Kinetic hydrate inhibitors (KHIs) are used in the oil industry to prevent plugging of pipelines by gas hydrates. Cationic molecules with small alkyl groups, such as tetraalkylammonium and alkylimidazolinium salts are known to be synergists for KHI polymers such as N-vinyl lactam polymers. Instead of using separate synergist and polymer molecules, we have investigated the effect on KHI performance of placing the synergist active groups into N-vinyl lactam copolymers. Thus, 3-alkyl-1-vinylimidazolium bromides and tributylammoniumethylacrylate bromide (TBAEABr) monomers and homopolymers and copolymers with N-vinyl lactams were prepared. These were tested for their performance as KHIs with a Structure II-forming gas mixture as well as their ability to prevent tetrahydrofuran hydrate crystal growth inhibition. We conclude that incorporation of the synergist functional groups into N-vinyl lactam polymers does not give a greater benefit as a KHI than using a physical mixture of the synergist molecule and PVCap polymer. However, a cationic TBAEABr homopolymer showed good kinetic inhibition performance when used alone on both THE and SII gas hydrates. This is the first cationic homopolymer KHI with good performance to be reported. Poly(tributylammonium ethylacrylate bromide) (PTBAEABr) was also a better KHI synergist with PVCap than using tetrabutylammonium bromide. (C) 2013 Elsevier Ltd. All rights reserved.