Technical Review - Monomers

Homogeneous GopolymeriZation. Nearly all acryhc fibers are made from acrylonitrile copolymers containing one or more additional monomers that modify the properties of the fiber. Thus copolymerization kinetics is a key technical area in the acryhc fiber industry. When carried out in a homogeneous solution, the copolymerization of acrylonitrile foUows the normal kinetic rate laws of copolymerization. Comprehensive treatments of this general subject have been pubhshed (35—39). The more specific subject of acrylonitrile copolymerization has been reviewed (40). The general subject of the reactivity of polymer radicals has been treated in depth (41). 

This review focuses on some technical and practical aspects of the pyrolysis or thermal cracking of waste plastics, to yield liquid fuels and monomers as a main product. It... 

The absence of control of the incorporation of monomers into the polymeric chain implies that many macroscopic properties carmot be influenced to a large extent. Therefore, much effort has been directed toward the development of controlled radical polymerization (CRP) methods for the preparation of various copolymers (for a review, see Reference 31). CRPs offer the possibility of producing polymers with relatively well-defined properties, while at the same time maintaining the simplicity of radical processes.These methods are based on the idea of establishing equilibrium between the active and dormant species in solution phase. In particular, the methods include three major techniques called stable free-radical polymerization, degenerative chain transfer technique, and atom transfer radical polymerization, pioneered by Ando et and Matyjaszewski et Although such syntheses pose significant technical problems, these difficulties have all been successively overcome in the past few years. Nevertheless, the procedure of preparation of the resultant copolymers with controlled monomer sequence distribution remains somewhat complicated. 

Maiti et al. [2] thoroughly reviewed the technical literature up to the late 1980s related to the use of rosin and its derivatives as monomers or co-monomers in a variety of polymerization systems, as well as the properties of the ensuing polymers. Most of the documents cited in this monograph were patents unavailable to us, whose scientific content was therefore difficult to judge, but nonetheless, the interest of this survey lies in the fact that it emphasizes the extensive search of materials based on rosin. Some clear-cut investigations in this context are described here as typical examples of the exploitation of rosin and its derivatives as polymer precursors. 

Vinylpyridines can be copolymerized radically with numerous common monomers. In many copolymerizations vinylpyridines are used in small quantities only. The most important technical product is a terpolymer from 1,3-butadiene (70 to 80% by weight), styrene (10 to 15%, and 10 to 15% of 2-vinylpyridine) [606]. Copolymers of methacrylic esters of long-chain alcohols and vinylpyridine have been applied as an oil additive. This and other applications for vinylpyridine copolymers are reviewed in detail in Ref. [607]. Copolymerization parameters are listed in Refs. [543,545,608,609] some of the newer results are given in Tables 5 and 6. 

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