The goal of this work is to make an injectable physically and chemically cross-linking NIPAAmbased copolymer system for endovascular embolization. A copolymer with N-isopropylacrylamide (NIPAAm) and hydroxyethyl methacrylate (HEMA) was synthesized and converted to poly (NIPAAm-co-HEMA-acrylate) functionalized with olefins. When poly(NIPAAm-co-HEMAacrylate) was mixed with pentaerythritol tetrakis 3-mercaptopropionate (QT) stoichiometrically in 0.1 N PBS solution of pH 7.4, it formed a temperature-sensitive hydrogel with low swelling through the Michael-Type Addition reaction and showed improved elastic properties at low frequency compared to physical gelation. This material could be useful for applications requiring water-soluble injection but lower swelling and lower creep properties than available with other soluble in situgelling materials.