The invention relates to a curable 
sealant composition broadly comprising a resealable, swellable, reactive 
sealant and free 
radical initiator; said resealable, swellable reactive 
sealant comprises monofunctional 
monomer(s), multifunctional 
monomer(s), 
reactive polymer such as unsaturated styrenic block 
copolymer, swellable additive, and optional components. The monofunctional 
monomer is a 
vinyl ester derivative of versatic acid with C9-C12 carbon atoms, or monoacrylate, monomethacrylate, monoacrylamide, or monomethacrylamide. The multifunctional monomer are di-, tri-, 
tetra-, and / or penta-functional monomers with vinyl, 
acrylate, 
methacrylate, 
acrylamide, or 
methacrylamide functionality, such as tricyclodecane dimethanol diacrylate, 
trimethylolpropane trimethacrylate, 1,3-butylene 
glycol dimethacrylate or a mixture thereof. The reactive unsaturated 
polymer is a styrenic block 
copolymer such as SBS, SIS, S-I / B-S, I-SEBS-I, and mixtures of two or more of these. The swellable additive is selected from saturated block copolymers such as SEBS, SEPS, SEEPS, and I-SEBS-I, or a mixture of these. Free radical initiators are preferably peroxides, although others are acceptable.