Macromonomers reactive groups

The emulsifier provides sites for the particle nucleation and stabilizes growing or the final polymer particles. Even though conventional emulsifiers (anionic, cationic, and nonionic) are commonly used in emulsion polymerization, other non-conventional ones are also used they include reactive emulsifiers and amphiphilic macromonomers. Reactive emulsifiers and macromonomers, which are surface active emulsifiers with an unsaturated group, are chemically bound to the surface of polymer particles. This strongly reduces the critical amount of emulsifier needed for stabilization of polymer particles, desorption of emulsifier from particles, formation of distinct emulsifier domains during film formation, and water sensitivity of the latex film. 

Living polymerization processes pave the way to the macromolecular engineering, because the reactivity that persists at the chain ends allows (i) a variety of reactive groups to be attached at that position, thus (semi-)telechelic polymers to be synthesized, (ii) the polymerization of a second type of monomer to be resumed with formation of block copolymers, (iii) star-shaped (co)polymers to be prepared by addition of the living chains onto a multifunctional compound. A combination of these strategies with the use of multifunctional initiators andtor macromonomers can increase further the range of polymer architectures and properties. 

The described novel synthetic process opens the way to a large number of new macromonomers. Of especially high interest are those derived from polar or unpolar substituted styrenes and such where the substituent is a reactive group. One prominent example is divinylbenzene (DVB), which, when catalytically converted... 

Table 15.13. Macromonomers by end-capping with compounds providing reactive groups...

Compatibilisers are intentional additives, incorporated into multi-component, multiphase polymer systems. They are usually block copolymers, whose segments are soluble in different components of the mixture. Compatibilisers can be reactive (if they form bonds with one of the polymers in the mixture) with reactive groups like acrylic or methacrylic, maleic anhydride, or glycidyl methacrylate), or non-reactive. The main classes of compatibilisers are (a) modified PE and polypropylene-styrene containing polymers, (b) macromonomers, (c) silane-modified materials. 

Poly (ethyl vinyl ether) (PEVE) macromonomers were also prepared using initiator 5 bearing an allylic function [148]. This reactive group remained intact during the polymerization and could be transformed into the corresponding oxirane by peracid oxidation. 

To the first category belong the homo- and copolymerization of macromonomers. For this purpose, macromolecules with only one polymerizable end group are needed. Such macromonomers are made, for example, by anionic polymerization where the reactive chain end is modified with a reactive vinyl monomer. Also methacrylic acid esters of long-chain aliphatic alcohols or monofunctional polyethylene oxides or polytetrahydrofurane belong to the class of macromonomers. 

A second test was done by using butyl acrylate as the comonomer as shown in Figure 11. The reactivity ratios in this case are such that the methacrylate functionality would react slower with acrylates than with vinyl chloride. As predicted the butyl acrylate is at 62% conversion before the MACROMER peak is significantly diminished. These data add validity to the hypothesis that the placement of side chains in the backbone is dependent on the terminal group of the macromonomer and the relative reactivity of its comonomer. 

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