Emulsion polymerization of ethyl acrylate has been carried out in the presence of two kinds of silica, either functionalized by treatment with methacryloylpropyltrimethoxysilane, or not. Both polymerization and grafting kinetics were followed. A part of the polymer is covalently grafted onto silica only if the latter is functionalized and the grafting process takes place at the beginning of the process. The grafted polymer is tightly linked to the silica surface as a succession of small-sized loops. High-molecular-weight non-grafted polymer is also produced with compressed conformation, its radius of gyration being much larger than the thickness of the polymer layer encapsulating the silica.