The Collaborative International Dictionary of English v.0.48:

Polymerize \Pol"y*mer*ize\, v. t. (Chem.)
   To cause polymerization of; to produce polymers from; to
   increase the molecular weight of, without changing the atomic
   proportions; thus, certain acids polymerize aldehyde.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Polymerize \Pol"y*mer*ize\, v. i. (Chem.)
   To change into another substance having the same atomic
   proportions, but a higher molecular weight; to undergo
   polymerization; thus, aldehyde polymerizes in forming
   paraldehyde.
   [1913 Webster]

WordNet (r) 3.0 (2006):

polymerize
    v 1: cause (a compound) to polymerize [syn: polymerize,
         polymerise]
    2: undergo polymerization [syn: polymerize, polymerise]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "polymerize":
   acetify, acidify, acidulate, alkalify, alkalize, borate, carbonate,
   catalyze, chemical, chlorinate, electrolyze, ferment,
   homopolymerize, hydrate, hydrogenate, hydroxylate, isomerize,
   nitrate, oxidize, pepsinate, peroxidize, phosphatize, reduce,
   sulfate, sulfatize, sulfonate, work