Poly vinylphosphonic acid cements

Ellis and Wilson studied cements formed from concentrated solutions of poly(vinylphosphonic acid) (PVPA) and oxides and silicate glasses, which they termed metal oxide and glass polyphosphonate cements (Wilson  

PVPA was prepared by the free-radical homopolymerization of vinyl-phosphonyl dichloride using azobisisobutyronitrile as initiator in a chlorinated solvent. The poly(vinylphosphonyl chloride) formed was then hydrolysed to PVPA (Ellis, 1989). No values are available for the apparent pA s of PVPA, but unpolymerized dibasic phosphonic acids have and values similar to those of orthophosphoric acid, i.e. 2 and 8 (Van Wazer, 1958). They are thus stronger acids than acrylic acid, which as a pK of 4-25, and it is to be expected that PVPA will be a stronger and more reactive acid than poly(acrylic acid). 

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Ellis, J. Wilson, A. D. (1992). The formation and properties of metal oxide poly(vinylphosphonic acid) cements. Dental Materials, 8, 79-84. 

Wilson, A. D. Ellis, J. (1989). Poly-vinylphosphonic acid and metal oxide or cermet or glass-ionomer cements. British Patent Application 2, 219, 289A. 

Vinylphosphonic acid is produced in Germany and used, initially by Hoechst, later by others to manufacture a hydrophilic poly(vinylphosphonic acid) prepared by free-radical polymerization in a solvent (70,71). Poly(vinylphosphonic acid) is mainly used for the treatment of aluminum photolithography plates before application of the photosensitive layer (72,73). The coating improves the developing and printing characteristics of the plate. Dental cement applications of cross-linked poly(vinylphosphonic acid) have also been studied (74). Vinylphosphonic acid copolymers with vinylsulfonic acid have been patented as scale inhibitors for water treatment (75). 

This chapter is devoted to a miscellaneous group of aqueous acid-base cements that do not fit into other categories. There are numerous cements in this group. Although many are of little practical interest, some are of theoretical interest, while others have considerable potential as sustained-release devices and biomedical materials. Deserving of special mention as biomedical materials of the future are the recently invented polyelectrolyte cements based on poly(vinylphosphonic adds), which are related both to the orthophosphoric acid and poly(alkenoic add) cements. 

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