Metal acetylacetonate as a radical initiator and catalyst for polyurethane in dual-curing reaction at low temperature

Abstract

The goal of our research has been to realize dual-curing reaction which is accompanied with radical reaction and urethane reaction at low temperature using a metal acetylacetonate (Mt(acac)(x)) such as Mn(acac)(3), Mn(acac)(2), Co(acac)(3), Co(acac)(2) and Zn(acac)(2). To understand radical reaction relationship depending on what kind of metals, Mt(acac)(x) as a radical initiator is defined by DSC analysis in n-butyl acrylate and EPR spectroscopy. The role of finding T(Pea)k in DSC and g factor in EPR exhibit Mt(acac)(x) can generate radical effectively. In order to verify effect of Mt(acac)(x) in urethane reaction on HFUMO 4039-0 without acryl group and PL-350, real-time storage modulus (G') was measured by rheometer for curing at 140 degrees C and checked the initiation temperature (T-init) and storage modulus (G'). Finally, to evaluate the catalyst the effect of Mt(acac)(x) as a radical and urethane reaction, rheometer and nanoindenation were constructed with HFUMO 4039-60 with acryl group and PL 350 based on films cured at 140 degrees C, 120 degrees C and 100 degrees C. Considering the initiation temperature (T-init) and storage modulus (G') on rheometer and HIT value on nanoindenation, Mn(acac)(3) is the best catalyst among tested Mt (acac)(x) and surface property also maintained despite 100 degrees C even low curing temperature.