Copolymerization of vinyl chloride with bis(beta‐chloroethyl) vinylphosphonate

Abstract

Bis(beta‐chloroethyl) vinylphosphonate and vinyl chloride were copolymerized free‐radically in water suspension and in toluene solution at 55°C. From compositional analysis of the low‐conversion copolymers, the reactivity ratios of bis(beta‐chloroethyl) vinylphosphonate (r1) and vinyl chloride (r2) were found to be 0.37 ± 0.1 and 0.26 ± 0.05, respectively, indicating that the two monomers have a marked tendency to alternate. From the Q and e values of vinyl chloride, the corresponding Q.e values for the vinylphosphonate are calculated to be 0.23 and 1.73, respectively. Interestingly, the rate of copolymerization is greater than that of homopolymerization, and is also greater when water is present. These copolymerization characteristics are deemed favorable in industrial productions. The copolymers have lower viscosities and glass temperatures than poly (vinyl chloride). From patent literature, the copolymers also show useful flame retardant properties.

Flame Retardants

“…Organophosphorus Monomers. Many vinyl monomers containing phosphorus have been described in the literature (110,111), but few have gone beyond the laboratory. Methacryloxyethyl acid phosphates are commercially available but appear to be used in coatings as adhesion improvers, not as flame retardants.…”