RADIATION POLYMERIZATION OF ACETYLENE DERIVATIVES

Exploratory research on the radiation-induced polymerization of acetylene derivatives to produce polyene polymers with useful properties included synthesis of acetylene derivatives, screening monomers for radiation sensitivity, correlation of chemical structure with sensitivity, attempts to establish optimum polymerization conditions, and characterization of the products. A total of 48 acetylene derivatives were screened for radiation sensitivity during the year. Radiation yields with G values greater than 100 were observed ith propiolic acid, G = 322; 2-butyn-1,4-dipropiolate, G = 103; neopentylene dipropiolate, G = 177; and pentaerythritol tetrapropiolate, G = 113. Other moderately radiation sensitive systems include: phenylpropiolic acid, G = 73; phenylbromoacetylene, G = 94; 2-butyn-1,4-diacetate, G = 96 and bis-1,4(hydroxyethyloxy)-butyne-2, G = 57. (G value = number of monomer molecules that polymerize per 100 ev of radiation). In general, the acetylenic monomers exhibit good radiation sensitivity, but the products obtained appear to be of low molecular weight. Among the functional groups affecting radiation sensitivity, the carboxyl group appeared especially sensitive. Monopropiolates were fairly radiation-sensitive; all polypropiolate esters studied were very radiation sensitive.