proof of Kennedy s initiation scheme ... 

The use of polymeric initiators or coinitiators to induce the polymerisation of a second monomer by a cationic mechanism is a particularly attractive possibility, since it would permit the synthesis of block and graft copolymers. The search for adequate systems in this context has been intensive, but only very recently has it met with some success, and this is far from being as spectacular as the achievements obtained in the same area with anionic systems. The main difficulties to be surmcwntedhave been discussed in the general introduction to this review (see Chap. I), and have to do with the ubiquity of transfer and termination reactions in cationic polymerisation. Nevertheless, the advances of the last few years seem encouraging and one would expect that the near future will provide considerable progress, both quantitative and qualitative. 

Trimethylsilyl triflate can initiate the cationic polymerization of different vinyl and heterocyclic monomers (28). The triflated poly silane can react in the same way and can induce growth of a large number of chains. In this way, comblike graft copolymers can be prepared. 

The present volume is particularly concerned with the use of the different modes of controlled radical polymerisation for the preparation of copolymers such as random copolymers, linear block copolymers, as well as graft copolymers and star-shaped copolymers. It also presents the combination of controlled radical polymerisation with non-controlled radical copolymerisation, cationic and anionic polymerisation,both of vinyl monomers and cyclic monomers, and ringopening metathesis polymerisation. 

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