Experimental and theoretical investigations of free radical photopolymerization: Inhibition and termination reactions

POLYMER

卷:160

Article

Christmann, Julien¹  Ley, Christian¹  Allonas, Xavier¹  Ibrahim, Ahmad¹  Croutxe-Barghorn, Celine¹ 

[1] Lab Macromol Photochem & Engn, 3b Rue Alfred Werner, F-6809 Mulhouse, France

关键词: Radical photopolymerization;    Kinetic modeling;    Type-I photoinitiator;    Oxygen inhibition;    Termination reactions;    Steady-state assumption;   

DOI  :  10.1016/j.polymer.2018.11.057

来源: Elsevier

【 摘 要 】

In this work, the inhibition and termination reactions occurring throughout a free radical photopolymerization initiated by a type-I photoinitiator are studied by kinetic modeling. The role of the macroradicals as the main oxygen trapping agents during the inhibition time is identified, and the absence of primary radical consumption by oxygen can be related to a high initiation efficiency at early times. The ratio of the termination reactions reveals that bimolecular termination remains the principal pathway for the cessation of macromolecule growth, even at high polymer conversion. Moreover, the evolution of the termination ratio during the polymerization can be correlated to both the diffusional control of the polymerization reactions as the polymer network grows and the photoinitiator consumption. Finally, the effect of the incident light intensity and the initial photoinitiator concentration on the termination reactions is assessed, and the validity of the steady-state assumption applied to the macroradical concentration discussed.

【 授权许可】

Free