Mechanical synthesis

Casale, A. and Porter, R. Mechanical Synthesis of Block and Graft Copolymers. Vol. 17, pp. 1-71. 

The first chapter of the book deals with leuco-spiropyrans and related spiro compounds, which constitute one of the classes of leuco compounds not of the redox type. Such materials are photochromic, and are of major technical importance. The author, Hiroyuki Nakazumi of the Department of Applied Chemistry at the University of Osaka Prefecture, is well known for his researches in functional dye chemistry, particularly photochromic materials, and he provides a very useful update of the field, covering mechanisms, synthesis, spectra and applications, together with a useful section on approaches to near-infrared absorbing photochromic dyes. 

K. Matyjaszewski (Ed.), Cationic Polymerizations Mechanisms, Synthesis and Applications, Marcel Dekker, New York, 1996. 

Matyjaszewski K (ed) (1996) Cationic polymerization. Mechanisms, synthesis and applications. Marcel Dekker, New York... 

Matyjaszewski, K. and C. Pugh, Introduction, Chap. 1 and Mechanistic Aspects of Cationic Polymerization of Alkene, Chap. 3 in Cationic Polymerizations Mechanisms, Synthesis, and Applications, K. Matyjaszewski, ed., Marcel Dekker, New York, 1996. 

Sawamoto, M., Prog. Polym. Sci., 16, 111 (1991) Controlled Polymer Synthesis by Cationic Polymerization, Chap. 5 in Cationic Polymerizations Mechanisms, Synthesis, and Applications,... 

Of all the methods for the production of block and graft polymers, the greatest importance, from the view of commercial simplicity, involves mechanical synthesis. The block and graft reactions can be potentially performed directly during polymer processing and in standard equipments, such as internal mixers, injection molding machines, and extruders. 

Another advantage of mechanical synthesis is the minor influence of production cost This allows the tailoring of polymers for specific needs of industry where small amounts of interpolymers of different composition are required. 

The mechanical synthesis of block and graft copolymer is a method of sizable versatility. It can be performed (as already stated) during polymer processing and in standard equipment. The reaction, also, can be carried out by subjecting a mixture of two or more polymers to mechanical degradation in either the solid, elastic-melt, or solution states. It is, also, possible to induce reaction mechanically between polymers and monomers. 

The structure of copolymers obtained by mechanical synthesis depends on the properties of the components at reaction conditions. By altering conditions, it is possible to regulate, within wide limits, the rate of polymer breakdown and thus influence the composition of resulting products. 

It is generally believed that the mechanical synthesis involves the following general steps with the composition of the resulting interpolymers depending cm the relative rates ... 

The picture of mechanical synthesis is much more complex if the segments of block and graft copolymers can undergo rupture to polymeric free radicals forming multisegment block copolymers, gelled and crosslinked structures. Baramboim in his book (if) describes 14 different possibilities of block ami graft reactions. 

The mechanical synthesis of block and graft copolymers by vibromilling a polymer-monomer blend has been performed by many researchers. Natural polymers (14,17) vinyl polymers (18—27), and heterochain polymers (18, 28-34) have been formed during polymer mechanochemical degradation. Importantly, Simionescu, Vasiliu-Oprea and Neguleanu studied the possibility of carrying out mechanically-induced polycondensations starting from polyesters and diamines (33,35-37). 

Table 8 summarizes the polymer-monomer systems investigated in mechanical synthesis in the solid state. 

Table 10. Mechanical synthesis of interpolymers by mastication of polymer blends...

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