VEOVAVinyl Ester of Versatic Acid
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The new dispersion known as DXV.4229 contains waterglass, also known as sodium silicate, to increase the pH and a stabilized hydrophobic polymer based on VeoVa vinyl ester.
Yingli, "Synthesis of a novel polymerizable surfactant and its application in the emulsion polymerization of vinyl acetate, butyl acrylate, Veova 10, and hexafluorobutyl methacrylate," Journal of Applied Polymer Science, vol.
VeoVa has the same reactive group as vinyl acetate; its reactivity is close to that of vinyl acetate in free radical polymerization.
At room temperature, the water solubility of VA is 2.58% and VeoVa is 0.0001% (-7).
The rate of hydrolysis was reduced with increasing proportion of branched hydrophobic vinyl comonomers (VeoVa).
The authors further observed that an ethylene comonomer on a vinyl acetate backbone exerted the same level of hydrolytic resistance on a weight basis as VeoVa. The authors concluded that it is possible that ethylene exerts some protection of vinyl acetate units by increasing the steric effects of the polymer backbone through more compact folding, thus leading to more effective shielding of the hydrolyzable units.
It should be noted that the chemical structure of VeoVa represents only the main component as the commercially available product is usually a mixture of several isomers.
To investigate the extent of these deviations, copolymer emulsions of VA with butyl acrylate (BA), 2-ethyl hexyl acrylate (2-EHA), and VeoVa were prepared under emulsion polymerization conditions.
Table 1--Reactivity of Vinyl Acetate with Other Monomers Monomer Monomer r1 = [k.sub.11]/ r2 = [k.sub.21]/[k.sub.22] 1 (M1) 2 (M2) [k.sub.12] VA BA 0.06 6.00 VA 2-EHA 0.10 9.20 VA E 1.49 0.77 VA VeoVa 0.99 0.93 K11: Polymer-M1* + M1 [right arrow] Polymer-M1-M1* K12: + M2 [right arrow]-Polymer-M1-M2* K21: Polymer-M2* + M1 [right arrow] Polymer-M2-M1* K22: + M2 [right arrow] Polymer -M2-M2* COMPARISON OF COPOLYMER MORPHOLOGY