Yes, MGY friend is correct about the lifebelts having cork in them. However, how would this explain all the cork that was found after Titanic foundered? Somehow the cork would have had to escape all the linen that it was sewn into to create the lifebelts to account for this phenonemon. Otherwise, it would have been hordes of lifebelts littering the wreck site instead of the granualted cork.

Granulated cork was used in Titanic for insulation in the cold storage rooms, the dampening of noise for the 1st Class cabins, to dampen generator noise in the wireless room, and who knows where else. However, since there was really nothing facinating about cork, no known pictures of it on Titanic are known of, and none of it was bothered to be recovered from the scene of the wreck (especially when compared to ornate 1st Class carvings).