ABSTRACT
Partially hydrolyzed poly(lignin-g-(1-amidoethylene)) lowers yield point, lowers gel strength, lowers API filtrate volume, and, after the mud has been hot-rolled at 250°F for 16 hours, functions more effectively as a thinner and agent to control filtration loss than does an equal concentration of chrome lignosulfonate in a water-base mud containing 28 ppb Wyoming bentonite. Poly(lignin-g-(1-amidoethylene)) is formed along with poly(1-amidoethylene) in a graft copolymerization reaction of 2-propenamide on Kraft pine lignin contained in 1, 4-dioxacyclohexane. Formation of graft copolymer was proved by attachment of a derivitized, 1-amidoethylene sidechain to lignin and demonstration by U.V. spectroscopy that sidechain and backbone migrate together in a size exclusion column.
The dried, two-part reaction product is treated with aqueous base to form anionic polymers which produce the changes in mud rheology noted above. Both components of the reaction product are active in controlling mud properties.
