Preprint
Article
Modeling the Dual-function Effects of Hybrid-photopolymerization in Iodonium/Amine and Two Monomers System
This version is not peer-reviewed.
Submitted:
10 July 2021
Posted:
14 July 2021
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Abstract
The synergetic features of a three-component photoinitiating systems(A/B/C) based on the measured data and proposed mechanism of Liu et al are analyzed. The co-initiators/additivesB and C have dual-functions of : (i) regeneration of photoinitiator A, and (ii) generation of extra radicals for enhanced conversion efficacy (CE), the synergic effects lead to higher CE for both free radical polymerization(FRP) and cationic polymerization (CP). The CE of FRP has 3 terms due to the direct (tyep-I) coupling and two radicals. Therefore, it is always higher than that of CP having only one radical. The CE of CP has a transient state proportional to the effective absorption constnat (b), the light intensity (I) and initiator concentration (A0), but a steady state given independent to the light intensity (I). For the CE of FRP, the contribution from radical R could have two cases: (i)linear dependence on T'=bIA0, or (ii) nonlinear square root dependence T0.5. The nonlinear feature is due to the bimolecular termination term of k'R2.The key factors influencing the conversion efficacy are explored by analytic formulas. The synergetic effects lead to higher conversion of FRP and CP are consistent with the measured work. However, there are other theoretically predicted new features (findings) which are either not identified or explored experimentally including: (i) co-initiator [C] always enhances both FRP and CP conversions, whereas co-initiator [B] leads to more efficient FRP, but it also reduces CP. The specific systems analyzed are: benzophenonederivatives(A) ethyl 4-(dimethylamino)benzoate (B), and (4-tert-butylphenyl)iodonium hexafluorophosphate (C) under a UV (365 nm) LED irradiation; and two monomers of trimethylolpropane triacrylate (TMPTA, for FRP) and (3,4- epoxycyclohexane)methyl 3,4-epoxycyclohexylcarboxylate (EPOX, for CP).
Keywords:
polymerization kinetics
; photoinitiator
; monomer conversion profile
; synergetic effects.
Copyright: This open access article is published under a Creative Commons CC BY 4.0 license, which permit the free download, distribution, and reuse, provided that the author and preprint are cited in any reuse.
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