Thiol-ene polymer microbeads prepared under high-shear and their successful utility as a heterogeneous photocatalyst via C60-capping

• A series of thiol-ene PMBs were prepared via high-shear suspension photopolymerization.
• Thiol-ene PMBs possessed narrow size distributions and high monomer conversion.
• Composition affects PMB size, smaller particles result from increased functionality.
• Thiol-ene PMB utility as scaffolding material using follow-on, thiol-ene reactions.
• C60-PMB heterogeneous photocatalyst efficiently generates 1O2 and is recyclable.

A series of thiol-ene (1.1:1 equiv) polymer microbeads (PMBs) were prepared via a high-shear suspension photopolymerization method to explore the physical properties of the networks as a function of composition. 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H, 3H, 5H)-trione (TTT) and pentaerythritol tetrakis (3-mercaptopropionate) (PETMP) PMBs were selected for the synthesis of a heterogeneous photocatalyst. Particle size was characterized using DLS and OM, and thermal stability and Tg were assessed using TGA and DSC. PMBs produced from higher functionality monomers produce smaller particles, and Tg increased with monomer rigidity. TTT-PETMP PMBs were derivatized with C60 to demonstrate the accessibility and reactivity of the residual thiols, successful inclusion of C60 as the reactive ene moiety, and overall PMB utility as a scaffold material. Upon capping with C60, the Tg of the composite particles increased significantly. Most importantly, the C60-capped PMBs produced singlet oxygen in direct and indirect chemical assays, and the efficiency did not decrease after recycling.

Preparation of C60-capped thiol-ene PMBs.Figure optionsDownload high-quality image (198 K)Download as PowerPoint slide