Macromolecular compounds modification

The present chapter deals with the application of Mannich aminomethylation or Mannich bases to the synthesis and modification of macromolecular compounds. As summarized in Fig. 150, a remarkable number of different combinations exist, as the Mannich reaction enables us (a) to perform polymerizations by using bifunctional substrate and amine as well as (d) to functionalize polymeric derivatives behaving, alternatively, as substrate or amine components of Mannich synthesis. On the other hand, the manifold reactivity of Mannich bases makes it possible (b) to produce polymers by amino group replacement with bifunctional nucleophiles or to polymerize suitable moieties (e.g., double bonds) present in the base. Furthermore (e), macromolecular compounds can be subjected to amino group replacement as well as to various other reactions given by Mannich bases. Finally (c), crosslinked derivatives are obtained from oligomeric or polymeric products through any of the above mentioned methods. 

In order to obtain greater information about the composition of polymers and macromolecular material, modifications to the analytical pyrolysis process have been developed. These have included on-line pyrolysis hydrogenation of polyolefines using hydrogen carrier gas and a palladium catalyst. Polyacetals have been pyro-lyzed in the presence of a cobalt catalyst to produce cyclized compounds that afford greater information about the structure of the polymer. ... 

On the other hand, native cellulose is an abundant and inexpensive macromolecular compound that reinforces most plant cell walls. During recent years, attention has been devoted to the use of cellulose (nanocellulose or nanofibrillated cellulose), and important studies have been published [13-22]. The outstanding mechanical properties of nanocellulose or nanofibrillated cellulose, linked to its wide availability, biodegradability, and extensive number of alternatives for chemical modification, have been the driving force for its utilization as reinforcement in polymers. These cellulosic materials are composed of nanosized cellulose fibrils with a high aspect ratio (length-to-width... 

Chemical modification of polymers is the only way to obtain materials derived from natural macromolecular compounds (cellulose, starch) or polymers with no available monomer (poly(vinyl alcohol). Even when the monomer is available, chemical modification can be the only way to obtain its polymer thus, attempts at direct preparation of poly(epiiodohydrin) were unsuccessful but partial success was achieved by nucleophilic displacement of the chlorine atom of poly(epichlorohydrin) by sodium iodide in the presence of a small amount of methyltributylammonium in butanol. However, chemical modifications are increasingly used to synthesize new polymers with specific properties. 

This chapter is mainly devoted to organic compounds for which the observed reversible color changes (coloring and fading reactions) are due to the effect of temperature, exclusively. The thermochromic behavior of inorganics, organo-metallics, macromolecular systems (such as polythiophenes), or supramolecular systems (such as liquid crystals) and of molecular systems for which the observed thermochromism is due to external intervention (association with another species like a metal ion or a proton) or to modification of the medium by a thermal effect (thermosolvatochromism, for instance) are not reviewed in this chapter. 

The results imply a weak association to the non-extractable particulate matter based on non-covalent inter-actions for the observed DDT-related contaminants. The release of these compounds was initiated by the modification and degradation of the organic macromolecular matrix as well as of the inorganic material. 

The compatibilization strategies comprise (i) addition of a small quantity of cosolvent - a third component, miscible with both phases, (ii) addition of a copolymer whose one part is miscible with one phase and another with another phase, (iii) addition of a large amount of a core-shell copolymer - a compatibilizer-cum-impact modifier, (iv) reactive compounding that leads to modification of at least one macromolecular species that result in the development of local miscibility regions, and (v) addition of a small quantity of nanoparticles which influence blend structure similarly to particle-stabilized water/oil emulsions. 

Post-polymerisation modifications of polymer structures based on the thiol-ene reaction are important tools in macromolecular science because several thiol compounds bearing diverse functional groups can be introduced easily onto a polymer chain that bears non-activated mono-substituted double bonds as functional groups... 

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