Sulfur polyacrylic acid

S8 untreated sulfur, PPASg plasma polyacetylene-treated sulfur, PFHSg plasma polyperfluorohexane-treated sulfur, PAASg plasma polyacrylic-acid-treated sulfur n.a. not available... 

L of cultivating liquid with pH 8.2 was mixed with 16 kg oxalic acid acidified with 1 N sulfuric acid to pH 2.9 and was filtered through about 160 kg fossil flour and washed with 500 L water. The filtrate (about 5400 L) was alkalified to pH 7.8-8 with 10% sodium hydroxide and was filtered through fossil flour filter. Then it was passed through two column with polyacrylic acid cation exchange resin in sodium form (US Patent No. 2,915,432). 

Concentrated electrolytes Sodium sulfate-sulfuric acid-water Hydrogen chloride-polyacrylic acid-water... 

Amine Cross-Linking. Two commercially important, high performance elastomers which are not normally sulfur-cured are the fluoroelastomers (FKM) and the polyacrylates (ACM). Polyacrylates typically contain a small percent of a reactive monomer designed to react with amine curatives such as hexamethylene-diamine carbamate (Diak 1). Because the type and level of reactive monomer varies with ACM type, it is important to match the curative type to the particular ACM ia questioa. Sulfur and sulfur-beating materials can be used as cure retarders they also serve as age resistors (22). Fluoroelastomer cure systems typically utilize amines as the primary cross-linking agent and metal oxides as acid acceptors. 

The polyacrylates were synthesized with deuterium labels on the methine position on the backbone. The monomeric acrylates were made by the exchange of the methine proton on acrylonitrile with D2O, hydroquinone and CaO, as previously reported for iso-propyl acrylate.(i) The nitrile group was converted to the appropriate ester with the appropriate alcohol and sulfuric acid. Since our first report, a more facile synthesis of these monomers has been reported.(T) The polymerizations were carried out in toluene using azobis-/so-butyronitrile (AIBN) as an initiator. The reaction scheme is given below. 

To purify the product, the polyacrylic hydrazide is dissolved in 50 ml of water and again precipitated with methanol. This procedure is repeated several times. The product is finally dried in a vacuum desiccator over sulfuric acid at room temperature. The product is stored in the cold in a vacuum desiccator with the exclusion of light. The stability of this polymer, as a non-cross-linked raw material, is poor. In general, this preparation must be carried out quite rapidly. 

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