Alkylate Arylate-Siloxane Copolymers

Alkylate Arylate-Siloxane Copolymers.—Data published on the thermal stability of poly(phenolphthalein terephthalate/dimethylsiloxane) block copolymers, in 

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In addition to providing fully alkyl/aryl-substituted polyphosphazenes, the versatility of the process in Figure 2 has allowed the preparation of various functionalized polymers and copolymers. Thus the monomer (10) can be derivatized via deprotonation—substitution, when aP-methyl (or P—CH2—) group is present, to provide new phosphoranimines some of which, in turn, serve as precursors to new polymers (64). In the same vein, polymers containing a P—CH3 group, for example, poly(methylphenylphosphazene), can also be derivatized by deprotonation—substitution reactions without chain scission. This has produced a number of functionalized polymers (64,71—73), including water-soluble carboxylate salts (11), as well as graft copolymers with styrene (74) and with dimethyl siloxane (12) (75). 

The major categories of homopolymers and copolymers to be discussed are31 (i) linear siloxane polymers [-SiRR O-] (with various alkyl and aryl R,R side groups),... 

A wide range of dithioester RAFT agents has been reported. Common examples of mono-RAFT agents and their application are provided in Tables 11 (Z = aryl) and 13 (Z = alkyl or aralkyl). RAFT agents can contain various unprotected functionality on the R fragment of dithiobenzoate including hydroxy, carboxylic acid/carboxylate, sulfonic acid/sulfonate, olefin, and siloxane. Examples of bis- and multi-dithioester RAFT agents (Z=aryl) that may be used for triblock or star synthesis are shown in Tables 12 and 22, respectively. Bis-dithioesters can be used to synthesize triblock copolymers in a two-step process. 

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