Synthesis and properties of block poly(styrene amides) and poly(styrene esters)

Three series of block copolymers, namely, polystyrenecaproamide (I), polystyrenehexamethyleneadipamide (II), and poly(styreneethylene terephthalate) (III), were prepared, and the properties of the copolymers in relation to the block sequence lengths and the compositions were studied. Styrene was polymerized in the presence of aluminum chloride and thionyl chloride to give ω,ω′-dichloropolystyrenes of various degrees of polymerization from 12.0 to 51.0, which were either ammonolyzed to ω,ω′-diaminopolystyrene or hydrolyzed to ω,ω′-dihydroxypolystyrene. ω,ω′-Diaminopolystyre was treated with adipic acid to give the corresponding salts, namely, ω,ω′-diammoniumpolystyrene adipate, which was melt-polymerized either with ε-amino-n-caproic acid to give polystyrenecaproamide (I) or with hexamethylenediammonium adipate to give polystyrenehexamethyleneadipamide (II). ω,ω′-Dihydroxypolystyrene was melt-polymerized with dimethyl terephthalate and ethylene glycol to give poly(styreneethylene terephthalate) (III). All the block copolymers were of high enough molecular weight to be cast or spun into films or filaments. Upon polymerization, the increase of the block sequence of PSt units increased the amide content but decreased the ester content of the resulting copolymers. Also, an increase in n decreased the inherent viscosities of the copolymers at a constant monomer feed f_c counted by the polymer equivalent of PSt but increased the inherent viscosities at a constant monomer feed r_c counted by the monomer equivalent of PSt. The melting points of the copolymers decreased with increasing n values. Also, an increase in n decreased the densities of I and III but increased the density of II at a constant amide or ester composition F_c counted by polymer units but increased the densities of I, II, and III at a constant amide or ester composition R_c counted by the monomer unit.