Suspending agents sodium poly

Typical suspending agents for the vinyl acetate polymerization are poly(vinyl alcohol) [particularly a grade represented as approximately 88% hydrolyzed poly(vinyl acetate)], gum arabic, hydroxyethyl cellulose, methyl cellulose, starches, sodium polyacrylate or sodium polymethacrylate, gelatin, and an equimolar copolymer of styrene and maleic anhydride neutralized with either sodium hydroxide or aqueous ammonia. Water-insoluble dispersing agents or... 

Sodium thiosulfate interfered with the polymerization in the aqueous phase. This manifested itself in a decrease in the overall rate of polymerization (cf. Table XVII). In this woric, substantial additions of sodiiun chloride were made to the aqueous phase to reduce further the unwanted emulsion polymerization. The suspending agent used in these experiments was a partially saponified poly(vinyl acetate) whose trade designation is Rhodoviol HS 100. This poly-(vinyl alcohol) was normally added to the reaction system as a 6% aqueous... 

In a flask equipped with an explosion-proof mechanical stirrer with adjustable speed, an additional funnel, a thermometer, and a reflux condenser, 80 gm of anhydrous sodium sulfate is dissolved in 400 gm of water. Then 8 gm of a lO o aqueous solution of sodium poly(acrylate) is added as the suspending agent. After the addition of 100 gm (1.16 moles) of inhibited methacrylic acid containing 0.2 gm (0.0008 mole) of benzoyl peroxide, the reaction system is stirred continuously but not too rapidly and heated at 80 C with a water bath for approximately 2.5 hr. A small quantity of the 1097o aqueous solution of sodium poly(acrylate) is maintained in the addition funnel throughout the process so that part of this reagent may be added if there are indications of lump formation. 

Besides sodium poly (aery late), other suggested suspending agents are sodium isopropylnaphthalene sulfonate, talc, gelatin, gum tragacant, water-soluble starches, barium sulfate, and other inorganic colloids or powders. 

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