<prompt> The liquid component of hybrid ionomer cements usually contains a water solution of:HEMAPolyacrylic acidPolyacrylic acid modified with methacrylateAll of the above  <response>: The liquid component of hybrid ionomer cements usually contains a water solution of polyacrylic acid, HEMA, and polyacrylic acid modified with methacrylate. The powder component contains fluoroaluminosilicate glass particles of a conventional GIC plus initiators, such as camphorquinone, for light curing andor chemical curing. The acid-base reaction begins upon mixing and continues after polymerization at a much slower rate than for conventional GICs, because less water is present and the reaction is much slower in the solid phase than in the liquid phase.Ref: Phillips Science of Dental Materials ed 12 pg 326 