Common commercially available monomers

The first approach has been important commercially. The monomer most commonly used is a-methylstyrene (see Section 16.11), whose polymer has a Tg of about 120°C. The heat distortion temperature of the resultant-ABS type polymer will depend on the level of replacement of styrene by the a-methyl-styrene. (It may be noted in passing that a-methylstyrene-acrylonitrile binary copolymers have been available as alternatives to styrene-acrylonitrile materials but have not achieved commercial significance.)... 

The most general and frequently used method to synthesize long chains of block copolypeptides for vesicle assembly is successive ring opening polymerizations of a-amino acid-Ai-carboxyanhydride (NCA) monomers [18, 20, 21, 39-51]. NCA monomers are readily prepared from commercially available amino acids, most commonly through direct phosgenation [52]. 

The above synthetic method for well-defined aromatic polyamides, however, needs a peculiar base, N-oclyl-N-triethylsilylaniline, along with CsF and 18-crown-6, and the monomer has a phenyl ester moiety as an electrophilic site, which is not that common compared with a methyl ester or an ethyl ester. Furthermore, it is necessary to separate the obtained polyamide from by-products, such as AT-octylaniline and phenol, by HPLC. For convenient synthesis, the polycondensation of the corresponding methyl ester monomer 22b with a commercially available base has been developed [301]. The methyl ester 22b polymerized with LiHMDS in the presence of an initiator in THF at -10 °C (Scheme 86). The highly pure polyamide with a defined molecu-... 

Like amino acids, PNA monomers have a carboxyl group and an amino group. Thus, they can be assembled into peptide chains like ordinary amino acids. Monomers with f-Boc or Fmoc protection on the amine are commercially available from, e.g.. Applied Biosystems, and the different considerations for PNA synthesis are well described (29). Steps and reagents not commonly used in peptide synthesis but important for PNA synthesis are as follows ... 

The complete hydrogenation of block copolymers of styrene with diene monomers has been reported. Poly(styrene- /oc -diene) based block copolymers in which the polydiene block has been hydrogenated have been commercially available since the 1960s. The most common polymeric structures of this type are based on poly(styrene-bl-butadiene-bl-styrene) and poly(styrene-bl-... 

The monomers that have been explored most extensively are propylene carbonate methacrylate (PCMA) and propylene carbonate acrylate (PCA). These monomers are readily copolymerized with other commonly used unsaturated monomers to yield polymers with cyclic carbonate functionality. There are a few patents discussing the formation of coatings by the amine cross linking of these cyclocarbonate functional polymers. However, they do not appear commercially available. Thus, their use in the preparation of cyclic carbonate functional polymers has been limited. 

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