TECHNOLOGY FOCUS - POLYMERS - Preferred Component: An adhesive is applied to the surface of the grooves or included as a component of the sealing material for adhering the gaskets in the grooves. The gasket (10) includes upstanding bead(s) extending along its surface for improving sealing relationship between fuel cell plates (22, 24). The polydiorganosiloxane is a vinyl terminated polydimethylsiloxane having a viscosity of at least 55 Pa.s or a blend of lower and higher viscosity vinyl containing polydimethylsiloxanes so that the viscosity of the blend is at least 55 Pa.s. It can be vinyl terminated methyltrifluoropropylsiloxane dimethylsiloxane copolymer in which the methyltrifluoropropyl is 10-100 mol.%, or a vinyl terminated diphenylsiloxane dimethylsiloxane copolymer in which the diphenylsiloxane is 2-50 mol.%. The platinum type catalyst is encapsulated in a thermoplastic organic polymer. It can be replaced with organic peroxide present in 0.5-5 parts/100 parts of the sealing material. The sealing material is cured by heating to 100-200degreesC.Preferred Composition: The gasket comprises a curable sealing material containing 100 pbw polydiorganosiloxane having two or more silicon atom bonded alkenyl groups in each molecule, 5-50 pbw reinforcing filler, 1-20 pbw oxide or hydroxide of an alkaline earth metal with an atomic weight of at least40, an organohydrogensiloxane containing at least 3 silicon atom bonded hydrogen atoms in each molecule, platinum type metal catalyst in an amount providing 0.1-500 pbw platinum type metal per 1 million pbw polydiorganosiloxane. The hydrogen atoms are present in an amount providing a molar ratio of silicon atom bonded hydrogen atoms to silicon atoms bonded alkenyl groups in polydiorganosiloxane in 0.4:1-5:1.The sealing material further comprises 0.1-5 pbw organic peroxide in combination with the platinum type catalyst or in place of the catalyst, 0.01-5 pbw inhibitor, and 0.01-100 pbw non-reinforcing extending filler. EXAMPLE - A silicone material composition comprising (pbw) dimethylvinylsiloxy terminated dimethyl trifluoropropylmethyl siloxane copolymer (111), amorphous fumed silica (39), hexamethyldisilazane (6.6), 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane platinum complex (5), decamethylcyclopentasiloxane (2.9), and hydroxy terminated dimethyl methylvinyl polysiloxane copolymer (1) was mixed with silicone material composition comprising (pbw) dimethylvinylsiloxy terminated dimethyl trifluoropropylmethyl siloxane copolymer (110), amorphous fumed silica (38), hexamethyldisilazane (6.4), dimethyl hydrogensiloxy modified silica (3.8), hydroxy terminated dimethyl methylvinyl polysiloxane copolymer (1), and 1-ethynyl-1-cyclohexanol (0.2); and press molded at 171degreesC for 5 minutes and post cured for 4 hours ate 200degreesC. The composition exhibited 44 Shore A durometer, 693 psi tensile at break, 293% elongation at break, 101 ppi tear, and 193 psi modulus at 100% elongation.