NOVELTY - A proton conductive membrane (13) for a fuel cell or a reactor based on fuel cell technology, comprises a thin sheet of polyacrylamide modified by sulfonic acid, that allows migration of protons from one side of the membrane to the other. The sulfonic acid is para-chlorobenzene sulfonic acid.    USE - For a fuel cell or a reactor based on fuel cell technology such as direct methanol fuel cell (DMFC).    ADVANTAGE - The membrane is not affected by reactants that common in direct methanol fuel cell (DMFC) cells and is not permeable to ions other than protons/hydroxonium ions and it does not conduct electrons. The method results in improved sealing as well as elimination of the risk of damages to the thin membrane in connection with the mounting of membrane, and the catalyst can better creep into the wall of the membrane as compared to the case in connection with pressing. The polyacrylamide modified by p-chlorobenzene sulfonic acid solves the problems that higher contents of methanol can attack membranes of other polymeric materials and that methanol tends to migrate through the membrane and thereby impair the efficiency of the cell. If there is liquid on the other side of the membrane of the modified polyacrylamide can be almost eliminated, thus the membrane is well suited for cells that have liquid in both cell halves.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for manufacturing proton conductive membrane from a by sulfonic acid modified polymer, for a fuel cell or a reactor based on fuel cell technology, involving mixing acrylamide with para-chlorobenzene sulfonic acid in water; adding a cross-linking agent when the solution has reached room temperature, which cross-linking agent gives the final polymer a stable spatial configuration; initiating the actual polymerization by the addition of a setting agent, and molding the obtained mixture.    DESCRIPTION OF DRAWING(S) - The figure shows a simplified cross-sectional view of the cell that has been prepared for the molding of proton conductive membrane between electrodes.    Anode (11)    cathode (12)    Proton conductive membrane (13)    Porous catalyst carrier (14)    Surface structure (16)    Spacing frame. (17)