Structure-reactivity studies on the polymerization and crosslinking behavior of tri(propylene glycol) diacrylate in aqueous solutions

Radiation induced polymerization of tri(propylene glycol) diacrylate (TRPGDA) has been investigated by steady state and pulse radiolysis (PR) techniques. Reactions of TRPGDA with primary species of water radiolysis such as OH radical, eaq-, H atom and oxidizing species like N3 are reported. The rate constant values of 2.9 ± 0.19 × 109 dm3 mol−1 s−1 and 1.3 × 109 dm3 mol−1 s−1 were obtained for the reaction of TRPGDA with eaq- and OH radical, respectively. The spectrum of hydrated electron was found to be pH dependent whereas the spectrum of transient species formed with OH radicals was found to be unaffected with pH variation. The radical anion formed, preferentially undergoes propagation. The OH adduct was found to be an α-carboxyalkyl radical with an absorption maximum at 300 nm. Steady state investigation reveals a significant dependence of the polymerization behavior on the nature of radiolytic species present and on the ambient environment. A very efficient function of TRPGDA as a crosslinker in poly(vinyl alcohol) matrix was demonstrated by the reduction in Dgel value from 1.1 kGy to 0.2 kGy for crosslinking in presence of 1% TRPGDA.