Fillers as Heaters for Photothermal Polymerization upon NIR Light.

Area of Science:

• Materials Science
• Polymer Chemistry
• Photochemistry

Background:

• Photo-induced thermal polymerization utilizes near-infrared (NIR) light to initiate polymerization.
• This process requires a heat generator (heater) and a thermal initiator for free-radical polymerization of (meth)acrylates.
• Organic NIR absorbers have been used, but fillers offer alternative heating capabilities.

Purpose of the Study:

• To investigate various fillers (graphene oxide, graphene nanoplatelets, multi-walled carbon nanotubes, silicon carbide) as NIR-absorbing heaters.
• To compare the efficiency of these fillers against organic NIR absorbers in photothermal polymerization.
• To explore the potential of filler-based photothermal polymerization for creating composite materials.

Main Methods:

• Examined fillers (graphene oxide, graphene nanoplatelets, multi-walled carbon nanotubes, silicon carbide) as NIR absorbers/heaters.
• Utilized an alkoxyamine (BlocBuilder-MA) as a thermal initiator, activated by heat generated from NIR light absorption.
• Investigated polymerization using three NIR wavelengths: 785 nm, 940 nm, and 1064 nm.

Main Results:

• Fillers were evaluated for their ability to generate heat upon NIR irradiation.
• The heat generated by fillers initiated the dissociation of the alkoxyamine thermal initiator.
• Successful photopolymerization of (meth)acrylates was achieved, demonstrating the feasibility of filler-based photothermal initiation.

Conclusions:

• Fillers can serve as efficient heaters for NIR-induced photothermal polymerization.
• This approach enables the polymerization of thick samples due to NIR light's deeper penetration.
• Filler incorporation allows for the creation of novel composite materials via photothermal polymerization.