Structural and Mechanical Properties of “Peelable” Organoaqueous Dispersions with Partially Hydrolyzed Poly(vinyl acetate)-Borate Networks: Applications to Cleaning Painted Surfaces

The preparation and structural characterization of a family of viscoelastic dispersions of borate cross-linked, 80% hydrolyzed poly(vinyl acetate) (80PVAc) in aqueousorganic liquids are presented. Correlations between mechanical properties (from rheological measurements) and the degree and nature of cross-linking (from 11 B NMR spectroscopy) are reported, and the results are used to assess their potential as low-impact cleaning agents for the surfacesofpaintings.Becausethedispersionscanbepreparedatroomtemperature by simple procedures from readily available materials and can contain up to 50% (w/w) of an organic liquid, they offer important advantages over previously described cleaning agents that are based on fully hydrolyzed PVAc (i.e., poly(vinyl alcohol). The mechanical properties of the various aqueousorganic dispersions, asdeterminedquantitativelybyrheologicalinvestigationsandqualitativelybytheir ease of removal from a solid surface (i.e., the so-called "peel-off" ability) have been tuned systematically by varying the amount of organic liquid, its structure, and the concentrations of borax and 80PVAc. The 11 B NMRstudiesdemonstratethattheconcentrationofborateionsactivelyparticipatingincross-linkingincreasessignificantlywiththe