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 ]
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 ]