Provided are gel particles each having a three-dimensional crosslinked structure having at least one bond selected from a urethane bond and a urea bond, the gel particles each including: a maleimide group represented by Formula 1 below, a photosensitive composition, an ink composition, a method of producing water dispersion of gel particles, and an image forming method. In Formula 1, R.sub.1 and R.sub.2 each independently represent a hydrogen atom or an alkyl group, R.sub.1 and R.sub.2 may be bonded to each other to form a ring, and * represents a bonding site.

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A downhole sealing device, a well system employing a downhole sealing device, and a method for sealing within a wellbore. The downhole sealing device, in one aspect, includes one or more downhole sealing features, and an elastomeric element comprising a thiourethane/acrylate polymer coupled to the one or more downhole sealing features. In at least one aspect, the elastomeric element is operable to be compressed in a downhole application against a tubular as a seal.

Suggested is an improved process for making urea urethanes according to which in a first step hydroxy compounds are reacted with diisocyanates to form a prepolymer which is subsequently reacted with a diamine. The formation of the urea urethanes is conducted in the presence of new stabilizers derived from urea.

The present invention discloses a one-step polyurethane (PU) depolymerization to recover isocyanates and regenerate both thermoplastic and thermoset PUs. The method uses a halide-containing boron compound to depolymerize PUs directly to isocyanates under mild conditions (e.g., <100 C. in toluene). Also, disclosed herein is depolymerization of both model and commercially available PUs and regeneration of PUs using recovered isocyanates, with molecular weight distributions and thermomechanical properties that are equivalent to virgin PUs with yields of up to 50%.