Polymerization and Functionality

Polymerization may occur only if the monomers involved in the reaction have the proper functionalities. Functionality is a very useful concept in polymer science. The functionality of a molecule is the number of sites it has for bonding to other molecules under the given conditions of the polymerization reaction (Rudin, 1982). Thus, a bifunctional monomer, i.e., a monomer with functionality 2, can link to two other molecules under suitable conditions. Styrene, C6H5CH=CH2, for example, has functionality 2 because of the presence of a carbon-carbon double bond. The minimum functionality required for polymerization is 2. 

A polyfiinctional monomer is one that can react with more than two molecules under the conditions of the polymerization reaction. Thus, divinyl benzene (VJlll) is tetrafunctional in reactions involving additions across carbon-carbon double bonds, while glycerol (IX) is trifunctional and pentaerythritol, C(CH20H)4, is tetrafunctional in polyesterification reactions. 

Functionality in polymerization is, however, defined only for a given reaction (Rudin, 1982). Thus, a glycol, HOROH, has a functionality of 2 in esterification or ether-forming reactions, but its functionality is zero in amidation reactions. 

Problem 1.2 What is the functionality of the following monomers in reactions with (i) styrene, CfiH5CH=CH2 and (ii) adipic acid, HOOC(CH2)4COOH  

The process of transformation of monomer molecules to a polymer molecule is known as polymerization. It is a chemical reaction in which the product molecules are able to grow indefinitely in size so long as reactants are supplied and suitable conditions exist. Polymerization may occur if the monomers involved in the reaction have the proper functionalities. 

A polyfunctional monomer is one that can react with more than two other molecules under the conditions of the polymerization reaction. Examples are divinyl benzene  

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Meanwhile, the R-R coupling (see Sect. 2.2) has evidently found general acceptance as the main reaction path for the electropolymerization of conducting polymers The ionic character of the coupling species explains why polar additives such as anions or solvents with high permittivity accelerate the rate of polymerization and function as catalysts. Thus, electropolymerization of pyrrole is catalyzed in CHjCN by bromide ions or in aqueous solution by 4,5-dihydro-1,3-benzenedisulfonic acid The electrocatalytic influence of water has been known since the work... 

This chapter surveys the polymerization of substituted acetylenes focusing on the research during this decade. Monomers and polymers, polymerization catalysts, controlled polymerizations, and functional polyacetylenes are discussed. Readers are encouraged to access other reviews and monographs on the polymerization of substituted acetylenes, and a,cj-diynes. ... 

An equimolar mixture of epoxide and cyclic anhydride has the stoichiometry of a polyester. Fisher47 has shown that if a tertiary amine is added to such a mixture, maintained at 70-100 °C, epoxide and anhydride disappear at identical rates to yield polyester. This relationship held even if the epoxide was present in excess. The excess could be removed at the end of the polymerization and functioned purely as solvent. 

The concentration of resonances in fully protonated water samples is on the order of 110 M, which vastly exceeds even the most optimistic biological samples. Even if the solubility of a subject protein were such that solute signal could be on par with the solvent, any subsequent work would be hindered by concerns of nonspecific binding, dimerization (or higher order polymerization), and functional relevance in any of these cases. Of course the more obvious problem would be the difficulty in obtaining and purifying enough sample (see Appendix), often labelled via expression in expensive N, and possibly even H-enriched media, to create such a hypothetical sample. As the solubility of almost any sample can never come close to these concentrations, suppression of the solvent becomes inescapable. 

Lu W, Chen M, Wu L (2008) One-step synthesis of oigtinic-inoiganic hybrid asymmetric dimer particles via miniemulsion polymerization and functionalization with silver. J Colloid Interface Sd 328 98-102... 

Deanna L. Pickel joined the research staff at the Center for Nanophase Materials Science at Oak Ridge National Laboratory in July 2007. Her research interests are in the precise synthesis and characterization of well-defined materials, both in functionality and in architecture, to better understand the relationship between molecular structure and self-assembly at the nanoscale. In particular, she is interested in the use of MALDI-TOF MS to better understand the mechanism of various polymerization and functionalization chemistries. Deanna received her BS in chemistry and BA in mathematics in 1999 from Saint Mary s College in Notre Dame, IN, and PhD in 2003 from the University of Akron in polymer science under professor Roderic Quirk. Her doctoral research focused on the anionic synthesis and characterization of end functional polymers. She then joined Eastman Chemical Company in Kingsport, TN, where she worked on various process improvement projects and was a project leader for work on the weatherability of copolyesters. She moved to the Center for Nanophase Materials Science in July 2007, where she is a member of the Maaomolecular Nanomaterials Group. She is the recipient of the 2002 Eastman Chemical Company Fellowship, as well as a finalist in the 2002 Id Student Award in Applied Polymer Science. 

In many cases functionality does not affect the hydrodynamic volume of the whole polymer chain significantly and SEC can separate them in terms of molecular weight. In order to separate the polymers in terms of functionality, however, IC has to be used. Pasch and Hiller separated a technical oligo(ethylene oxide) by isocratic RPLC with respect to degree of polymerization and functional end groups, and analyzed the chemical structure by on-line H-NMR detection [ 170]. The experiments was conducted under conditions that are common for HPLC... 

The synthesis of functional polymers is currently seeing a revival. Within the last decade, numerous new polymerizations and functionalization routes for the synthesis of polymers have been described. This is an extremely positive development, considering the ever increasing demand of novel and complex polymeric materials in advanced applications. 

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